Testing Device and Method for the Action of Stress-Drilling Fluid Flow-Hydration on Formation

Abstract

The present invention discloses a testing device and method for the action of stress - drilling fluid flow - hydration on a formation, which includes a pressure autoclave and a central control servo, as well as a drilling fluid control system, a temperature control system, a circulation control system, a hydraulic system, and a deformation monitoring system that are respectively connected to the pressure autoclave and the central control servo at both ends. The drilling fluid control system is connected to the pressure autoclave through a pressure sensor and a drilling fluid injection and vent pipeline. The temperature control system is connected to the pressure autoclave through a temperature sensor and an electromagnetic heating device. The circulation control system is connected to the pressure autoclave through a circulation agitator. Different stresses are applied to a rock sample by the pressure conversion head in the pressure autoclave, and it acts with a high - temperature and high - pressure circulating drilling fluid, and then the rock sample is taken out and various parameters are measured. The comprehensive research on the influence of the formation stress state, the temperature, pressure, flow rate of the drilling fluid, and the hydration action on the formation properties is realized, which has the advantages of high efficiency and high precision.

Description

Technical Field

[0001] The present invention belongs to the field of oil and gas drilling engineering, and specifically relates to a test device and method for the action of stress - drilling fluid flow - hydration on a formation. Background Art

[0002] During the drilling process of an oil and gas reservoir, due to the differences in physical and chemical properties between the formation pore fluid in the pores of the rock near the wellbore and the drilling fluid circulating in the wellbore, changes in pore fluid pressure, density, ion composition, and capillary force will occur. At the same time, the temperature and pressure of the drilling fluid increase with the increase of the wellbore depth, further affecting the physical and chemical properties of the drilling fluid. Under such complex influences, various properties of the wellbore rock, including mechanical properties, will change. CN20170010420 discloses a simulation experimental device and method for the interaction between mudstone and drilling fluid under formation conditions. Although it can simulate the interaction between the drilling fluid and the rock sample under high - temperature and high - pressure formation conditions, it does not consider the influence of the stress state of the rock sample itself on the properties of the rock sample after interaction with the drilling fluid. In fact, for formation rocks in different geological environments, their in - situ stress states are different, and the stress states of the wellbore rock after drilling the wellbore may vary greatly. At this time, the stress state of the rock itself is an important factor affecting the properties of the wellbore rock by the circulating drilling fluid in the wellbore. Accurately obtaining the influence law of the drilling fluid on the properties of the wellbore rock under different stress conditions is of crucial guiding significance for wellbore stability analysis and drilling fluid performance evaluation during the drilling process, and also lays a foundation for the design and optimization of the efficient drilling and completion plan for oil and gas wells. The present invention proposes a test device and method for the action of stress - drilling fluid flow - hydration on a formation to accurately obtain the influence law of the drilling fluid on the properties of the wellbore rock under different stress conditions and realize the effective and accurate research of formation parameters. Summary of the Invention

[0003] In order to solve the above - mentioned technical problems, the present invention proposes a test device and method for the action of stress - drilling fluid flow - hydration on a formation, which realizes the comprehensive research on the influence of formation stress state, temperature, pressure, flow rate of the drilling fluid, and hydration on formation properties, and has the advantages of high efficiency and high precision.

[0004] A test device for the action of stress - drilling fluid flow - hydration on a formation, the test device includes a pressure kettle, a central control servo, a drilling fluid control system, a temperature control system, a circulation control system, a hydraulic system, and a deformation monitoring system,

[0005] The drilling fluid control system, the temperature control system, the circulation control system, the hydraulic system, and the deformation monitoring system are respectively connected to the central control servo;

[0006] The drilling fluid control system is connected to the autoclave through a pressure sensor and a drilling fluid injection and venting pipeline. The pressure sensor is arranged on the autoclave and extends into the interior of the autoclave. The drilling fluid control system collects the fracturing fluid pressure data of the pressure sensor for the central control servo, and according to the instructions of the central control servo, completes the vacuum pumping in the autoclave and the injection, pressurization and backflow of the drilling fluid through the drilling fluid injection and venting pipeline;

[0007] The exterior of the autoclave body is covered with an electromagnetic heating device, and a temperature sensor is integrated at the bottom of the autoclave. The temperature control system is respectively connected to the temperature sensor and the electromagnetic heating device;

[0008] A circulation agitator is arranged at the bottom of the autoclave and extends into the interior of the autoclave. The circulation control system is connected to the autoclave through the circulation agitator;

[0009] The hydraulic system is connected to the hydraulic chamber of the autoclave through a hydraulic pipeline;

[0010] The interior of the autoclave is filled with drilling fluid, and the test rock samples are placed in the autoclave. High-precision strain gauges are respectively arranged axially and radially on each test rock sample. The deformation monitoring system is connected to the test rock samples in the autoclave through the high-precision strain gauges and data transmission cables;

[0011] The autoclave converts the hydraulic pressure in the hydraulic chamber at the top of the autoclave into different axial pressures applied to each test rock sample in the autoclave, acts with the high-temperature and high-pressure circulating drilling fluid, and measures the required rock sample parameters.

[0012] Furthermore, the autoclave is made of an alloy material that is resistant to high temperature, high pressure and corrosion, and includes a detachable sealed top cover, a highly heat-conductive autoclave body, a fixed sealed bottom cover and a pressure conversion ram. The detachable sealed top cover is arranged on the top of the highly heat-conductive autoclave body and is connected by fastening bolts. A hollow hydraulic chamber is formed inside the detachable sealed top cover. A number of identical stepped ram grooves are equidistantly distributed on the lower cavity wall of the hydraulic chamber. The stepped ram grooves communicate the lower cavity wall of the hydraulic chamber with the lower surface of the detachable sealed top cover. The pressure conversion ram is arranged in the stepped ram grooves.

[0013] Furthermore, the fixed sealed bottom cover is integrally installed with a temperature sensor, a pressure sensor, a circulation agitator, a drilling fluid injection and venting pipeline, and a data transmission cable; and a number of grooves with the same radial dimension for fixing rock samples are distributed on the inner surface of the fixed sealed bottom cover;

[0014] One end of the pressure conversion indenter has the same radial dimension as a certain step in the stepped indenter groove of the detachable sealing top cover, and the other end has the same radial dimension as the inner surface groove of the fixed sealing bottom cover. A sealing ring is provided at the contact between the side surface of the pressure conversion indenter and the stepped indenter groove, and each pressure conversion indenter is pre-assembled in the stepped indenter groove.

[0015] Furthermore, the number of the stepped indenter grooves, the inner surface grooves of the fixed sealing bottom cover, and the pressure conversion indenters is equal; the radial dimension of the inner surface groove of the fixed sealing bottom cover is the same as the size of the test rock sample.

[0016] A test method for a test device that uses stress - drilling fluid flow - hydration to act on a formation, the test method includes the following steps:

[0017] Step 1: Remove the detachable sealing top cover, place a number of test rock samples into the autoclave, and place the bottom of each test rock sample in the inner surface groove of the fixed sealing bottom cover. High-precision strain gauges are respectively arranged axially and radially on each test rock sample. Then, accurately place the assembly of the pressure conversion indenter and the detachable sealing top cover on the top of the test rock sample, and install and fasten the detachable sealing top cover.

[0018] Step 2: Start the hydraulic system, inject hydraulic oil into the hydraulic chamber through the hydraulic pipeline until the specified hydraulic value is reached in the hydraulic chamber. Use the drilling fluid control system and the drilling fluid injection and vent pipeline to evacuate the inside of the autoclave, and then inject drilling fluid into the autoclave through the drilling fluid injection and vent pipeline and pressurize it. During the pressurization process, the drilling fluid control system monitors the pressure inside the autoclave in real time through the pressure sensor until the pressurization stops after reaching the specified pressure. Use the temperature control system to turn on the electromagnetic heating device and obtain the data of the temperature sensor, heat the drilling fluid to the specified temperature, and use the circulation control system to turn on the circulation agitator to make the drilling fluid circulate and flow in the autoclave at a specified speed.

[0019] Step 3: After the drilling fluid acts on the test rock sample for a certain period of time, record the axial and radial strain data of each test rock sample under different stress conditions collected by the central control servo. Then, turn off each system, backflow the fracturing fluid, open the detachable sealing top cover, take out the test rock sample, and measure and calculate various required property parameters.

[0020] Beneficial effects: The beneficial effects of the present invention are as follows:

[0021] 1) Under the same drilling fluid environmental conditions, by using the pressure conversion indenter, the hydraulic pressure in the hydraulic chamber of the detachable sealing top cover of the autoclave by the triaxial mechanical testing machine is converted into different magnitudes of axial pressure applied to each test rock sample in the autoclave, controlling a single variable, and improving the research accuracy and research efficiency.

[0022] 2) It can simulate the high-temperature and high-pressure conditions in the wellbore and the circulating flow of drilling fluid during the actual drilling construction process, and can obtain research results that conform to the actual engineering situation.

[0023] 3) The autoclave has a simple and reliable structure, and the overall experimental device realizes informatization and modular control, making the device operation more standardized. Description of the Drawings

[0024] Figure 1 Schematic diagram of the simulation research device described in the present invention;

[0025] Figure 2 For the present invention Figure 1 Schematic diagram of the internal structure after longitudinal section expansion of the autoclave within the dashed box;

[0026] Figure 3 For Figure 2 Profile top view of the AA′ section;

[0027] Figure 4 Top view of the inner surface of the fixed sealing bottom cover described in the present invention;

[0028] Figure 5 Schematic diagram of the pressure conversion ram described in the present invention;

[0029] Figure 6 Cross-sectional view of the ribbed plate type circulation agitator described in the present invention. Detailed Embodiment

[0030] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments.

[0031] Such as Figure 1As shown in the figure, it is a schematic diagram of a test device for the action of stress - drilling fluid flow - hydration on the formation according to the present invention, including a pressure kettle 1, a central control servo 4, a drilling fluid control system 3, a temperature control system 2, a circulation control system 5, a hydraulic system 6 and a deformation monitoring system. The drilling fluid control system 3, the temperature control system 2, the circulation control system 5, the hydraulic system 6 and the deformation monitoring system are respectively connected to the central control servo 4. The drilling fluid control system 3 is connected to the pressure kettle 1 through a pressure sensor 1 - 6 and a drilling fluid injection and vent pipeline 7. The temperature control system 2 is connected to the pressure kettle 1 through a temperature sensor 1 - 5 and an electromagnetic heating device 1 - 8. The circulation control system 5 is connected to the pressure kettle 1 through a rib - plate type circulation agitator 1 - 7. The hydraulic system 6 is connected to the pressure kettle 1 through a hydraulic cavity 1 - 10 and a hydraulic pipeline 11. The deformation monitoring system is connected to a test rock sample 9 in the pressure kettle 1 through a high - precision strain gauge 12 and a data transmission cable 8.

[0032] As Figure 2 shown, it is a schematic diagram of the internal structure after the longitudinal section of the pressure kettle of the present invention is unfolded. The pressure kettle 1 is made of an alloy material with high temperature resistance, high pressure resistance and corrosion resistance, and includes a circular detachable sealed top cover 1 - 1, a high - heat - conduction cylindrical kettle body 1 - 2, a circular fixed sealed bottom cover 1 - 3 and a pressure conversion ram 1 - 4. The detachable sealed top cover 1 - 1 and the circular fixed sealed bottom cover 1 - 3 are bolt - connected to the high - heat - conduction cylindrical kettle body 1 - 2. Figure 3 , Figure 4 , Figure 5 are respectively Figure 2Profile top view of the AA' section, top view of the inner surface of the fixed sealing bottom cover 1-3, and schematic diagram of the pressure conversion ram 1-4. A hollow hydraulic cavity 1-10 is formed inside the detachable sealing top cover 1-1, and the hydraulic pipeline is connected to the hydraulic cavity 1-10 through the hydraulic pipeline installation hole 1-1-2. Four identical stepped ram grooves 1-1-1 are equidistantly distributed on the lower cavity wall of the hydraulic cavity 1-10. The diameters of each step of the stepped ram groove 1-1-1 are Φ1 = 50mm, Φ2 = 45mm, Φ3 = 40mm, and Φ4 = 35mm respectively. The stepped ram groove 1-1-1 connects the lower cavity wall of the hydraulic cavity 1-10 with the lower surface of the detachable sealing top cover 1-1. The inner cavity size of the autoclave 1 is Φ = 150×50mm. The fixed sealing bottom cover 1-3 is integrally installed with a temperature sensor 1-5, a pressure sensor 1-6, a ribbed plate type circulation agitator 1-7, a drilling fluid injection and vent pipeline 7, and a data transmission cable 8. And its inner surface is distributed with 4 inner surface grooves 1-3-1 of the same diameter Φ0 = 25mm and a depth of 3mm. The fixed sealing bottom cover 1-3 is also provided with a pressure sensor installation hole 1-3-2, a ribbed plate type circulation agitator installation hole 1-3-3, a temperature sensor installation hole 1-3-4, a drilling fluid injection and vent pipeline installation hole 1-3-5, a sealing ring 1-3-6, and a bolt connection hole 1-3-7.

[0033] The high thermal conductivity cylindrical kettle body 1-2 is covered with the electromagnetic heating device 1-8. One end of the pressure conversion ram 1-4 has the same radial dimension as a certain step in the stepped ram groove 1-1-1 of the detachable sealing top cover 1-1, and the other end has the same radial dimension as the inner surface groove 1-3-1 of the fixed sealing bottom cover 1-3. Sealing rings 1-9 are provided at the contact positions of the two ends of the pressure conversion ram 1-4 with the stepped ram groove 1-1-1. Each pressure conversion ram 1-4 is pre-assembled in the stepped ram groove 1-1-1 to play a role of sealing and isolation between the hydraulic cavity 1-10 and the drilling fluid cavity.

[0034] The number of the stepped ram grooves 1-1-1 of the detachable sealing top cover 1-1, the inner surface grooves 1-3-1 of the fixed sealing bottom cover 1-3, and the pressure conversion rams 1-4 is 4. The diameter of the inner surface groove 1-3-1 of the fixed sealing bottom cover 1-3 is the same as that of the test rock sample 9, and the test rock sample 9 selects 4 standard size (25×50mm) rock samples with the same physical property parameters.

[0035] The drilling fluid control system 3 collects the fracturing fluid pressure data P of the pressure sensors 1-6 for the central control servo 4, and according to the instructions of the central control servo 4, evacuates the pressure kettle 1 and injects, pressurizes and discharges the drilling fluid 10 through the drilling fluid injection and vent pipeline 7.

[0036] The temperature control system 2 collects the data T of the temperature sensors 1-5 for the central control servo 4, and directly controls the electromagnetic heating devices 1-8 according to the instructions of the central control servo 4.

[0037] The circulation control system 5 directly controls the ribbed circulation agitator 1-7 according to the instructions of the central control servo 4 to realize the circulation of the drilling fluid 10 in the pressure kettle 1. Figure 6 It is a cross-sectional view of the ribbed circulation agitator 1-7 of the present invention.

[0038] Use Figure 1 The experimental method for the combined action of stress - drilling fluid flow - hydration on the formation using the experimental device shown. The method specifically includes the following steps:

[0039] (1) Remove the detachable sealing top cover 1-1, place 4 test rock samples 9 into the pressure kettle 1, with the bottom of each test rock sample 9 placed in the inner surface groove 1-3-1 of the fixed sealing bottom cover 1-3. High-precision strain gauges 12 are respectively arranged axially and radially on each test rock sample 9. Then accurately place the assembly of the pressure conversion head 1-4 and the detachable sealing top cover 1-1 on the top of the test rock sample 9, and install and fasten the detachable sealing top cover 1-1 using the fastening bolts 13;

[0040] (2) Turn on the hydraulic system 6 until the specified hydraulic pressure P L = 35 MPa in the hydraulic cavity 1-10 is reached. Different pressure conversion heads 1-4 convert the hydraulic pressure into different axial pressures on the test rock samples 9. Use the drilling fluid control system 3 and the drilling fluid injection and vent pipeline 7 to evacuate the inside of the sealed pressure kettle 1, and then inject the drilling fluid 10 into the pressure kettle 1 and pressurize it to the specified pressure P W = 25 MPa. Use the temperature control system 2 to turn on the electromagnetic heating devices 1-8 and obtain the data of the temperature sensors 1-5, and heat the drilling fluid 10 to the specified temperature T W = 80 °C. Use the circulation control system 5 to turn on the ribbed circulation agitator 1-7 and adjust the rotation speed to 200 revolutions per minute to make the drilling fluid 10 circulate in the pressure kettle 1;

[0041] After the drilling fluid 10 acts on the test rock sample 9 for a certain period of time, record the axial and radial strain data of each test rock sample 9 under different stress conditions collected by the central control servo 4. Then, shut down each system, flow back the fracturing fluid 10, open the detachable sealing top cover 1-1 to take out the test rock sample 9 and measure and calculate various required property parameters. The present invention realizes the experimental study on the combined action of stress - drilling fluid flow - hydration on the formation under the wellbore environment of high temperature and high pressure. On the premise of simulating the temperature, pressure and drilling fluid circulation conditions of the actual formation drilling working condition, the pressure conversion head 1-4 is used to apply different simulated in-situ stresses to the test rock sample 9, which has high research accuracy and research efficiency.

[0042] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by those skilled in the art within the scope of the essence of the present invention should also fall within the protection scope of the present invention.

Claims

1. A test device for the action of stress - drilling fluid flow - hydration on a formation, characterized in that, The test device includes an autoclave, a central control servo, a drilling fluid control system, a temperature control system, a circulation control system, a hydraulic system, and a deformation monitoring system. The drilling fluid control system, the temperature control system, the circulation control system, the hydraulic system, and the deformation monitoring system are respectively connected to the central control servo. The drilling fluid control system is connected to the autoclave through a pressure sensor and a drilling fluid injection and venting pipeline. The pressure sensor is arranged on the autoclave and extends into the interior of the autoclave. The drilling fluid control system collects the fracturing fluid pressure data of the pressure sensor for the central control servo, and according to the instructions of the central control servo, completes the vacuum pumping, drilling fluid injection, pressurization, and backflow in the autoclave through the drilling fluid injection and venting pipeline. An electromagnetic heating device is covered outside the autoclave body, and a temperature sensor is integrated at the bottom of the autoclave. The temperature control system is respectively connected to the temperature sensor and the electromagnetic heating device. A circulation agitator is arranged at the bottom of the autoclave and extends into the interior of the autoclave. The circulation control system is connected to the autoclave through a ribbed circulation agitator; the ribbed circulation agitator is started by the circulation control system and the rotation speed is adjusted to 200 revolutions per minute. The hydraulic system is connected to the hydraulic chamber of the autoclave through a hydraulic pipeline. The interior of the autoclave is filled with drilling fluid, and the test rock samples are placed in the autoclave. High-precision strain gauges are respectively arranged axially and radially on each test rock sample. The deformation monitoring system is connected to the test rock samples in the autoclave through the high-precision strain gauges and data transmission cables. The autoclave converts the hydraulic pressure in the hydraulic chamber at the top of the autoclave into different magnitudes of axial pressure applied to each test rock sample in the autoclave, acts with the high-temperature and high-pressure circulating drilling fluid, and measures the required rock sample parameters. The autoclave is made of an alloy material with high temperature resistance, high pressure resistance, and corrosion resistance, and includes a detachable sealed top cover, a high thermal conductivity autoclave body, a fixed sealed bottom cover, and a pressure conversion ram. The detachable sealed top cover is arranged on the top of the high thermal conductivity autoclave body and is connected by fastening bolts. A hollow hydraulic chamber is formed inside the detachable sealed top cover. A number of identical stepped ram grooves are equidistantly distributed on the lower chamber wall of the hydraulic chamber. The stepped ram grooves communicate the lower chamber wall of the hydraulic chamber with the lower surface of the detachable sealed top cover. The pressure conversion ram is arranged in the stepped ram grooves. The fixed sealed bottom cover is integrally installed with a temperature sensor, a pressure sensor, a circulation agitator, a drilling fluid injection and venting pipeline, and a data transmission cable; and a number of grooves for fixing rock samples with the same radial dimension are distributed on the inner surface of the fixed sealed bottom cover. One end of the pressure conversion ram has the same radial dimension as a certain step in the stepped ram groove of the detachable sealed top cover, and the other end has the same radial dimension as the groove on the inner surface of the fixed sealed bottom cover. A sealing ring is arranged at the contact between the side surface of the pressure conversion ram and the stepped ram groove. Each pressure conversion ram is pre-assembled in the stepped ram groove. The number of the stepped indenter grooves, the inner surface grooves of the fixed sealing bottom cover, and the pressure conversion indenter are equal; the radial dimension of the inner surface grooves of the fixed sealing bottom cover is the same as the size of the test rock sample.

2. A testing method using the testing device for the effect of stress-drilling fluid flow-hydration on formation described in claim 1, characterized in that, The test method includes the following steps: Step 1: Remove the detachable sealing top cover, place a number of test rock samples into the autoclave, place the bottom of each test rock sample in the inner surface groove of the fixed sealing bottom cover, respectively set high-precision strain gauges axially and radially on each test rock sample, then accurately place the assembly of the pressure conversion indenter and the detachable sealing top cover on the top of the test rock sample, and install and fasten the detachable sealing top cover. Step 2: Turn on the hydraulic system, inject hydraulic oil into the hydraulic chamber through the hydraulic pipeline until the specified hydraulic value is reached in the hydraulic chamber, use the drilling fluid control system and the drilling fluid injection and vent pipeline to evacuate the inside of the autoclave, then inject drilling fluid into the autoclave through the drilling fluid injection and vent pipeline and pressurize. During the pressurization process, the drilling fluid control system monitors the pressure inside the autoclave in real time through the pressure sensor until the pressurization stops after reaching the specified pressure. Use the temperature control system to turn on the electromagnetic heating device and obtain the data of the temperature sensor, heat the drilling fluid to the specified temperature, and use the circulation control system to turn on the circulation agitator to make the drilling fluid circulate in the autoclave at a specified speed. Step 3: After the drilling fluid acts on the test rock sample for a certain period of time, record the axial and radial strain data of each test rock sample under different stress conditions collected by the central control servo, then turn off each system, backflow the fracturing fluid, open the detachable sealing top cover, take out the test rock sample, and measure and calculate various required property parameters.

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