CN104950074B - Experimental method and experimental device for measuring sand production caused by hydrate decomposition seepage - Google Patents

Abstract

The invention provides an experimental method and experimental device for measuring sand production caused by hydrate decomposition and seepage, comprising the following steps: filling the sample tube with experimental materials to simulate the hydrate deposition layer; placing the sample tube at 8-30 MPa, 0 ~10°C environment; fill the sample tube with methane gas and water to simulate hydrate decomposition and production; simulate hydrate decomposition seepage through a filter, and the water-sand-gas mixture in the sample tube passes through the filter The mixture of methane gas, water and part of the sand flows out; the methane gas flows upward through the flowmeter and obtains the volume, and the water-sand mixture flows downward through the NMR measurement module to obtain the volume of the sand. The invention can measure the temperature and pressure, sand output, gas output and water output in the process of hydrate decomposition and seepage in real time, and provide scientific basis and technical support for the prediction of sand output in hydrate mining and the formulation of prevention and control measures.

Description

Experimental method and experimental device for measuring sand production caused by hydrate decomposition seepage

technical field

The invention relates to natural gas hydrate exploitation technology, in particular to an experimental method and an experimental device for measuring sand production caused by hydrate decomposition seepage.

Background technique

Natural gas hydrate is an unconventional energy resource with huge reserves and clean energy, and it is also one of my country's strategic energy sources. Internationally, in the process of gas hydrate trial production, the problem of sand production after hydrate decomposition is serious, causing disasters such as production reduction, suspension of trial production, and wellbore instability. , Multi-field and multi-phase coupling problems of skeleton deformation, but there is still a lack of research in this area. Therefore, the present invention proposes an experimental device and an experimental method for measuring sand production caused by hydrate decomposition seepage.

Contents of the invention

The invention provides an experimental method and experimental device for measuring sand production caused by hydrate decomposition and seepage, which are used to overcome the defects in the prior art and measure temperature, pressure, sand production, gas production and gas production in real time during the process of hydrate decomposition and seepage. Provide scientific basis and technical support for the prediction of sand production in hydrate mining and the formulation of prevention and control measures.

The invention provides an experimental method for measuring sand production caused by hydrate decomposition and seepage, comprising the following steps:

Step 1, filling the sample tube with the experimental material to simulate the deposition layer;

Step 2, placing the sample tube in an environment of 8-30 MPa and 0-10°C to simulate the preparation of a hydrate deposition layer;

Step 3, filling the sample tube with methane gas and water, and at the same time causing the hydrate to decompose and flow, so as to simulate the production of hydrate;

Step 4, simulating the bottom hole production section through a filter screen, the water-sand-gas mixture in the sample tube passes through the filter screen, and the methane gas, water and part of the sand mixture flow out;

In step 5, the methane gas flows upward through the flowmeter to obtain the volume, and the water-sand mixture flows downward through the nuclear magnetic resonance measurement module to obtain the volume of the sand.

Wherein, the experimental materials are sand or clay with different particle gradations.

Preferably, hydrate decomposition is simulated by means of heat injection, depressurization or a combination of the two.

Preferably, during the process of simulating hydrate decomposition, the temperature and pressure change data along the length direction of the sample tube are measured.

The present invention also provides an experimental device for measuring sand production caused by hydrate decomposition seepage, including:

The sample tube is placed in a closed container for containing experimental materials and simulating the hydrate deposition layer. The inlet end is connected to the gas supply and liquid supply module, and the outlet end is connected to the filter screen. Temperature sensors and pressure sensors are arranged on the surrounding wall;

The airtight container is filled with a loading medium between the airtight container and the sample tube, and is sealed between the sample tube and the airtight container;

The confining pressure loading module is connected to the airtight container, and applies pressure to the inside of the airtight container through the loading medium;

The gas supply and liquid supply module is used to feed methane gas and water into the sample tube to simulate the preparation of hydrate deposits;

The filter screen is used to simulate sand production caused by hydrate decomposition seepage;

A flow meter, used to measure the volume of methane gas, is installed on the upper branch pipe, and the upper branch pipe is connected to the outlet end of the sample tube;

The nuclear magnetic resonance measurement module is used to measure the total weight of the water-sand mixture flowing out through the filter screen and the volume of water therein, and is installed on the lower branch pipe, and the lower branch pipe is connected to the outlet end of the sample tube.

Preferably, the air supply and liquid supply module includes:

An autoclave, internally provided with a piston that divides the interior of the autoclave into two cavities, and the piston can move inside the autoclave under the action of an external force;

One of the cavities is connected to the inlet end of the sample tube, filled with methane gas and water, and equipped with a stirrer for fully mixing the gas and liquid; the other cavity is filled with hydraulic oil, and is connected with the hydraulic loading system connected.

Preferably, the sample tube is provided with a plurality of small holes along the length direction, and temperature sensors or pressure sensors are installed on the small holes.

Preferably, the loading medium filled between the airtight container and the sample tube is hydraulic oil or antifreeze, and the confining pressure loading module is a pump or a hydraulic loading system.

Preferably, a pressure chamber for buffering pressure shock is also provided between the lower branch pipe and the nuclear magnetic resonance measurement module.

The experimental method and experimental device for measuring sand production caused by hydrate decomposition and seepage provided by the present invention can measure the temperature and pressure, sand production, gas production and water production during the process of hydrate decomposition and seepage in real time, and provide sand production prediction and analysis for hydrate mining. The formulation of prevention and control measures provides scientific basis and technical support. The invention provides a new experimental system and testing technology for hydrate mining and sand production. It also has potential application value in engineering and technical fields such as heat and mass transfer and fine particle migration.

Description of drawings

Figure 1 is a schematic diagram of the overall structure of the experimental device for sand production measurement caused by hydrate decomposition seepage provided by the embodiment of the present invention;

Fig. 2 is a schematic structural diagram of the gas supply and liquid supply modules in the experimental device for the measurement of sand production caused by hydrate decomposition and seepage provided in the embodiment of the present invention.

detailed description

Referring to Fig. 1 and Fig. 2, an embodiment of the present invention provides an experimental method for measuring sand production caused by hydrate decomposition seepage, which includes the following steps:

Step 1, fill the sample tube 1 with experimental materials to prepare a simulated hydrate deposition layer; the room temperature is controlled at -20°C to 50°C, the diameter of the sample tube is 4cm, and the length is 100cm; the experimental materials can be sand or clay with different particle gradations .

Step 2, place the sample tube 1 in an environment of 8MPa-30MPa, 0°C-10°C (preferably 2°C-10°C) to simulate the preparation and decomposition of hydrate; specifically, set the sample tube 1 in a closed container 2 , and are sealed with each other, the sample tube 1 and the airtight container 2 are filled with a loading medium, the loading medium can be hydraulic oil or antifreeze, and the airtight container 2 is connected with a confining pressure loading system 3 for passing the loading medium Apply pressure to the sample tube. The sample tube 1 is usually made of a material with strong plasticity such as rubber, which is easy to deform, and transmits the pressure from the loading medium to the hydrate deposition layer inside it. The confining pressure loading system 3 can be a pump or Hydraulic loading system. Hydrates can be decomposed and seeped through heating or depressurization or a combination of both.

Step 3, fill the sample tube 1 with methane gas and water to simulate the exploitation of hydrate; specifically, the gas-liquid mixture at constant pressure is injected into the hydrate deposit layer in the sample tube 1 through the gas supply and liquid supply module 4, and the gas supply The liquid supply module is composed of a hydraulic loading system, a pressure kettle, a piston, and an agitator. The agitator makes the gas and liquid fully mixed, and then the pressure-adjustable fluid drives the piston in the pressure kettle to ensure a constant pressure of the gas-liquid mixed fluid in the pressure kettle. layer of deposits.

Step 4, simulating hydrate decomposition seepage through the filter screen 5, the water-sand gas mixture in the sample tube 1 passes through the filter screen 5, and then the methane gas, water and part of the sand mixture flow out; the filter screen has a diameter of 4 cm and a thickness of 1 cm, and the filter screen 5 can be The sand particles in the sediment layer are arranged in different numbers and pore sizes (0.1mm-2.0mm), allowing some particles of sand to flow out. The outflowing water-sand-gas mixture is separated at the filter port, and the dense water-sand flows downward. Gases with low density flow upward;

Step 5, methane gas flows upwards through the upper branch pipe 6 through the flowmeter 7 to obtain volume, and the water-sand mixture flows downward through the lower branch pipe 8 through the nuclear magnetic resonance measurement module 9 to obtain the volume of water.

One real-time sample from NMR measurement module 9 can be taken at an interval of 15 minutes, and the diameter and distribution of sand particles can be measured under an electron microscope. These data are used for macro and micro analysis of sand production caused by hydrate decomposition seepage.

Measure the volume of water and sand after hydrate decomposition, wherein the volume of water is measured by the nuclear magnetic resonance measurement module 9, the volume of water-sand mixing is calculated from the weight change of the water-sand receiving container, and the volume of water-sand mixing minus the volume of water is is the volume of sand; in order to obtain dry methane gas, a gas drying system 10 with a length of 0.5m to 1m can be installed on the upper branch pipe, and the dry methane gas can measure the gas volume through flow meter 7; The pressure of the sand mixture is relatively high. In order to buffer the impact of the pressure on the nuclear magnetic resonance measurement module 9, a pressure chamber 91 can be set on the lower branch pipe. The pressure chamber can be made of polyester material to avoid nuclear magnetic interference.

During the process of simulating hydrate decomposition, the temperature and pressure change data along the length direction of the sample tube 1 are respectively measured by the temperature sensor 11 and the pressure sensor 12 installed on the sample tube 1 .

The embodiment of the present invention also provides an experimental device for measuring sand production caused by hydrate decomposition seepage, see Figure 1 and Figure 2, including:

The sample tube 1 is placed in an airtight container 2 for containing experimental materials and simulating the hydrate deposition layer. The inlet end is connected to the gas supply and liquid supply module 4, and the outlet end is connected to the filter screen 5. A temperature sensor 11 is arranged on the wall of the sample tube 1 and pressure sensor 12;

An airtight container 2, filled with a loading medium between the airtight container 2 and the sample tube 1, and sealed between the sample tube 1 and the airtight container 2;

The confining pressure loading module 3 is connected to the airtight container, and applies pressure to the inside of the airtight container 2 through the loading medium; the loading medium filled between the airtight container 2 and the sample tube 1 is hydraulic oil or antifreeze, and the confining pressure loading module 3 is pump or hydraulic loading system;

The gas supply and liquid supply module 4 is used to feed methane gas and water into the sample tube to simulate hydrate decomposition;

The filter screen 5 is used to simulate the sand production caused by hydrate decomposition seepage;

Flow meter 6, used to measure the volume of methane gas, is installed on the upper branch pipe 7, and the upper branch pipe 7 is connected to the outlet end of the sample pipe 1;

The nuclear magnetic resonance measurement module 9 is used to measure the total weight of the water-sand mixture flowing out through the filter screen 5 and the volume of water therein, and is installed on the lower branch pipe 8, which is connected to the outlet end of the sample pipe 1.

The air supply and liquid supply module 4 includes:

An autoclave 41 is internally provided with a piston 42 that divides the interior of the autoclave into two cavities, and the piston 42 can move inside the autoclave under the action of an external force;

One of the cavities is connected to the inlet end of the sample tube, filled with methane gas and water, and is provided with a stirrer 43 for fully mixing the gas and liquid inside, and the cavity is provided with a first inlet 41a for adding methane gas. The second inlet 41b for adding water and the outlet 41c for spraying gas and liquid; the other cavity is filled with hydraulic oil and communicates with the hydraulic loading system 20, and the cavity communicates with the interior of the hydraulic loading system. See Figure 2.

The hydraulic loading system 20 is used to apply pressure to the hydraulic oil in one of the cavities and push the piston so that the gas-liquid mixture in the other cavity has a constant pressure, and the hydraulic oil pressure inside the hydraulic loading system 20 can be adjusted as required. A valve 40 may be provided between the gas supply and liquid supply module 4 and the sample tube 1 to facilitate experimental operation and pressure adjustment. See Figure 1.

The sample tube 1 is provided with a plurality of small holes along the length direction, and a temperature sensor 11 or a pressure sensor 12 is installed on the small holes.

The invention can measure the temperature and pressure, sand output, gas output and water output in the process of hydrate decomposition and seepage in real time, and provide scientific basis and technical support for the prediction of sand output in hydrate mining and the formulation of prevention and control measures. The invention provides a new experimental system and testing technology for hydrate mining and sand production, and also has potential application value in engineering and technical fields such as heat and mass transfer, fine particle migration, and the like.

Claims (9)

1. a decomposition of hydrate seepage flow causes the experimental provision measured that shakes out, it is characterised in that including:

Sample cell, is placed in hermetic container, is used for accommodating experiment material, simulating hydrate sedimentary, enters Mouth end connects supply feed flow module, and the port of export connects filter screen, perisporium is provided with temperature sensor and pressure Sensor；

Hermetic container, is filled with loaded medium between described hermetic container and described sample cell, and described Seal between sample cell and described hermetic container；

Confined pressure load-on module, is connected with hermetic container, and by described loaded medium to described airtight appearance Device is internal applies pressure；

Described supply feed flow module, for being passed through methane gas and water, with simulation in described sample cell Decomposition of hydrate；

Described filter screen, for shaking out that simulating hydrate decomposition seepage flow causes；

Effusion meter, for measuring the volume of methane gas, is arranged on arm, and described upper arm is even Connect the port of export of described sample cell；

Nuclear Magnetic Resonance Measurement module, for measuring the gross weight of water sand mixture and its flowed out through filter screen The volume of middle water, is arranged on lower branch line, and described lower branch line connects the port of export of described sample cell.

Decomposition of hydrate seepage flow the most according to claim 1 causes the experimental provision measured that shakes out, It is characterized in that, described supply feed flow module includes:

Autoclave pressure, is internally provided with the piston by being divided into two cavitys inside described autoclave pressure, described work Plug can move under external force inside described autoclave pressure；

One of them cavity is connected with the arrival end of described sample cell, is inside filled with methane gas and water, It is internally provided with for making the well-mixed agitator of gas-liquid；It is filled with hydraulic oil in another cavity, And connect with hydraulic loading system.

Decomposition of hydrate seepage flow the most according to claim 2 causes the experimental provision measured that shakes out, It is characterized in that, described sample cell is provided with multiple aperture along its length, described aperture is provided with Temperature sensor or pressure transducer.

4. cause, according to the arbitrary described decomposition of hydrate seepage flow of claim 1-3, the experiment measured of shaking out Device, it is characterised in that being filled in the loaded medium between described hermetic container and described sample cell is liquid Force feed or anti-icing fluid, described confined pressure load-on module is pump or hydraulic loading system.

Decomposition of hydrate seepage flow the most according to claim 4 causes the experimental provision measured that shakes out, It is characterized in that, be additionally provided with for buffering pressure between described lower branch line and described Nuclear Magnetic Resonance Measurement module Power surge room.

6. one kind uses decomposition of hydrate seepage flow as claimed in claim 2 to cause the experiment dress measured that shakes out The decomposition of hydrate seepage flow put causes the experimental technique measured that shakes out, it is characterised in that comprise the following steps:

Step 1, fills experiment material, simulating hydrate sedimentary in sample cell；

Step 2, is placed on described sample cell in the environment of 8～30MPa, 0～10 DEG C, simulating hydrate Preparation and decomposition；

Step 3, fills methane gas and water in described sample cell, with the exploitation of simulating hydrate；

Step 4, by filter screen simulating hydrate decomposition seepage flow, the water sand gas mixture in described sample cell After filter screen, methane gas, water flow out with part sand mixture；

Step 5, methane gas flows up through effusion meter and obtains volume, and water sand mixture flows downwardly through core Magnetic resonance measurement module also obtains the volume of sand.

Decomposition of hydrate seepage flow the most according to claim 6 causes the experimental technique measured that shakes out, It is characterized in that, described experiment material is sand or the clay of variable grain grating.

Decomposition of hydrate seepage flow the most according to claim 7 causes the experimental technique measured that shakes out, It is characterized in that, use heat injection, blood pressure lowering or both united mode simulating hydrate decomposition.

Decomposition of hydrate seepage flow the most according to claim 8 causes the experimental technique measured that shakes out, It is characterized in that, during simulating hydrate decomposition, measure the temperature of described sample cell length direction With pressure delta data.