CN111912757A - Mud shale parameter measurement device - Google Patents

Abstract

The invention discloses a shale parameter measuring device, and belongs to the technical field of oil and gas field development. The device comprises: the device comprises a core holder, an upstream fluid storage tank, a testing liquid storage tank, a downstream fluid storage tank, a confining pressure pump, a confining pressure storage tank and an axial pressure pump, wherein the core holder is positioned in a constant temperature box, the upstream fluid storage tank is respectively connected with an upstream pump and the core holder, the testing liquid storage tank is respectively connected with the upstream pump and the core holder, the downstream fluid storage tank is respectively connected with a downstream pump and the core holder, the confining pressure pump is communicated with a confining pressure cavity inside the core holder, the confining pressure storage tank is communicated with a confining pressure cavity inside the core holder, and the axial pressure. The core holder comprises an outer barrel, an upper plug and a lower plug which are connected with the outer barrel, an upper fluid pipe connected with the upper plug, a lower fluid pipe connected with the lower plug and a rubber barrel which is axially positioned between the upper plug and the lower plug. The device provided by the invention can be used for performing mutually independent liquid circulation at the upstream end and the downstream end of the shale core, so that the accuracy of shale parameter measurement is improved.

Description

Mud shale parameter measurement device

technical field

The invention relates to the technical field of oil and gas field development, in particular to a shale parameter measuring device.

Background technique

With the gradual deepening of oil and gas field development, the exploitation of unconventional oil and gas reservoirs is also increasing. As a kind of unconventional oil and gas reservoirs, mud shale reservoirs have received extensive attention in recent years. Among them, the wellbore stability of mud shale reservoirs is the main factor affecting the mining speed and cost of mud shale reservoirs. Therefore, it is necessary to evaluate the wellbore stability of mud shale reservoirs.

At present, related technologies mainly use the permeability and membrane efficiency of shale as evaluation indicators to evaluate the wellbore stability of shale reservoirs. Therefore, it is necessary to provide a shale parameter measuring device, which can accurately measure the permeability and membrane efficiency of shale.

SUMMARY OF THE INVENTION

The embodiment of the present invention provides a shale parameter measuring device, so as to accurately measure the permeability and membrane efficiency of shale. The technical solution is as follows:

Provided is a mud shale parameter measurement device, the device includes: a core holder, a constant temperature box, an upstream fluid storage tank, a test fluid storage tank, an upstream pump, a downstream fluid storage tank, a downstream pump, a confining pressure pump, a confining pressure storage tanks and axial pressure pumps;

Wherein, the core holder is located in the constant temperature box, and the inlet end of the upstream fluid storage tank, the inlet end of the test fluid storage tank and the outlet end of the upstream pump are connected through an inlet three-way valve, so The outlet end of the upstream fluid storage tank, the outlet end of the test fluid storage tank and the upper inlet end of the core holder are connected through an outlet three-way valve, and the outlet three-way valve is connected to the core holder There is an upstream pressure transmitter between the upper inlet ends of the core holders, the upper outlet end of the core holder is connected to the outside of the incubator; the inlet end of the downstream fluid storage tank is connected to the outlet end of the downstream pump, The outlet end of the downstream fluid storage tank is connected with the lower inlet end of the core holder, and there is a downstream pressure transmitter between the downstream fluid storage tank and the lower inlet end of the core holder, so the lower outlet end of the core holder communicates with the outside of the incubator;

The confining pressure pump and the confining pressure storage tank are all communicated with the confining pressure cavity inside the core holder, and there is a confining pressure transmitter between the confining pressure pump and the confining pressure cavity; The outlet end of the axial pressure pump is communicated with the axial pressure cavity inside the core holder, and an axial pressure pressure transmitter is arranged between the axial pressure pump and the axial pressure cavity;

The core holder includes an outer cylinder, a lower plug, a lower fluid pipe, an upper plug, an upper fluid pipe and a rubber cylinder;

The lower plug and the upper plug are both connected to the outer cylinder, the lower fluid pipe is connected to the lower plug, the upper fluid pipe is connected to the upper plug, and the rubber cylinder shaft between the lower plug and the upper plug.

Optionally, the outer cylinder includes a top cover and a side wall, the lower plug includes a base, a sliding seat and a second boss that are connected in sequence from bottom to top, the side wall is connected to the base, and the side wall is connected to the base. The inner wall of the wall, the upper end face of the base, the outer wall of the sliding seat, the outer wall of the rubber cylinder and the lower end face of the upper plug enclose the confining pressure cavity;

The interior of the base is the axial pressure cavity, the base is provided with a connection hole penetrating the upper end surface of the base, and the diameter of the connection hole is equal to the outer diameter of the sliding seat;

The sliding seat can move up and down along the connecting hole, and the sliding seat has a lower inlet channel and a lower outlet channel passing through the sliding seat. The lower fluid pipes are connected to each other, and the second boss is located on the upper end face of the sliding seat;

The outer diameter of the upper plug is equal to the inner diameter of the side wall, the lower end surface of the upper plug is provided with a first boss, and the upper plug has an upper inlet channel and an upper outlet passing through the upper plug a channel, the upper inlet channel and the upper outlet channel are respectively connected with an upper fluid pipe running through the base;

The two axial ends of the rubber cylinder are respectively sleeved on the first boss and the second boss.

Optionally, the core holder further includes: a first displacement transmitter; the first displacement transmitter is connected to the sliding seat.

Optionally, the outer cylinder includes a side wall and a bottom cover, the upper plug includes a top seat, a sliding seat and a second boss that are connected in sequence from top to bottom, and the side wall is connected to the top seat, The inner wall of the side wall, the lower end face of the top seat, the outer wall of the sliding seat, the outer wall of the rubber cylinder and the upper end face of the lower plug enclose the confining pressure cavity;

The inside of the top seat is the axial pressure cavity, the top seat is provided with a connecting hole penetrating the lower end surface of the top seat, and the diameter of the connecting hole is equal to the diameter of the sliding seat;

The sliding seat can move up and down along the connecting hole, and the sliding seat has an upper inlet channel and an upper outlet channel passing through the sliding seat. The upper fluid pipes of the seat are connected, and the second boss is located on the lower end surface of the sliding seat;

The outer diameter of the lower plug is equal to the inner diameter of the side wall, the upper end face of the lower plug is provided with a first boss, and the lower plug has a lower inlet channel and a lower outlet passing through the lower plug a channel, the lower inlet channel and the lower outlet channel are respectively connected with a lower fluid pipe penetrating the top seat;

The two axial ends of the rubber cylinder are respectively sleeved on the first boss and the second boss.

Further, the core holder further comprises: a second displacement transmitter; the second displacement transmitter is connected with the lower plug.

Optionally, the core holder further comprises: a backing ring; the outer diameter of the backing ring is the same as the inner diameter of the rubber cylinder, and the backing ring is axially located on the upper plug to clamp the core between the cores held by the device.

Optionally, the core holder further includes: a temperature measuring probe; the temperature measuring probe is connected to the inner wall of the outer cylinder, and the temperature measuring probe is located in the confining pressure cavity.

Optionally, the downstream fluid storage tank is connected to the upstream fluid storage tank.

Optionally, a pressure guiding pipeline is arranged between the upstream pressure transmitter and the downstream pressure transmitter, and a differential pressure transmitter is arranged on the pressure guiding pipeline.

Optionally, the upstream fluid storage tank, the test liquid storage tank and the downstream fluid storage tank are all piston-type containers.

The beneficial effects brought by the technical solution provided by the present invention at least include:

The core holder provided by the embodiment of the present invention has an upper inlet end, an upper outlet end, a lower inlet end and a lower outlet end, and liquid circulates at the upstream end of the core through the upper inlet end and the upper outlet end, and passes through the lower inlet end and the lower outlet end. The outlet end performs liquid circulation at the downstream end of the core. Since the liquid circulation at the upstream and downstream ends of the core is independent and does not interfere with each other, the accuracy of shale parameter measurement is improved.

Description of drawings

In order to illustrate the technical solutions in the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings used in the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative effort.

1 is a schematic structural diagram of a shale parameter measuring device provided by an embodiment of the present invention;

2 is a schematic structural diagram of a core holder provided by an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of a lower plug provided by an embodiment of the present invention.

Wherein, each label in the accompanying drawing is described as follows:

1 core holder, 101 outer barrel, 102 lower plug, 103 lower fluid tube, 104 upper plug, 105 upper fluid tube, 106 rubber barrel, 2 incubator, 3 upstream fluid storage tank, 4 test fluid storage tank, 5 upstream pump, 6 downstream fluid storage tank, 7 downstream pump, 8 confining pressure pump, 9 confining pressure storage tank, 10 axial pressure pump.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

An embodiment of the present invention provides a shale parameter measurement device. As shown in FIG. 1 , the device includes: a core holder 1 , a constant temperature box 2 , an upstream fluid storage tank 3 , a test fluid storage tank 4 , and an upstream pump 5 , downstream fluid storage tank 6 , downstream pump 7 , confining pressure pump 8 , confining pressure storage tank 9 and axial pressure pump 10 .

The core holder 1 is located in the incubator 2, the inlet end of the upstream fluid storage tank 3, the inlet end of the test liquid storage tank 4 and the outlet end of the upstream pump 5 are connected through an inlet three-way valve, and the outlet end of the upstream fluid storage tank 3 is connected. , The outlet end of the test liquid storage tank is connected with the upper inlet channel inside the upper plug 104 through the outlet three-way valve, and there is an upstream pressure transmitter on the pipeline between the outlet three-way valve and the upper plug 104, and the core is clamped The upper outlet end of the device 1 is communicated with the outside of the incubator 2; the inlet end of the downstream fluid storage tank 6 is connected with the outlet end of the downstream pump 7, and the outlet end of the downstream fluid storage tank 6 is connected with the lower inlet channel inside the lower plug 102, In addition, there is a downstream pressure transmitter on the pipeline between the downstream fluid storage tank 6 and the lower plug 102 , and the lower outlet end of the core holder 1 communicates with the outside of the incubator 2 .

The confining pressure pump 8 and the confining pressure storage tank 9 are all communicated with the confining pressure cavity. There is a confining pressure transmitter on the pipeline between the confining pressure pump 8 and the confining pressure cavity, and the confining pressure storage tank 9 has a gas injection pipeline. ; The outlet end of the axial pressure pump 10 is communicated with the axial pressure cavity, and there is an axial pressure pressure transmitter on the pipeline between the axial pressure pump 10 and the axial pressure cavity.

The core holder 1 includes an outer cylinder 101, a lower plug 102, a lower fluid pipe 103, an upper plug 104, an upper fluid pipe 105 and a rubber cylinder 106; the lower plug 102 and the upper plug 104 are both connected to the outer cylinder 101, The lower fluid pipe 103 is connected to the lower plug 102 , the upper fluid pipe 105 is connected to the upper plug 104 , and the rubber cylinder 106 is axially located between the lower plug 102 and the upper plug 104 .

In this embodiment, the core holder 1 is suitable for a core with a diameter of 25 mm (unit: millimeter) and an axial length of 25-80 mm.

The upstream pressure transmitter, downstream pressure transmitter, confining pressure transmitter and axial pressure transmitter all use DBY-300 pressure transmitter, the pressure transmitter range is 150MPa (unit: MPa) , the accuracy is 0.25% F · S (FullScale, full scale).

Optionally, as shown in FIG. 2 , the core holder 1 includes the outer cylinder 101 , the lower plug 102 , the lower fluid pipe 103 , the upper plug 104 , the upper fluid pipe 105 and the rubber cylinder 106 . The connection method includes: the outer cylinder 101 includes a top cover and a side wall, the lower plug 102 includes a connected base, a sliding seat and a second boss in order from bottom to top, the side wall is connected with the base, the inner wall of the side wall, the upper part of the base. The end face, the outer wall of the sliding seat, the outer wall of the rubber cylinder 106 and the lower end face of the upper plug 104 enclose a pressure-entraining cavity.

The interior of the base is an axial pressure cavity, and the base has a connecting hole that penetrates the upper end face of the base. The diameter of the connecting hole is equal to the outer diameter of the sliding seat; the sliding seat can move up and down along the connecting hole, and the sliding seat has a lower part that penetrates the sliding seat. The inlet channel and the lower outlet channel are respectively connected with a lower fluid pipe 103 penetrating the base, and the second boss is located on the upper end surface of the sliding seat.

The outer diameter of the upper plug 104 is equal to the inner diameter of the side wall, the lower end face of the upper plug 104 has a first boss, the upper plug 104 has an upper inlet channel and an upper outlet channel that penetrate the upper plug 104, and the upper inlet channel and The upper outlet channels are respectively connected with an upper fluid pipe 105 penetrating the base. Two axial ends of the rubber cylinder 106 are respectively sleeved on the first boss and the second boss.

It should be noted that, in the first connection manner, a schematic structural diagram of the lower plug 102 can be seen in FIG. 3 . The base included in the lower plug 102 and the outer cylinder 101 can be connected by threads, for example, the outer wall of the base has an outer thread, and the inner wall of the outer cylinder 101 has an inner thread that engages with the outer thread. The connection between the lower plug 102 and the outer cylinder 101 may further include a sealing member to improve the sealing performance of the core holder 1 . The upper plug 104 is in contact with the inner wall of the outer cylinder 101 , and the connection between the upper plug 104 and the outer cylinder 101 is a detachable movable connection.

In addition, the upper fluid pipe 105 connected to the upper inlet channel and the upper outlet channel can not only penetrate through the base, but also penetrate through the base and the sliding seat, which is not limited in this embodiment.

In this embodiment, the core holder 1 further includes a first displacement transmitter, and the first displacement transmitter is connected to the sliding seat included in the lower plug 102, so as to adjust the movement of the sliding seat included in the lower plug 102. Displacement distance is measured. For example, LVDT (Linear Variable Differential Transformer, Linear Variable Differential Transformer) with model THGA-10 can be selected, that is, a linear displacement sensor, with a withstand voltage of 40MPa, a temperature resistance of 150°C, and a measurement range of 0 to 10mm.

In an optional embodiment, the outer cylinder 101 , the lower plug 102 , the lower fluid pipe 103 , the upper plug 104 , the upper fluid pipe 105 and the rubber cylinder 106 included in the core holder 1 can also pass through The second connection method is connected. The second connection method includes: the outer cylinder 101 includes a side wall and a bottom cover, the upper plug 104 includes a top seat, a sliding seat and a second boss that are connected in sequence from top to bottom, the side wall is connected to the top seat, and the side wall is connected to the top seat. The inner wall, the lower end surface of the top seat, the outer wall of the sliding seat, the outer wall of the rubber cylinder 106 and the upper end surface of the lower plug 102 enclose an enclosed pressure cavity.

The inside of the top seat is an axial pressure cavity, and the top seat has a connecting hole penetrating the lower end surface of the top seat. The diameter of the connecting hole is equal to that of the sliding seat; the sliding seat can move up and down along the connecting hole, and the sliding seat has a connecting hole that penetrates through the sliding seat. The upper inlet channel and the upper outlet channel are respectively connected with an upper fluid pipe 105 running through the top seat, and the second boss is located on the lower end surface of the sliding seat.

The outer diameter of the lower plug 102 is equal to the inner diameter of the side wall, the upper end face of the lower plug 102 has a first boss, the lower plug 102 has a lower inlet channel and a lower outlet channel that penetrate the lower plug 102, and the lower inlet channel and The lower outlet passages are respectively connected with a lower fluid pipe 103 penetrating the top seat. Two axial ends of the rubber cylinder 106 are respectively sleeved on the first boss and the second boss.

It should be noted that, in the second connection method, the top seat included in the upper plug 104 and the outer cylinder 101 can be connected by threads, for example, the outer wall of the top seat has an external thread, and the inner wall of the outer cylinder 101 has a connection with the outer cylinder 101. Internal threads that mesh with threads. The connection between the upper plug 104 and the outer cylinder 101 may further include a sealing member to improve the sealing performance of the core holder 1 . The lower plug 102 is in contact with the inner wall of the outer cylinder 101 , and the connection between the lower plug 102 and the outer cylinder 101 is a detachable and movable connection.

In addition, the lower fluid pipe 103 connected to the lower inlet channel and the lower outlet channel may not only penetrate through the top seat, but also penetrate both the top seat and the sliding seat, which is not limited in this embodiment.

In this embodiment, the core holder 1 may also include a second displacement transmitter, and the second displacement transmitter is connected to the sliding seat included in the upper plug 104 to communicate with the sliding seat included in the upper plug 104 . The displacement distance can be accurately measured. In addition, the core holder 1 further includes a temperature measuring probe; the temperature measuring probe is connected to the inner wall of the outer cylinder 101, and the temperature measuring probe is located in the confining pressure cavity, and is used to accurately measure the temperature of the core sample located in the cavity. Measurement.

Further, the core holder 1 may further include a backing ring, the outer diameter of the backing ring is the same as the inner diameter of the rubber cylinder 106, and the backing ring is axially located between the upper plug 104 and the core held by the core holder 1 , the backing ring can be made of metal. Wherein, when the fluid with impurities flows from the upper inlet channel inside the upper plug 104 to the core held by the core holder 1, the impurities in the liquid will accumulate on the surface of the core, and the upper inlet inside the upper plug 104 will be removed. Channel blocked. The function of the backing ring is to separate the upper plug 104 from the core, so as to prevent the upper inlet channel inside the upper plug 104 from being blocked.

In an optional embodiment, the downstream fluid storage tank 6 is connected to the upstream fluid storage tank 3 , so that the fluid in the downstream fluid storage tank 6 and the fluid in the upstream fluid storage tank 3 are both pumped by the upstream pump 5 pressurized fluid, or both are pressurized by the downstream pump 7 . Therefore, when the fluid in the downstream fluid storage tank 6 and the upstream fluid storage tank 3 is the same fluid, only one pump (upstream pump 5 or downstream pump 7) can simultaneously complete the downstream fluid storage tank 6 and the upstream fluid storage tank. The pressurization of the fluid in 3 thus makes the operation easier.

Among them, the downstream fluid storage tank 6 is connected with the upstream fluid storage tank 3 through a pipeline, and there is a valve with a switch function on the pipeline. When the valve is opened, the pipeline is a passage, that is, the downstream fluid storage tank 6 and the upstream fluid storage tank. 3 is connected, at this time, a pump (upstream pump 5 or downstream pump 7) can simultaneously complete the pressurization of the fluid in the downstream fluid storage tank 6 and the upstream fluid storage tank 3; when the valve is closed, the pipeline is open circuit, That is, the downstream fluid storage tank 6 is not in communication with the upstream fluid storage tank 3, then the fluid in the upstream fluid storage tank 3 is pressurized by the upstream pump 5, and the fluid in the downstream fluid storage tank 6 is pressurized by the downstream pump 7, which is suitable for The fluids in the downstream fluid storage tank 6 and the upstream fluid storage tank 3 are implementation environments of different fluids.

Further, in this embodiment, the upstream fluid storage tank 3, the test liquid storage tank 4 and the downstream fluid storage tank 6 are all piston-type containers, and the piston-type container is divided into two cavities by a piston that can be displaced along the container wall. . Taking the upstream fluid storage tank 3 as an example, the use process of the piston container is described. For convenience of description, the cavity communicating with the upstream pump 5 is called the inlet cavity, and the other cavity is called the outlet cavity. When using, on the one hand, the outlet end of the upstream fluid storage tank 3 is closed, and the outlet cavity is filled with the fluid required for the experiment; on the other hand, the upstream pump 5 is turned on to pressurize the clean water to the reference pressure. The fresh water enters the inlet cavity, so that the piston is displaced in the direction of reducing the volume of the outlet cavity, the fluid in the outlet cavity is compressed and the pressure rises, thereby realizing the indirect pressurization of the fluid in the outlet cavity .

When the fluid required for the experiment is a fluid with a high content of suspended solids or is a corrosive fluid, directly pressurizing the fluid required for the experiment by the upstream pump 5 will cause damage to the upstream pump 5, so it is necessary to use a piston type container, the upstream pump 5 only needs to be in direct contact with clean water to complete the indirect pressurization of the fluid in the outlet cavity. Of course, the above-mentioned clean water is only an example. In this embodiment, other cleaning fluids that can directly contact the upstream pump 5 may be used instead of clean water to complete the above-mentioned pressurizing process.

Among them, the upstream fluid storage tank 3 and the test liquid storage tank 4 are selected as ZR-3 type piston containers, with a working pressure of 150MPa and a volume of 2000ml (unit: ml); the downstream fluid storage tank 6 is selected as a ZR-3 type piston type container. , working pressure 150MPa, volume 600ml.

Optionally, there is a pressure guiding pipeline between the upstream pressure transmitter and the downstream pressure transmitter, and there is a differential pressure transmitter on the pressure guiding pipeline, and the differential pressure transmitter is used to indicate the difference between the upstream pressure and the downstream pressure. value. In the actual application process, the upstream pressure measured by the upstream pressure transmitter and the downstream pressure measured by the downstream pressure transmitter are obtained, and the upstream pressure and the downstream pressure are subtracted, and the difference between the upstream pressure and the downstream pressure can also be obtained. The reason for using a differential pressure transmitter is that the differential pressure transmitter has high accuracy and can obtain a more accurate pressure difference.

In addition, the use of differential pressure transmitters can also play a role in the mutual inspection of transmitters. When one transmitter fails, it is convenient to repair and repair each transmitter in time, which ensures the accuracy of the measurement data.

In this embodiment, the differential pressure transmitter is a differential pressure transmitter with a model of DBC-151. The pressure transmitter has a range of 20 MPa, a static pressure bearing capacity of 150 MPa, and an accuracy of 0.25% F·S.

Optionally, the upstream pump 5 is selected as a double plunger non-pulse pump, and the working pressure of the pump is 150MPa, and the flow rate is 10ml/min (ml/min); the downstream pump 7 is selected as an electric metering pump whose model is DJB-80A. It is a single-plunger structure, and the working pressure is greater than 130MPa; the confining pressure pump 8 and the axial pressure pump 10 are all selected as DJB-150A electric pumps. The pump is a single-plunger structure, and the working pressure is greater than 150MPa.

Next, taking the connection of the core holder 1 according to the first connection method as an example, the experimental process of measuring the permeability of shale using the device provided in this embodiment will be described:

First, the simulated pore fluid is loaded into the upstream fluid storage tank 3 and the downstream fluid storage tank 6, and oil is loaded into the confining pressure storage tank 9 to complete the preparation of the experimental liquid; the core sample is loaded into the rubber cylinder 106, and the The rubber tube 106 is sleeved on the boss of the lower plug 102, and the distance between the upper plug 104 and the lower plug 102 is adjusted so that the core sample is in contact with the upper plug 104, and the core sample is completed by the core holder 1. Clamping and fixing;

Next, open the incubator 2, heat the core sample to the reference temperature and maintain the reference temperature; inject gas into the confining pressure storage tank 9 through the gas injection pipeline, so that the oil in the confining pressure storage tank 9 enters the confining pressure cavity, and open the The confining pressure pump 8, after increasing the pressure in the confining pressure cavity (for example, to 6MPa), turns on the upstream pump 5 to pressurize the simulated pore fluid in the upstream fluid storage tank 3 (for example, to 5MPa), and the upstream fluid The simulated pore fluid in the storage tank 3 enters the core sample sequentially through the upper fluid pipe 105 connected to the upper inlet channel and the upper inlet channel inside the upper plug 104, and then sequentially passes through the upper outlet channel inside the upper plug 104 and the upper outlet channel. The upper fluid pipe 105 connected to the channel flows out the core sample; correspondingly, the downstream pump 7 is turned on to pressurize the simulated pore fluid in the downstream fluid storage tank 6 (for example, to 5MPa), and the simulated pore fluid in the downstream fluid storage tank 6 is pressurized. The fluid enters the core sample sequentially through the lower fluid pipe 103 connected to the lower inlet channel and the lower inlet channel inside the lower plug 102, and then flows out through the lower outlet channel inside the lower plug 102 and the lower fluid pipe 103 connected to the lower outlet channel Core samples.

The purpose of heating the core sample by the constant temperature box 2 is to simulate the high temperature environment deep in the formation; the simulated pore fluid pressurized by the upstream pump 5 enters the core sample and discharges the air in the pores of the core sample, so that the upstream end pressure of the core sample is equal to The pressure of the simulated pore fluid is 5MPa; correspondingly, the downstream end pressure of the core sample is also 5MPa, thereby restoring the core sample to the original state in the formation.

It should be noted that the pores inside the core deep in the formation are often filled with fluid (formation water). Although during the sampling process of the core, the extracted core sample will be wax-sealed to prevent air from entering the pores of the core sample. However, during the transfer and use of the core sample, air will inevitably enter the core sample, so it is necessary to use the simulated pore fluid to exhaust the core sample, so that the core sample is as close as possible to the original state where the pores are filled with fluid.

Then, adjust the confining pressure pump 8 to continue to increase the pressure in the confining pressure cavity (for example, to 20MPa); adjust the upstream pump 5 to increase the pressure of the simulated pore fluid in the upstream fluid storage tank 3 (for example, increase to 15MPa), add The pressed simulated pore fluid enters the core sample sequentially through the upper fluid pipe 105 connected to the upper inlet channel and the upper inlet channel inside the upper plug 104, and then passes through the upper outlet channel inside the upper plug 104 and the upper outlet channel connected to the upper outlet channel. The upper fluid pipe 105 flows out of the core sample, and records the indication Pm of the upstream pressure transmitter at this time; close the downstream pump 7 and the valve on the downstream pipeline to seal the downstream end of the core sample, even if the simulated pore fluid no longer passes through the lower plug The lower outlet channel inside the head 102 and the lower fluid pipe 103 connected to the lower outlet channel flow out the core sample, and record the indication Po of the downstream transmitter at this time;

Among them, increasing the pressure of the simulated pore fluid in the upstream fluid storage tank 3 is to simulate the pressure of the drilling fluid column during the drilling process; increasing the pressure in the confining pressure cavity is to ensure that the simulated pore fluid only flows from the axial end face of the core sample. In and out, but not from the radial side wall of the core sample, so the pressure in the confining cavity should be greater than the pressure of the pressurized simulated pore fluid;

After the downstream end of the core sample is closed, the initial pressure of the downstream end of the core sample is Po (that is, 5MPa in the above-mentioned exhausting process), and the pressure of the upstream end of the core sample is always kept at Pm (that is, 15MPa after adjustment by the upstream pump 5). Then the simulated fluid in the pores of the core sample will flow from the upstream end to the downstream end, so that the pressure at the downstream end of the core sample will continue to increase. The permeability of the core samples was calculated.

Finally, when the upstream end pressure measured by the upstream pressure transmitter and the downstream end pressure measured by the downstream pressure transmitter are balanced (for example, the difference between the upstream end pressure and the downstream end pressure is less than 5% as a balance), close the The upstream pump 5 and the confining pressure pump 8 complete the acquisition of experimental data, and calculate the acquired experimental data according to the following formula to obtain the permeability of the core sample:

In the formula: K—permeability, unit: L/m3 (liter/cubic meter);

μ—drilling fluid viscosity, unit: mm2/s (square millimeter/s);

β——static compressibility of fluid, unit: % (percentage);

V——The downstream closed volume, unit: m ³ (cubic meter);

L—length of rock sample, unit: m (meter);

A—cross-sectional area of rock sample, unit: m ² (square meter);

Pm—pressure at the upstream end of the core sample, unit: MPa;

Po—the initial pressure at the downstream end of the core sample, unit: MPa;

P _t2 —pressure at the downstream end of the core sample at time t ₂ , unit: MPa;

P _t1 —pressure at the downstream end of the core sample at time _t1 , unit: MPa.

In addition to measuring the permeability of shale, the device provided in this embodiment can also measure the membrane efficiency of shale. The experimental process is as follows:

First, load the low activity solution into the test liquid storage tank 4, load the simulated pore fluid into the upstream fluid storage tank 3 and the downstream fluid storage tank 6, and load the oil into the confining pressure storage tank 9 to complete the experimental liquid The preparation; put the core sample into the rubber cylinder 106, set the rubber cylinder 106 on the boss of the lower plug 102, place a reference thickness of the gasket on the end face of the core sample close to the end of the upper plug 104, adjust the upper The distance between the plug 104 and the lower plug 102 is such that the backing ring is in contact with the upper plug 104 to complete the clamping and fixing of the core sample by the core holder 1;

It should be noted that the above-mentioned low-activity solution can be a mud filtrate that simulates drilling fluid, and the process of contacting the low-activity solution with the core sample is the simulation process of the drilling fluid column scouring the mud shale borehole wall during the drilling process. During the process, the mud filtrate continuously scours the core sample, and a mud cake of a certain thickness is formed on the end face of the core sample. Therefore, it is necessary to place a reference thickness of the gasket on the end face of the core sample to prevent the mud cake from blocking the upper inlet channel and the inside of the upper plug 104. On the exit channel, it will affect the normal progress of the experiment.

Next, open the incubator 2 to heat the core samples to the reference temperature and maintain the reference temperature; open the confining pressure pump 8 to increase the pressure in the confining pressure cavity, and open the upstream pump 5 to perform the simulation on the simulated pore fluid in the upstream fluid storage tank 3. Pressurize, increase the pressure at the upstream end of the core sample, turn on the downstream pump 7 to increase the pressure at the downstream end of the core sample, and make the pressure at the upstream and downstream ends of the core sample equal (for example, make the pressure at the upstream and downstream ends 5MPa), record the upstream and downstream pressure at this time Transmitter indication Ps. This process is the same as that of the experiment to measure the permeability of shale, so it will not be repeated here.

Then, the simulated pore fluid entering the upper plug 104 is replaced with a low activity solution, and the pressure at the upstream and downstream ends of the core sample is kept unchanged during the replacement process; after the replacement, the downstream pump 7 and the valve on the downstream pipeline are closed. , so that the downstream end of the core sample is closed.

After the downstream end of the core sample is closed, the initial pressures at the upstream and downstream ends of the core sample are both Ps, wherein the fluid in the internal pores of the upstream end of the core sample is a low activity solution, while the fluid in the internal pores of the downstream end of the core sample is a low activity solution. It is a simulated pore fluid whose activity is higher than that of the low-activity solution. Therefore, under the action of the poor activity, the water molecules in the simulated pore fluid will transfer to the low-activity solution, so that the pressure at the downstream end of the core sample gradually decreases. The downstream pressure transmitter measures the downstream pressure of the core sample at different times in the process, and the pressure difference between the upstream and downstream ends of the process is measured by the differential pressure transmitter, which is used to calculate the membrane efficiency of the core sample.

Finally, when the upstream pressure measured by the upstream pressure transmitter and the downstream pressure measured by the downstream pressure transmitter are balanced (for example, the difference between the upstream pressure and the downstream pressure is less than 5% as a balance) , close the upstream pump 5 and the confining pressure pump 8, complete the acquisition of experimental data, and calculate the acquired experimental data according to the following formula to obtain the membrane efficiency of the core sample:

In the formula, σ—membrane efficiency;

ΔPnd—the maximum pressure difference between the upstream end and the downstream end of the core sample measured by the differential pressure transmitter during the experiment, unit: MPa;

Pn theory—theoretically the maximum pressure difference between the upstream end and the downstream end of the core sample, unit: MPa;

It should be noted that the essence of the experiment to measure the permeability of mud shale is to measure no chemical potential difference (the fluids in the internal pores of the upstream and downstream ends are simulated pore fluids, so there is no chemical potential difference), only hydraulic pressure. When the difference is applied, the flow law of the fluid in the core sample; correspondingly, for the experiment to measure the efficiency of the shale film, the essence is to measure the effect of no hydraulic pressure difference (the fluid pressure in the internal pores of the upstream and downstream ends is the same, so there is no When only the chemical potential difference acts, the flow law of the fluid in the core sample. On the whole, the above two experiments have studied the shale reservoir from the perspectives of mechanics and chemistry, and the shale permeability and membrane efficiency obtained from the experiments can be further used to establish a mechanical-chemical coupled analysis model. In order to make a more realistic evaluation of the stability of shale wellbore.

In addition, it should be noted that the core samples used in the above two experimental processes are all natural core samples, and the experimental device provided in this embodiment can also use artificial core samples to measure shale permeability and membrane efficiency. Among them, in order to ensure that the strength of the artificial core sample is close to that of the natural core sample, the artificial core sample needs to be compacted before using the artificial core sample for the experiment. The specific process is as follows:

The same as the above experimental process, the artificial core sample to be compacted is clamped and fixed by the core holder 1; the confining pressure pump 8 is opened, the pressure in the confining pressure cavity is increased (for example, increased to 20MPa), and the axial pressure pump 10 is opened. , the pressure in the axial pressure cavity is increased (for example, to 20MPa), the sliding seat included in the lower plug 102 is displaced in the direction close to the upper plug 104 by the pressure in the axial pressure cavity, thereby making the artificial core sample It is compacted by the pressing force between the upper plug 104 and the lower plug 102 .

During the process of the artificial core sample being compacted, its strength gradually increases, and the compressibility in the axial direction also decreases accordingly. The amount of displacement in the direction approaching the upper plug 104 decreases over time. The displacement distance of the sliding seat included in the lower plug 102 can be measured by the displacement transmitter in the axial pressure cavity, and the displacement of the sliding seat included in the lower plug 102 is less than 10 μm/h (unit: μm/hour), It can be considered that the artificial core sample has been compacted, and the compacted artificial core sample can be used in the above experiments of measuring the permeability of shale and measuring the efficiency of shale membrane.

To sum up, the core holder provided by the embodiment of the present invention has an upper inlet end, an upper outlet end, a lower inlet end and a lower outlet end, and the upper inlet end and the upper outlet end conduct liquid circulation at the upstream end of the core, and through the upper inlet end and the upper outlet end The lower inlet end and the lower outlet end carry out liquid circulation at the downstream end of the core. Since the liquid circulation at the upstream and downstream ends of the core is independent and does not interfere with each other, the accuracy of shale parameter measurement is improved.

Further, in the embodiment of the present invention, the upper plug is separated from the core by a backing ring, so that a certain distance is formed between the upper plug and the core, then when measuring the parameters of shale, the upstream end of the core can be circulated containing Impurities in the liquid, the impurities in the liquid can be accumulated between the upper plug and the core, so as to avoid blocking the upper inlet channel and the upper outlet channel in the upper plug, thus expanding the applicable scope of the device.

All the above-mentioned optional technical solutions can be combined arbitrarily to form optional embodiments of the present disclosure, which will not be repeated here.

The above descriptions are only the embodiments of the present invention and are not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention. Inside.

Claims (10)

1. A shale parameter measuring device, characterized in that the device comprises: a core holder (1), a constant temperature box (2), an upstream fluid storage tank (3), a test fluid storage tank (4), upstream pump (5), downstream fluid storage tank (6), downstream pump (7), confining pressure pump (8), confining pressure storage tank (9) and axial pressure pump (10); Wherein, the core holder (1) is located in the incubator (2), the inlet end of the upstream fluid storage tank (3), the inlet end of the test fluid storage tank (4) and the upstream The outlet end of the pump (5) is connected through an inlet three-way valve, and the outlet end of the upstream fluid storage tank (3), the outlet end of the test fluid storage tank (4) and the outlet end of the core holder (1) are connected. The upper inlet end is connected by an outlet three-way valve, and there is an upstream pressure transmitter between the outlet three-way valve and the upper inlet end of the core holder (1), and the core holder (1) has an upstream pressure transmitter. The upper outlet end communicates with the outside of the incubator (2); the inlet end of the downstream fluid storage tank (6) is connected to the outlet end of the downstream pump (7), and the outlet of the downstream fluid storage tank (6) The end is connected to the lower inlet end of the core holder (1), and there is a downstream pressure transmitter between the downstream fluid storage tank (6) and the lower inlet end of the core holder (1), The lower outlet end of the core holder (1) communicates with the outside of the incubator (2); The confining pressure pump (8) and the confining pressure storage tank (9) are all communicated with the confining pressure cavity inside the core holder (1), and the confining pressure pump (8) is connected to the confining pressure cavity. A confining pressure transmitter is arranged between the cavities; the outlet end of the axial pressure pump (10) is communicated with the axial pressure cavity inside the core holder (1), and the axial pressure pump (10) is connected to An axial pressure transmitter is arranged between the axial pressure cavities; The core holder (1) comprises an outer cylinder (101), a lower plug (102), a lower fluid pipe (103), an upper plug (104), an upper fluid pipe (105) and a rubber cylinder (106); The lower plug (102) and the upper plug (104) are both connected to the outer cylinder (101), the lower fluid pipe (103) is connected to the lower plug (102), and the upper The fluid pipe (105) is connected with the upper plug (104), and the rubber cylinder (106) is axially located between the lower plug (102) and the upper plug (104). 2. The device according to claim 1, characterized in that, the outer cylinder (101) comprises a top cover and a side wall, and the lower plug (102) sequentially comprises a base, a sliding seat, and a connecting base from bottom to top. Two bosses, the side wall is connected to the base, the inner wall of the side wall, the upper end surface of the base, the outer wall of the sliding seat, the outer wall of the rubber cylinder (106) and the upper plug The lower end face of (104) encloses the confining pressure cavity; The interior of the base is the axial pressure cavity, the base is provided with a connection hole penetrating the upper end surface of the base, and the diameter of the connection hole is equal to the outer diameter of the sliding seat; The sliding seat can move up and down along the connecting hole, and the sliding seat has a lower inlet channel and a lower outlet channel passing through the sliding seat. The lower fluid pipes (103) are connected to each other, and the second boss is located on the upper end face of the sliding seat; The outer diameter of the upper plug (104) is equal to the inner diameter of the side wall, the lower end surface of the upper plug (104) is provided with a first boss, and the upper an upper inlet channel and an upper outlet channel of the plug (104), the upper inlet channel and the upper outlet channel are respectively connected with an upper fluid pipe (105) passing through the base; The two axial ends of the rubber cylinder (106) are respectively sleeved on the first boss and the second boss. 3. The shale parameter measuring device according to claim 2, wherein the core holder (1) further comprises: a first displacement transmitter; The first displacement transmitter is connected with the sliding seat. 4. The mud shale parameter measuring device according to claim 1, wherein the outer cylinder (101) comprises a bottom cover and a side wall, and the upper plug (104) sequentially comprises connected A top seat, a sliding seat and a second boss, the side wall is connected to the top seat, the inner wall of the side wall, the lower end surface of the top seat, the outer wall of the sliding seat, the rubber cylinder (106 ) and the upper end face of the lower plug (102) to enclose the confining pressure cavity; The inside of the top seat is the axial pressure cavity, the top seat is provided with a connecting hole penetrating the lower end surface of the top seat, and the diameter of the connecting hole is equal to the diameter of the sliding seat; The sliding seat can move up and down along the connecting hole, and the sliding seat has an upper inlet channel and an upper outlet channel passing through the sliding seat. The upper fluid pipes (105) of the seat are connected, and the second boss is located on the lower end surface of the sliding seat; The outer diameter of the lower plug (102) is equal to the inner diameter of the side wall, the upper end surface of the lower plug (102) is provided with a first boss, and the lower plug (102) has a penetrating portion through the lower plug (102). a lower inlet channel and a lower outlet channel of the plug (102), the lower inlet channel and the lower outlet channel are respectively connected with a lower fluid pipe (103) passing through the top seat; The two axial ends of the rubber cylinder (106) are respectively sleeved on the first boss and the second boss. 5. The shale parameter measuring device according to claim 4, wherein the core holder (1) further comprises: a second displacement transmitter; The second displacement transmitter is connected with the sliding seat. 6. The shale parameter measuring device according to any one of claims 1-5, wherein the core holder (1) further comprises: a backing ring; The outer diameter of the backing ring is the same as the inner diameter of the rubber cylinder (106), and the backing ring is axially located between the upper plug (104) and the core held by the core holder (1). . 7. The shale parameter measuring device according to any one of claims 1-5, wherein the core holder (1) further comprises: a temperature measuring probe; The temperature measuring probe is connected to the inner wall of the outer cylinder (101), and the temperature measuring probe is located in the confining pressure cavity. 8. The shale parameter measurement device according to any one of claims 1-5, wherein the downstream fluid storage tank (6) is connected to the upstream fluid storage tank (3). 9. The shale parameter measurement device according to any one of claims 1-5, wherein a pressure guiding pipeline is arranged between the upstream pressure transmitter and the downstream pressure transmitter, and the There is a differential pressure transmitter on the pressure line. 10. The shale parameter measurement device according to any one of claims 1-5, wherein the upstream fluid storage tank (3), the test fluid storage tank (4) and the downstream fluid storage tank (6) All are piston containers.

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