CN102323394A - Experimental apparatus and method for researching response characteristic of natural gas hydrate stratum to drilling fluid intrusion - Google Patents

Abstract

The invention relates to an experimental device and an experimental method for studying the response characteristics of natural gas hydrate formations to drilling fluid invasion. Tracking mechanism, back pressure mechanism, detection mechanism, outlet metering mechanism, core transfer mechanism, sampling mechanism and industrial computer; the experimental method is completed on the device, there is a method of gas permeability test of hydrate deposits, and the effect of drilling fluid on hydrate deposition An experimental method for monitoring the dynamic response characteristics of hydrate sediments during the intrusion and intrusion process; a fidelity transfer method for hydrate sediment cores. The present invention provides an early indoor study on the response characteristics of natural gas hydrate formations to drilling fluid invasion, which can grasp the law of the influence of drilling fluid invasion on the physical properties of hydrate formations, and can realize the fidelity transfer of simulated hydrate-containing sediment samples. It provides a basis for formation development drilling safety and accurate logging interpretation.

Description

Experimental device and experimental method for studying the response characteristics of natural gas hydrate formations to drilling fluid invasion

technical field

The invention relates to an experimental device and an experimental method for studying the response characteristics of natural gas hydrate formations to drilling fluid invasion.

Background technique

Natural gas hydrate has the characteristics of high energy density, wide distribution, and large reserves, and is a new type of alternative energy with great potential. But so far, there are still "three dark clouds" in the sky of hydrate exploration and development and application: insufficient quantitative description of reservoirs, unqualified mining technology and high risk of development and application. Since the gas hydrate formation is a porous medium with permeability, drilling fluid will inevitably exchange energy and matter with it during drilling, which will affect the wellbore stability, logging response and reservoir evaluation. In the case of overpressure drilling and drilling fluid temperature higher than the hydrate phase equilibrium temperature here, the displacement and invasion of gas hydrate-bearing formations by water-based drilling fluid and the dissociation of gas hydrates caused by heat conduction under temperature differences are coupled together. The process is a non-isothermal non-steady-state percolation-diffusion process involving phase transitions. Only common numerical simulation methods have shortcomings such as model assumptions and simplifications, which cannot truly and accurately reflect the actual situation. In addition, there are few actual drilling activities in field hydrate formations, and the operation is difficult, costly, and risky. The internal conditions are often invisible, and there are still many uncertainties in inferring the reservoir conditions around the well by using the actual logging method. Therefore, people have also carried out some indoor simulation experiments, designed some experimental devices, and established some experimental methods. The method of experimental simulation is used to study the decomposition rate of methane hydrate. In the experiment, methods such as isovolumic temperature rise decomposition and atmospheric pressure decomposition of porous media systems with different particle sizes are used to study the decomposition characteristics of hydrate; the State Intellectual Property Office published in June 2011 "An experimental device for detecting physical properties of natural gas hydrate in three-dimensional formation and production", application number 201010603251.0, this device can accurately measure the change of physical properties during production, and can be used to comprehensively study the basic physical properties of hydrate reservoirs during the formation and production of various hydrates Variety. However, the shortcomings of the above-mentioned experimental devices and methods are that they can only be used for simulation experiments in the process of hydrate production, and ignore the impact of drilling activities and drilling fluid invasion on hydrate formations in the process of hydrate exploration and production. Therefore, it is of great significance to study the dynamic response characteristics of hydrate formations to drilling fluid invasion to realize safe and efficient exploration and development of hydrates.

In view of the above situation, it is a reasonable choice to carry out indoor simulation experiments in the early stage of drilling in hydrate formations. It is necessary to establish an experimental device and experimental method that can comprehensively simulate indoors to systematically study the impact of hydrate formations on drilling fluid invasion. The dynamic response characteristics of hydrates provide a theoretical basis and experimental guidance for the safe and efficient exploration and development of hydrates in the future.

Contents of the invention

The purpose of this invention is to provide an experimental device that can comprehensively study the response characteristics of natural gas hydrate formations to drilling fluid invasion, and secondly to provide a set of experimental devices based on the provided experimental device for studying the response characteristics of natural gas hydrate formations to drilling fluid invasion. Complete Experimental Methods.

In order to achieve the above object, the present invention adopts the following technical scheme: provide an experimental device for studying the response characteristics of hydrate formation to drilling fluid invasion, including drilling fluid circulation mechanism, high and low temperature constant temperature test box, gas permeability mechanism, water /Gas injection mechanism and industrial computer, also equipped with core transfer mechanism, ring pressure tracking mechanism, back pressure mechanism, detection mechanism, export metering mechanism, sampling mechanism;

The drilling fluid circulation mechanism is composed of a drilling fluid storage tank, a temperature controller, a drilling fluid circulation pump and a wellhead annular cavity of a physical model mechanism. The circulation flow in the wellhead annulus of the physical model mechanism infiltrates into the hydrate deposits in the core holder;

The high and low temperature constant temperature test box is a programmable constant temperature test box controlled by an industrial computer. A physical model mechanism is provided in the test box. A drilling fluid wellhead ring cavity is provided at the left end of the physical model mechanism, and a sampling point is provided on the upper part. The infrared camera is installed on the pulley track in the experiment box, aligned with the axis of the physical model mechanism, and can move left and right; the physical model mechanism is equipped with a core holder, and the left and right sides of the core holder are provided with left end covers and The right end cover, the test core is placed in the core holder, and the measuring points of resistivity, pressure and temperature are set in the axial direction of the core holder; the physical model mechanism passes the high pressure at the upper, lower and end parts The pipeline is connected with the pressure control valve, the pressure gauge, the gas permeability measurement mechanism, the water/gas injection mechanism, and the sampling mechanism; the sensors at the ten station measuring points on the physical model mechanism are respectively connected to the measurement mechanism through signal lines and high-pressure pipelines connected; when transferring the hydrate sediment core formed in the core holder, connect the right end of the core holder with the core transfer mechanism to realize the transfer;

The gas permeability measurement mechanism contains three sets of nitrogen pipelines with different osmotic pressures, respectively testing the permeability of hydrate deposits with high, medium and low permeability; the water/gas injection mechanism includes liquid water injection Mechanism and natural gas injection mechanism, the liquid water injection mechanism consists of an advection pump and a piston container; the natural gas injection mechanism includes a natural gas cylinder, a pressure reducing valve, a gas booster pump and a gas flow meter, and the gas flow meter controls the amount of natural gas entering the physical model mechanism , realizing the synthesis of hydrate deposits with different saturations in the core holder;

The ring pressure tracking mechanism is composed of a ring pressure tracking pump and a pressure sensor, and tracks the pressure difference between the ring pressure chamber and the inner cavity of the core holder in the physical model mechanism;

The back pressure mechanism is composed of a back pressure valve, a back pressure buffer container and a back pressure pump; the detection mechanism includes a pressure measurement mechanism, a resistivity measurement mechanism, a flow detection mechanism, a temperature control and detection mechanism;

The outlet metering mechanism is composed of a gas-liquid separator, a gas mass flowmeter and an electronic balance; the sampling mechanism adopts a manual pump and a piston sampler, and a pre-increased one and a physical The same pressure in the model mechanism, and then realize equal pressure sampling by withdrawing the pump;

The industrial computer runs under Windows 2000 or XP environment, adopts VB programming, and timely collects and processes various values of pressure, temperature, resistivity, gas volume, and liquid volume, and controls the operation of each mechanism.

In the experimental device of the present invention, the core holder is uniformly arranged with 10 station measuring points in its axial direction, and 10 pressure sensors C, 10 temperature sensors and 10 resistivity sensors are installed respectively.

In the experimental device of the present invention, the specification of the rock core holder is φ50mm, the length is 1200mm, the test core is φ50mm, and the length is 500-1200mm, and the length of the test core is less than 1200mm. Natural core, man-made core or sand-packed models. The said false core lengthening means that when the length of the test core cannot fill the entire core holder, the test core in the core holder is lengthened to 1200mm by using the false core to fill up the entire core Holder. The false rock core is a hollow cylindrical fake rock core made of stainless steel.

In the experimental device of the present invention, the core fidelity transfer mechanism is composed of an outer cavity, an inner cavity, a piston, a manual pump, an annular cavity, a temperature controller, a pressure controller, a sealing plate and a joint, and the outer cavity There is an inner cavity in the body, a piston is installed at one end of the inner cavity, a packing plate is installed at the other end, the joint is installed outside the packing plate, the pressure controller is connected with the inner cavity, and the temperature controller is connected with the annular cavity.

In order to achieve the second purpose of the present invention, it provides an experimental method for using the experimental device to study the response characteristics of natural gas hydrate formations to drilling fluid invasion, including an experimental method for testing gas permeability of hydrate deposits, drilling The intrusion of liquid into hydrate deposits and the experimental method for monitoring the dynamic response characteristics of hydrate deposits during the invasion process; the fidelity transfer method of hydrate deposit cores; the experimental method for testing the gas permeability of hydrate formations is divided into Experimental methods for testing the permeability of hydrate sediments with three different permeabilities: low, medium and high. The specific steps are as follows:

(1) The steps of the experimental method for permeability testing of low-permeability hydrate sediments:

a. Water injection: the liquid water in the liquid water storage container is injected into the test rock core in the rock core holder through the piston container A through the advection pump;

b. Gas injection: After the liquid water injection is completed, open the natural gas cylinder, and the CH ₄ gas passes through the pressure reducing valve. When the natural gas pressure is lower than the pressure required for the experiment, turn on the gas booster pump to increase the pressure, and the gas pressure is displayed by the pressure gauge D. Flow through the valve ⑤;

c. Select a low-permeability gas injection pipeline. CH ₄ gas passes through the low-permeability pipeline composed of valve ⑥, valve ⑦, and low flow meter, and enters the core holder to test the core. The pressure in the core to be tested reaches the set pressure 8~12MPa and keep it for 2~3 hours, then stop the gas injection;

d heat preservation: adjust the temperature of the high and low temperature constant temperature test box, so that the test core in the physical model mechanism is allowed to stand at a constant temperature of 4°C for 12 to 20 hours, and low-permeability hydrate deposits are formed in the core holder;

e. Permeability by gas measurement: low-permeability experiment is carried out. At this time, valve ①, valve ⑦, and valve ⑥ are opened, other valves are closed, and nitrogen cylinder A is opened. The nitrogen in the cylinder is adjusted to 4MPa by high-pressure pressure regulating valve B and then enters the physical model Mechanism, the gas infiltration pressure is displayed by the pressure gauge E, and the permeability of the low-permeability hydrate deposit is tested by a low-flow meter;

(2) The steps of the experimental method for the permeability test of hydrate sediments with medium permeability:

Steps a and b are the same as the experimental method for low permeability hydrate deposits;

c. Select the medium permeation gas injection pipeline, the natural gas passes through the medium permeation pipeline composed of valve ⑧, medium flow meter and valve _⑨ , injects CH gas into the test core in the core holder, and the pressure in the core to be tested reaches the set value. Set the pressure at 8-12MPa and keep it for 2-3 hours, then stop the gas injection;

d. Heat preservation: adjust the temperature of the high and low temperature constant temperature test box, so that the test core in the physical model mechanism is allowed to stand at a constant temperature of 4°C for 12 to 20 hours, and a medium-permeable hydrate deposit is formed in the core holder ;

e. Permeability measurement by gas: medium infiltration experiment is carried out. At this time, valve ②, valve ③, valve ⑧, and valve ⑨ are opened, and other valves are closed. It is displayed by the pressure gauge A, and then adjusted to 0.6MPa by the medium pressure regulator valve. The gas pressure is displayed by the pressure gauge B, and then enters the physical model mechanism, and the permeability of the medium permeability hydrate deposit is tested by the medium flow meter;

(3) The steps of the experimental method for permeability testing of high permeability hydrate sediments:

Steps a and b are the same as the experimental method for low permeability hydrate deposits;

、高流量计所构成的高渗透管路，向岩芯夹持器中测试岩芯注入CH₄气体，待测试岩芯中压力达到设定压力8～12MPa并保持2～3小时后停止注气； c. Select a high-permeability gas injection pipeline, and the natural gas passes through the valve ⑩, the valve

, high-permeability pipeline formed by a high flow meter, inject CH ₄ gas into the test core in the core holder, and stop the gas injection after the pressure in the test core reaches the set pressure of 8-12MPa and maintains it for 2-3 hours ;

d. Heat preservation: adjust the temperature of the high and low temperature constant temperature test box, so that the test core in the physical model mechanism is allowed to stand at a constant temperature of 4°C for 12 to 20 hours, and a highly permeable hydrate deposit is formed in the core holder ;

打开，其它阀门关闭，氮气瓶B中气体经高压调压阀A调压至4MPa，气体压力由压力表A显示，经中压调压阀调压至0.6MPa，气体压力由压力表B显示，再经低压调压阀调压至0.2MPa，气体渗入压力由压力表C显示，进入物理模型机构，通过高流量计测试高渗透性水合物沉积物的渗透率。 e. Air permeability rate: for hyperpermeability experiments, at this time valve ②, valve ④, valve ⑩, valve

Open, other valves are closed, the gas in the nitrogen cylinder B is adjusted to 4MPa by the high-pressure regulator A, the gas pressure is displayed by the pressure gauge A, and the pressure is adjusted to 0.6MPa by the medium-pressure regulator, and the gas pressure is displayed by the pressure gauge B. Then the pressure is adjusted to 0.2MPa by the low-pressure pressure regulating valve, and the gas infiltration pressure is displayed by the pressure gauge C, and enters the physical model mechanism, and the permeability of the high-permeability hydrate deposit is tested by the high-flow meter.

The steps of an experimental method for monitoring the dynamic response characteristics of hydrate deposits during the intrusion of drilling fluid into hydrate deposits according to the present invention are as follows:

(1) The hydrate deposits mentioned above include the hydrate deposits synthesized by using the test core as the skeleton material, and placed in the core holder in the physical model mechanism;

(2) Intrusion of drilling fluid into hydrate deposits: After the drilling fluid in the drilling fluid storage tank is adjusted by the temperature controller to reach the required temperature of 0-50°C for the experiment, it enters the wellhead annular cavity of the physical model mechanism through the drilling fluid circulation pump , and circulate in it, the drilling fluid gradually invades the hydrate deposit in the core holder;

(3) Monitoring the dynamic response during the invasion process: 10 temperature sensors and 10 pressure sensors C, which are uniformly distributed along the core holder axially and fixed on the upper part of the physical model structure, are used to test the hydrate deposits during the invasion process. Changes in temperature and pressure; through 10 resistivity sensors uniformly distributed along the axis of the core holder and fixed at the lower part of the physical model mechanism to test the change in resistivity of hydrate deposits during the invasion process;

(4) Infrared observation: Scan and observe the temperature distribution and change of hydrate deposits in the core holder in the physical model mechanism through the infrared camera installed on the pulley track, and analyze the dynamic invasion process of drilling fluid and the hydrate decomposition area;

(5) Sampling for analysis and research: during the sampling operation, use the hand pump B to pre-increase the pressure at the left end of the piston container B to the same pressure as that in the core holder, and connect the joint of the piston container B to the sampling interface of the physical model mechanism , after connecting, return the hand pump B to the pump, and suck the sample in the core holder into the piston container B;

(6) The software compiled by the industrial computer on the application device is used to collect various data, form a database, analyze and display the response characteristics of natural gas hydrate deposits to drilling fluid invasion.

According to the experimental method for studying the response characteristics of natural gas hydrate formations to drilling fluid invasion described in the present invention, the steps of the method for fidelity transfer of hydrate sediment cores are as follows:

(1) Remove the right end cover of the core holder, and connect the joint of the core transfer mechanism with the right end of the physical model mechanism;

(2) Adjust the temperature in the annular cavity between the outer cavity and the inner cavity of the core transfer mechanism through the temperature controller to reduce the temperature inside the inner cavity, and adjust the pressure inside the inner cavity through the pressure controller;

(3) When the internal temperature and pressure of the inner cavity are the same as those of the core holder, the sealing plate is opened, and the piston is adjusted by the manual pump so that the hydrate sediment core enters the rock under the condition of heat preservation and pressure. core transfer mechanism;

(4) Close the sealing plate in the core transfer mechanism, remove the link between the core transfer mechanism and the physical model mechanism, and realize the fidelity transfer of hydrate deposits.

The present invention has following beneficial effect:

(1) In view of the fact that there is currently no set of experimental devices and experimental methods for comprehensively studying the response characteristics of hydrate formations to drilling fluid invasion in China, the present invention can well make up for this deficiency. The experimental research on the response characteristics of the formation to drilling fluid invasion provides a theoretical basis for the safe and efficient exploration and development of hydrates in the future.

(2) The present invention can test the permeability of the hydrate-containing formation, and grasp the relationship between the permeability and saturation of the hydrate formation and the influence of water and matter decomposition on the permeability of the formation.

(3) In the process of drilling fluid invasion, the present invention combines infrared observation technology with physical parameter monitoring to comprehensively evaluate the dynamic response characteristics of hydrate deposits to drilling fluid invasion.

(4) The present invention can use the core transfer mechanism to realize post-transfer treatment of the hydrate deposits synthesized in the core holder, and conduct correlation research on the drilling fluid invasion and mechanical properties of the hydrate deposits.

(5) The present invention can be used for hydrate scientific experiments and research in relevant scientific research institutes, and provide experimental devices and technical services for safe drilling research for field gas hydrate exploration and development.

Description of drawings

Fig. 1 is a schematic structural diagram of an experimental device for studying the response characteristics of a natural gas hydrate formation to drilling fluid invasion according to the present invention. Fig. 2 is a structural schematic diagram of the core fidelity transfer mechanism of the present invention.

、31-液体水储存容器、32-平流泵、33-活塞容器A、 34-左端盖、35-岩芯夹持器、36-环压腔、37-测试岩芯、38-电阻率传感器、39-压力传感器A、40-高低温恒温实验箱（简称实验箱）、41-环压跟踪泵、42-物理模型机构、43-电子天平、44-右端盖、45-气液分离器、46-气体质量流量计、47-压力传感器B、48-手摇泵A、49-回压阀、50-回压缓冲容器、51-压力表G、52-压力表F、53-压力传感器C、54-温度传感器、55-红外相机、56-手摇泵B、57-活塞容器B、58-取样口、59-井口环空腔、60-滑轮轨道、61-钻井液循环泵、62-外腔体、63-温度控制仪、64-内腔体、 65-活塞 、66-手动泵、 67-环状腔、 68-压力控制仪、 69-封隔板、70-接头。 In the above figure: 1-temperature controller, 2-drilling fluid storage tank, 3-valve ⑦, 4-high pressure regulator B, 5-valve ①, 6-nitrogen cylinder A, 7-low flow meter, 8-pressure Table E, 9-pressure gauge A, 10-high pressure regulator A, 11-valve ②, 12-nitrogen cylinder B, 13-medium pressure regulator, 14-pressure gauge B, 15-valve ③, 16-valve ④, 17-low pressure regulator, 18-pressure gauge C, 19-valve ⑥, 20-valve ⑧, 21-gas booster pump, 22-pressure gauge D, 23-valve ⑤, 24-gas cylinder, 25- Pressure reducing valve, 26-valve⑩, 27-medium flowmeter, 28-high flowmeter, 29-valve⑨, 30-valve

, 31-liquid water storage container, 32-advection pump, 33-piston container A, 34-left end cover, 35-core holder, 36-ring pressure chamber, 37-test core, 38-resistivity sensor, 39-Pressure sensor A, 40-High and low temperature constant temperature test box (abbreviated as test box), 41-Ring pressure tracking pump, 42-Physical model mechanism, 43-Electronic balance, 44-Right end cover, 45-Gas-liquid separator, 46 -Gas mass flowmeter, 47-pressure sensor B, 48-hand pump A, 49-back pressure valve, 50-back pressure buffer container, 51-pressure gauge G, 52-pressure gauge F, 53-pressure sensor C, 54-temperature sensor, 55-infrared camera, 56-hand pump B, 57-piston container B, 58-sampling port, 59-wellhead annular cavity, 60-pulley track, 61-drilling fluid circulation pump, 62-outside Chamber, 63-temperature controller, 64-inner chamber, 65-piston, 66-hand pump, 67-annular chamber, 68-pressure controller, 69-packing plate, 70-connector.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings and embodiments.

Embodiment 1: An experimental device of the present invention for studying the response characteristics of natural gas hydrate formations to drilling fluid invasion, the structure of which is shown in Figure 1 . Including drilling fluid circulation mechanism, test box, core transfer mechanism, gas permeability measurement mechanism, water/gas injection mechanism, ring pressure tracking mechanism, back pressure mechanism, testing mechanism, export metering mechanism, sampling mechanism and industrial computer.

The drilling fluid circulation mechanism includes a temperature controller 1, a drilling fluid storage tank 2, a drilling fluid circulation pump 61 and a wellhead annular cavity 59 of the physical model mechanism 42, wherein the drilling fluid storage tank 2 has a volume of 1000mL, and the temperature is between room temperature and It is controllable and adjustable between -50°C, the maximum injection pressure of the drilling fluid circulation pump 61 is 25MPa, and the flow range is controlled at 0.5-10ml/min.

The high and low temperature constant temperature test box 40 is provided with a physical model mechanism 42, a pulley track 60 and an infrared camera 55: the physical model mechanism is provided with a core holder 35, a ring pressure chamber 36, a left end cover 34, and a right end cover 44 , the wellhead ring cavity 59, the sampling port 58 is located on the upper part of the physical model mechanism; the test core 37 is placed in the core holder 35, and the length of the core holder 35 is 1200mm, which can work safely and corrosion-resistant under 25MPa , In addition, the core can be easily removed. The test rock core 37 adopts an artificial rock core with a specification of φ50mm and a length of 1200mm; the infrared camera 55 is installed on the pulley track 60 inside the high and low temperature constant temperature test box 40, which is aligned with the axis of the physical model mechanism and can move left and right on the pulley track. Obtain the data information in the infrared camera memory card by running the infrared camera association program installed in the industrial computer, and analyze and process to obtain the temperature distribution image, evaluate the dynamic invasion process of the drilling fluid to the hydrate formation and the hydrate decomposition area, and visually observe Combined with data testing, the dynamic response characteristics of hydrate-bearing formations to drilling fluid invasion are analyzed.

30所组成的三种不同渗透压力的管路，分别测试高、中、低三种渗透率的测试岩芯的水合物沉积物渗透性。其中高压调压阀B4和高压调压阀A10的调压范围10～4MPa，中压调压阀13的调压范围4～0.6MPa，低压调压阀17的调压范围0.6～0.2MPa，低流量计7的流量范围30ml/min，中流量计27的流量范围300ml/min，高流量计28的流量范围3000ml/min。 The gas measuring permeability mechanism includes nitrogen cylinder A6, nitrogen cylinder B12, high pressure regulator valve B4 and high pressure regulator valve A 10, medium pressure regulator valve 13, low pressure regulator valve 17, low flow meter 7, medium Flow meter 27 and high flow meter 28, and valve ①5, valve ②11, valve ③15, valve ④16, valve ⑤23, valve ⑥19, valve ⑦3, valve ⑧20, valve ⑨29, valve ⑩26, valve

30 pipelines with three different seepage pressures to test the permeability of hydrate sediments of the test cores with high, medium and low permeability respectively. Among them, the pressure regulating range of high pressure regulating valve B4 and high pressure regulating valve A10 is 10~4MPa, the pressure regulating range of medium pressure regulating valve 13 is 4~0.6MPa, and the pressure regulating range of low pressure regulating valve 17 is 0.6~0.2MPa. The flow range of flow meter 7 is 30ml/min, the flow range of middle flow meter 27 is 300ml/min, and the flow range of high flow meter 28 is 3000ml/min.

30、低流量计7、中流量计27和高流量计28构成。当天然气瓶24压力高于实验所需压力时，天然气由减压阀25减压后注入物理模型机构42，当天然气压力低于实验所需压力时，天然气由气体增压泵20增压后注入物理模型机构，注入气体压力由压力表D22显示。注入物理模型机构中的天然气量在不同渗透性测试岩芯实验时，分别根据低流量计7、中流量计27和高流量计28来确定注入天然气量。 The liquid water injection mechanism and the natural gas injection mechanism, wherein the liquid water injection mechanism is composed of a liquid water storage container 31, an advection pump 32, and a piston container A33. A33 has a volume of 1000ml and a working pressure of 32MPa. The natural gas injection mechanism includes a natural gas cylinder 24, a pressure reducing valve 25, a gas booster pump 21, a pressure gauge D22, a valve ⑤23, a valve ⑦3, a valve ⑥19, a valve ⑧20, a valve ⑨29, a valve ⑩26, and a valve

30, low flow meter 7, middle flow meter 27 and high flow meter 28 constitute. When the pressure of the natural gas bottle 24 is higher than the required pressure of the experiment, the natural gas is decompressed by the pressure reducing valve 25 and then injected into the physical model mechanism 42; The physical model mechanism, the injected gas pressure is displayed by the pressure gauge D22. The amount of natural gas injected into the physical model mechanism is determined according to the low flow meter 7 , the middle flow meter 27 and the high flow meter 28 during different permeability test core experiments.

The ring pressure tracking mechanism is composed of a ring pressure tracking pump 41 and a pressure sensor A39. The ring pressure tracking pump 41 has a cylinder volume of 100 ml, a flow rate adjustable between 0.01 and 30 ml/min, and a maximum ring pressure of 32 MPa. The ring pressure can be maintained in the experiment. The pressure is higher than the internal pressure of the core holder 35 to ensure that the test core 37 is always in a tight state during the experiment.

The back pressure mechanism is composed of a back pressure valve 49, a back pressure buffer container 50, a hand pump A48 and a pressure gauge G51. The back pressure adjustment range of the back pressure valve 49 is 0-25 MPa, and the control fluctuation range is within ±0.1 MPa; The back pressure buffer container 50 has a working pressure of 16MPa and a volume of 500ml; the maximum working pressure of the hand pump A48 is 32MPa.

The temperature measuring mechanism and the pressure measuring mechanism are composed of 10 temperature sensors 54 and 10 pressure sensors C53 which are uniformly distributed along the axial direction of the core holder 35 and fixed on the upper part of the physical model mechanism 42, and the accuracy of the temperature sensors is 0.1°C ;Pressure sensor C precision 0.25%F.S.

The resistivity measuring mechanism is composed of 10 resistivity sensors 38 uniformly distributed along the axial direction of the core holder 35 and fixed on the lower part of the physical model mechanism 42. The measuring range of the resistivity is 0-15000Ω·m, and the accuracy is 1%.

The outlet metering mechanism is composed of a pressure sensor B47, a pressure gauge F52, a gas-liquid separator 45, a gas mass flow meter 46 and an electronic balance 43, and the gas-liquid separator 45 is used for gas and liquid separation at the outlet of the back pressure valve 49. ; The pressure sensor B47 and the pressure gauge F52 are used to monitor the pressure at the outlet; the electronic balance 43 is used for the volume measurement of the outlet liquid, with a range of 4200g and an accuracy of 0.01g; the gas mass flowmeter 46 is used for the volume measurement of the outlet gas, and the flow control range is 0～ 1000ml/min, working pressure 10MPa, can control instantaneous flow and display cumulative flow.

When performing sampling operations, use the hand pump B56 to push the piston in the piston container B57 to the end, connect the joint of the piston container B57 to the sampling interface 58 of the physical model mechanism, and then return the hand pump B56 to the pump to remove the rock. The sample in the core holder is drawn into the plunger container B57.

Referring to Fig. 2, the described rock core fidelity transfer mechanism consists of an outer cavity 62, a temperature controller 63, an inner cavity 64, a piston 65, a manual pump 66, an annular cavity 67, a pressure controller 68, and a packing plate 69. And joint 70 composition. The outer cavity is provided with an inner cavity and an annular cavity. A piston is installed at one end of the inner cavity, and a packing plate is installed at the other end. The joint is installed on the outside of the packing plate. ring connection.

Described industrial computer is a data collection and processing system, and software runs under Windows 2000 or XP environment, is connected with each mechanism through industrial computer, collects values such as pressure, temperature, resistivity, gas and liquid flow in good time and carries out data processing, It can display the parameters of each point in real time and realize man-machine dialogue. After the operator sets the parameters, it can be unattended. The industrial computer automatically collects all parameters and automatically controls the operation of the device. The data collected by the industrial computer can be processed to generate raw data reports, analysis reports and graphs, and at the same time generate a database file format for subsequent data processing and analysis.

Embodiment 2: The present invention proposes a set of experimental methods for studying the response characteristics of natural gas hydrate formations to drilling fluid invasion based on the application of the experimental device of the above-mentioned embodiment 1. The experimental method for testing the gas permeability of hydrate deposits is divided into It is an experimental method for testing the permeability of hydrate sediments with three different permeability: low, medium and high. The specific operation steps are as follows:

(1) The steps of the experimental method for permeability testing of low-permeability hydrate sediments:

a. Water injection: the liquid water in the liquid water storage container 31 is injected into the test rock core 37 in the rock core holder 35 through the advection pump 32 through the piston container A33; the test rock core material adopts a natural rock core with a length of 500mm. The length of 700mm uses a hollow stainless steel cylinder as a fake core to supplement the length to 1200mm to fill the entire core holder;

b. Gas injection: After the liquid water injection is completed, open the natural gas cylinder 24, _CH4 gas passes through the pressure reducing valve 25, when the natural gas pressure is lower than the pressure required for the experiment, open the gas booster pump 21 to increase the pressure, and the gas pressure is measured by the pressure gauge D22 shows that it flows through the valve ⑤23;

c. Select the low-permeability gas injection pipeline, CH4 gas passes through the low-permeability pipeline formed by valve ⑥ 19, valve ⑦ 3, and low flow meter 7, and enters the test rock core 37 in the rock core holder 35, and the pressure in the rock core 37 to be tested reaches Set the pressure at 12MPa and keep it for 2 to 3 hours before stopping the gas injection;

d heat preservation: adjust the temperature of the high and low temperature constant temperature test box 40, so that the test core 37 in the physical model mechanism 42 is allowed to stand at a constant temperature of 4°C for 20 hours, and a low-permeability hydrate deposit is formed in the core holder 35 thing;

e. Permeability measurement by air: low-permeability experiment is carried out. At this time, valve ①5, valve ⑦3, and valve ⑥19 are opened, other valves are closed, and nitrogen cylinder A6 is opened. The nitrogen in the bottle is adjusted to 4MPa by high-pressure regulator B4 and then enters the physical model. Mechanism 42, the gas infiltration pressure is displayed by the pressure gauge E8, and the permeability of the low-permeability hydrate deposit is tested by the low-flow meter 7;

(2) The steps of the experimental method for the permeability test of hydrate sediments with medium permeability:

Steps a and b are the same as the experimental method for low permeability hydrate deposits;

c. Select the medium permeation gas injection pipeline, the natural gas passes through the medium permeation pipeline composed of valve ⑧ 20, medium flow meter 27 and valve ⑨ 29, injects CH4 gas into the test core 37 in the core holder 35, and injects CH4 gas into the core 37 to be tested. Stop gas injection after the pressure reaches the set pressure of 10MPa and maintain for 2 to 3 hours;

d. Heat preservation: adjust the temperature of the high and low temperature constant temperature test box 40, so that the test core 37 in the physical model mechanism 42 is allowed to stand at a constant temperature of 4°C for 18 hours, and a medium-permeability hydrate is formed in the core holder 35 sediment;

e. Permeability measurement by gas: medium infiltration experiment is carried out. At this time, valve ②11, valve ③15, valve ⑧20, and valve ⑨29 are opened, and other valves are closed. It is displayed by the pressure gauge A9, and then adjusted to 0.6MPa by the medium pressure regulator valve 13. The gas pressure is displayed by the pressure gauge B14, and then enters the core holder 35 to test the core 37, and the medium penetration is tested by the medium flow meter 27 Permeability of dry hydrate deposits;

(3) The steps of the experimental method for permeability testing of high permeability hydrate sediments:

Steps a and b are the same as the experimental method for low permeability hydrate deposits;

30、高流量计28所构成的高渗透管路，向岩芯夹持器35中测试岩芯37注入CH4气体，待测试岩芯37中压力达到设定压力8MPa并保持2～3小时后停止注气； c. Select a high-permeability gas injection pipeline, and the natural gas passes through the valve ⑩26, the valve

30. The high-permeability pipeline formed by the high-flow meter 28 injects CH4 gas into the test core 37 in the core holder 35, and stops when the pressure in the test core 37 reaches the set pressure of 8 MPa and keeps for 2 to 3 hours. Gas injection;

d. Heat preservation: adjust the temperature of the high and low temperature constant temperature test box 40, so that the test core 37 in the physical model mechanism 42 is left to stand at a constant temperature of 4°C for 16 hours, and a highly permeable hydrate is formed in the core holder 35 sediment;

30打开，其它阀门关闭，氮气瓶B12中气体经高压调压阀A10调压至4MPa，气体压力由压力表A9显示，经中压调压阀13调压至0.6MPa，气体压力由压力表B14显示，再经低压调压阀17调压至0.2MPa，气体渗入压力由压力表C18显示，进入测试岩芯37，通过高流量计28测试高渗透性水合物沉积物的渗透率。 e. Air permeability rate: for hyperpermeability experiment, at this time valve ②11, valve ④16, valve ⑩26, valve

30 is opened, other valves are closed, the gas in the nitrogen cylinder B12 is adjusted to 4MPa by the high-pressure regulator A10, the gas pressure is displayed by the pressure gauge A9, and the pressure is adjusted to 0.6MPa by the medium-pressure regulator 13, and the gas pressure is controlled by the pressure gauge B14 Display, and then adjust the pressure to 0.2MPa through the low-pressure pressure regulating valve 17, the gas infiltration pressure is displayed by the pressure gauge C18, enter the test core 37, and test the permeability of the high-permeability hydrate deposit through the high-flow meter 28.

Example 3: An experimental method for studying the response characteristics of natural gas hydrate formations to drilling fluid invasion based on the application of the experimental device in Example 1 above, wherein the drilling fluid invades hydrate deposits and the dynamics of hydrate deposits during the invasion process The experimental method steps of response characteristic monitoring are as follows:

(1) Synthesis of hydrate deposits: the length of the core holder 35 is 1200 mm, and the sand filling model is prepared in advance and placed in the core holder 35 to fill the core holder, using the low permeability of Example 2 Steps a and b in the experimental method for the permeability test of hydrate deposits synthesize hydrate deposits;

(2) Intrusion of drilling fluid into hydrate deposits: After the drilling fluid in the drilling fluid storage tank 2 is adjusted to 30°C by the temperature controller 1, it enters the wellhead annular cavity 59 of the physical model mechanism 42 through the drilling fluid circulation pump 61 , and circulate in it, the drilling fluid gradually invades the hydrate deposit in the core holder 35;

(3) Monitoring the dynamic response during the invasion process: 10 temperature sensors 54 and 10 pressure sensors C53 that are uniformly distributed along the core holder 35 axially and fixed on the upper part of the physical model structure 42 are used to test the hydration during the invasion process. Temperature and pressure changes of the hydrate deposits; 10 resistivity sensors 38 uniformly distributed along the axial direction of the core holder 35 and fixed on the lower part of the physical model mechanism 42 are used to test the change of the resistivity of the hydrate deposits during the invasion process;

(4) Infrared observation: scan and observe the temperature distribution and change of hydrate deposits in the core holder in the physical model mechanism 42 through the infrared camera 55 installed on the pulley track 60, and analyze the dynamic invasion process of drilling fluid and hydrate decomposition area;

(5) Sampling for analysis and research: During the sampling operation, use the hand pump B56 to pre-increase a pressure equal to that in the core holder 35 to the left end of the piston container B57, and connect the joint of the piston container B57 to the physical model mechanism 42. After the sampling interface 58 is connected, the hand pump B56 is returned to the pump, and the sample in the core holder 35 is sucked into the piston container B57;

(6) Use the software installed on the industrial computer of the device to collect various data, form a database, analyze and display the response characteristics of natural gas hydrate deposits to drilling fluid invasion.

Embodiment 4: the method for fidelity transfer of the hydrate sediment core in the experimental device of embodiment 1, the specific operation steps are as follows:

(1) Remove the right end cover 44 of the physical model mechanism 42, and connect the joint 70 of the core transfer mechanism with the right end of the physical model mechanism 42;

(2) Adjust the temperature in the annular cavity 67 between the outer cavity 62 and the inner cavity 64 of the core transfer mechanism through the temperature controller 63 to reduce the temperature inside the inner cavity 64, and adjust the inner cavity 64 through the pressure controller 68 internal pressure;

(3) When the internal temperature and pressure of the inner cavity 64 are the same as those of the core holder 35, the sealing plate 69 is opened, and the piston 65 is adjusted by the manual pump 66 so that the hydrate deposits are maintained under the conditions of heat preservation and pressure. Down into the core transfer mechanism;

(4) Close the packing plate 69 in the core transfer mechanism, and remove the link between the core transfer mechanism and the physical model mechanism 42, which realizes the fidelity transfer of hydrate deposits.

Claims (7)

1. study response characteristic is invaded on the gas hydrate stratum to drilling fluid experimental provision for one kind; Comprise circulation of drilling fluid mechanism, high cryogenic thermostat experimental box, perm-plug method mechanism, water/gas injecting mechanism and industrial computer, it is characterized in that: also be provided with core transfer device, ring pressure follower, back pressure mechanism, testing agency, outlet metering mechanism, sampling mechanism;

Described circulation of drilling fluid mechanism is made up of the well head annular space chamber of drilling fluid basin, temperature controller, circulation of drilling fluid pump and physical model mechanism; Temperature controller control drilling fluid temperature, drilling fluid circulates in the hydrate sediment that penetrates in the rock core fastener in the well head annular space chamber of physical model mechanism under the circulation of drilling fluid pumping action;

Described high cryogenic thermostat experimental box is the constant temperature experimental box able to programme of an industrial computer control; Be provided with physical model mechanism in the experimental box; Be provided with drilling fluid well head annular space chamber at physical model mechanism left end, top is provided with a sampling spot, and infrared camera is installed on the pulley track in the experimental box; With physical model mechanism axis alignment, but and move left and right; In physical model mechanism, be provided with rock core fastener, left end cap and right end cap are established in the rock core fastener left and right sides, and the test core is placed in the rock core fastener, rock core fastener axially on be provided with the measuring point of resistivity, pressure, temperature; Physical model mechanism links to each other with perm-plug method mechanism, water/gas injecting mechanism, sampling mechanism with valve, the tensimeter of controlled pressure through the high pressure line of its top, bottom and end; The sensor at ten erect-position measuring point places in the physical model mechanism links to each other with measuring mechanism with pressure duct through signal wire respectively; When shifting the hydrate sediment core that forms in the rock core fastener, the rock core fastener right-hand member linked to each other with the core transfer device realize transfer;

The nitrogen pipeline of three cover different osmotic power, the perviousness of testing high, medium and low three kinds of permeability hydrate sediments are respectively contained in described perm-plug method mechanism; Described water/gas injecting mechanism comprises liquid water injecting mechanism and rock gas injecting mechanism, and the liquid water injecting mechanism is made up of constant-flux pump and piston container; The rock gas injecting mechanism comprises natural gas bottle, reduction valve, gas boosting pump and gas meter, and through the amount of natural gas that gas meter control gets into physical model mechanism, the different saturation hydrate sediment is synthetic in the realization rock core fastener;

Described ring presses follower to press tracking pump and pressure transducer to form by ring, and ring is pressed the pressure differential in chamber and the rock core fastener inner chamber in the tracking physical model mechanism;

Described back pressure mechanism is made up of check valve, back pressure buffer container and backpressure pump; Pressure survey mechanism, resistivity measurement mechanism, flow detection, temperature control and testing agency are contained in said testing agency;

Described outlet metering mechanism is made up of gas-liquid separator, mass-flow gas meter and electronic balance; Described sampling mechanism adopts manual pump and piston sampler, the left end of the piston of piston sampler increase in advance one with physical model mechanism in equal pressure, realize isobaric sampling through moving back pump again;

Described industrial computer moves under Windows 2000 or XP environment, adopts the VB programming, to the collection and the processing of various pressure, temperature, resistivity, gas volume, liquid volume numerical value, controls the operation of each mechanism in good time.

2. the experimental provision of response characteristic is invaded on research gas hydrate according to claim 1 stratum to drilling fluid; It is characterized in that: described rock core fastener is evenly arranged 10 erect-position measuring points on it is axial; Be separately installed with 10 pressure transducer C, 10 temperature sensors and 10 resistivity sensors.

3. the experimental provision of response characteristic is invaded on research gas hydrate according to claim 1 stratum to drilling fluid; It is characterized in that: described rock core fastener specification is φ 50mm; Length 1200mm, test core φ 50mm, length 500～1200mm; The not enough 1200mm of test core length partly mends long through false core, the test core adopts natural core, artificial core or sand-packed model.

4. the experimental provision of response characteristic is invaded on research gas hydrate according to claim 1 stratum to drilling fluid; It is characterized in that: described core fidelity transfer device is made up of outer chamber, inner chamber body, piston, manual pump, ring chamber, temperature controller, pressure controller, packing plate and joint; Outer chamber contains inner chamber body; Inner chamber body one end is equipped with piston, and the other end is equipped with the packing plate, and joint is contained in the packing plate outside; Pressure controller is connected with inner chamber body, and temperature controller is connected with ring chamber.

5. one kind is used to study response characteristic is invaded on the gas hydrate stratum to drilling fluid experimental technique with the described experimental provision of claim 1; Include hydrate sediment gas permeability test experiments method, drilling fluid is to the experimental technique of hydrate sediment dynamic response characteristic monitoring in the intrusion of hydrate sediment and the invasion procedure; Hydrate sediment core fidelity transfer method; It is characterized in that: described hydrate sediment gas permeability test experiments method, be divided into basic, normal, high three kinds of different permeability hydrate sediment testing permeability experimental techniques, concrete steps are following:

(1) step of described low-permeability hydrate sediment testing permeability experimental technique:

A. water filling: the liquid water in the liquid water reservoir vessel passes through constant-flux pump in the piston container A is injected the test core of rock core fastener;

B. gas injection: liquid water is opened natural gas bottle, CH after injecting and finishing ₄Gas when natural atmospheric pressure is lower than the required pressure of experiment, is opened the supercharging of gas boosting pump through reduction valve, and gaseous tension is shown by tensimeter D, flows through valve 5.;

C. select hyposmosis gas injection pipeline, CH ₄Gas through valve 6., valve 7., the hyposmosis pipeline that constitutes of Low-flow meter, get in the rock core fastener and test core, pressure reaches set pressure 8～12MPa and keeps stopping gas injection after 2～3 hours in the core to be tested;

D insulation: regulate the temperature of high cryogenic thermostat experimental box, make that the test core left standstill 12～20 hours in the physical model mechanism under 4 ℃ of constant temperatures, in rock core fastener, form the hydrate sediment of low-permeability;

E. perm-plug method: carry out hypotonic experiment; This moment valve 1., valve 7., 6. valve open; Other valve closing is opened nitrogen cylinder A, and nitrogen gets into physical model mechanism through high-pressure pressure regulating valve B pressure regulation in the bottle to 4MPa; Gas infiltrates pressure and is shown by tensimeter E, through the permeability of Low-flow meter test low-permeability hydrate sediment;

(2) step of described middle perviousness hydrate sediment testing permeability experimental technique:

Step a, b are identical with low-permeability hydrate sediment experimental technique;

C. infiltration gas injection pipeline in selecting, rock gas through valve 8., the middle infiltration pipeline that 9. constitutes of middle flowmeter and valve, the test core injects CH in rock core fastener ₄Gas, pressure reaches set pressure 8～12MPa and keeps stopping gas injection after 2～3 hours in the core to be tested;

D. insulation: regulate the temperature of high cryogenic thermostat experimental box, the test core was left standstill 12～20 hours, infiltrative hydrate sediment in rock core fastener, forming under 4 ℃ of constant temperatures;

E. perm-plug method: ooze experiment in carrying out, this moment valve 2., valve 3., valve 8., 9. valve open other valve closing; Among the nitrogen cylinder B gas earlier through high-pressure pressure regulating valve A pressure regulation to 4MPa; Gaseous tension is shown by tensimeter A, presses the pressure regulator valve pressure regulation to 0.6MPa again in the warp, and gaseous tension is shown by tensimeter B; Get into physical model mechanism then, through the permeability of perviousness hydrate sediment in the middle flowmeter test;

(3) step of described high osmosis hydrate sediment testing permeability experimental technique:

Step a, b are identical with low-permeability hydrate sediment experimental technique;

C. select high infiltration gas injection pipeline, rock gas through valve 10., valve

, the high penetration pipe road that constituted of high flow capacity meter, the test core injects CH in rock core fastener ₄Gas, pressure reaches set pressure 8～12MPa and keeps stopping gas injection after 2～3 hours in the core to be tested;

D. insulation: regulate the temperature of high cryogenic thermostat experimental box, the test core was left standstill 12～20 hours under 4 ℃ of constant temperatures, in rock core fastener, form the hydrate sediment of high osmosis;

E. perm-plug method: carry out height and ooze experiment; This moment valve 2., valve 4., valve 10., valve

opens; Other valve closing, to 4MPa, gaseous tension is shown by tensimeter A gas through high-pressure pressure regulating valve A pressure regulation among the nitrogen cylinder B; Press the pressure regulator valve pressure regulation to 0.6MPa in the warp; Gaseous tension shows by tensimeter B, again through the low pressure regulating pressure valve pressure regulation to 0.2MPa, gas infiltrates pressure and is shown by tensimeter C; Get into physical model mechanism, through the permeability of high flow capacity instrumentation examination high osmosis hydrate sediment.

6. according to claim 5ly be used to study the gas hydrate stratum drilling fluid is invaded the experimental technique of response characteristic, it is characterized in that: described drilling fluid is following to the experimental technique step of hydrate sediment dynamic response characteristic monitoring in the intrusion of hydrate sediment and the invasion procedure:

(1) described hydrate sediment comprises that utilization test core as the synthetic hydrate sediment of framework material, is placed in the in-house core holding unit of physical model;

(2) drilling fluid is to the intrusion of hydrate sediment: the drilling fluid in the drilling fluid storage tank through temperature controller regulate reach 0～50 ℃ of experiment demand temperature after; Get into the well head annular space chamber of physical model mechanism through the circulation of drilling fluid pump; And circulated therein flows, and drilling fluid is gradually in the irruptive rock core holder in the hydrate sediment;

(3) dynamic response of monitoring in the invasion procedure: respectively through axially being uniformly distributed with along rock core fastener and being fixed in 10 temperature sensors on physical model structure top and temperature and pressure that 10 pressure transducer C test hydrate sediment in the invasion procedure changes; Through axially be uniformly distributed with and be fixed in the variation of hydrate sediment resistivity in 10 resistivity sensors test invasion procedures of physical model mechanism bottom along rock core fastener;

(4) infrared observation: the phase of infrared camera scanning through being installed on the pulley track is observed the Temperature Distribution and the variation of hydrate sediment in the rock core fastener in the physical model mechanism, analyzes dynamic invasion procedure of drilling fluid and decomposition of hydrate zone;

(5) sampling analyze and research: during sampling operation with wobble pump B to piston container B left end increase in advance one with rock core fastener in identical pressure; The joint of piston container B is connected to the sample connection of physical model mechanism; After connecting; Wobble pump B is moved back pump handle, in the sample sucker container B in the rock core fastener;

(6) software of the establishment of the industrial computer on the application apparatus carries out the collection of various data, forms database, and analysis also shows the response characteristic that the gas hydrate sediment is invaded drilling fluid.

7. according to claim 5ly be used to study the gas hydrate stratum drilling fluid is invaded the experimental technique of response characteristic, it is characterized in that: described hydrate sediment core fidelity transfer method step is following:

(1) unloads the right end cap of rock core fastener, the joint of core transfer device is connected with physical model mechanism right-hand member;

(2) regulate between core transfer device outer chamber and inner chamber body the temperature in the ring chamber through temperature controller and regulate the inner chamber body pressure inside through pressure controller to reduce the inner chamber body temperature inside;

(3), make the hydrate sediment core under the condition of heat-insulation pressure keeping, get into the core transfer device through the manual pump regulating piston when inner chamber body internal temperature, pressure and rock core fastener internal temperature, when pressure is identical, open the packing plate;

(4) close packing plate in the core transfer device, unload linking of core transfer device and physical model mechanism, realize that the fidelity of hydrate sediment shifts.

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