A compact core matrix imbibition capacity evaluation experimental device and method

Abstract

The application discloses a kind of compact core matrix imbibition capacity evaluation experimental device and method, the evaluation experimental device includes first container, second container, communication pipe, core holder, injection pump, back pressure valve and confining pressure pump;Core holder and communication pipe are both arranged between first container and second container;Confining pressure pump is connected to core holder by first pipeline, injection pump is connected to first container by second pipeline, back pressure valve is connected to second container by third pipeline;The top of first container is provided with first volumetric metering device, and the top of second container is provided with second volumetric metering device;Valve is arranged on first pipeline, second pipeline, third pipeline and communication pipe;Pressure gauge is arranged on first pipeline, second pipeline, third pipeline. By the device and method of the application, the imbibition capacity and imbibition contribution size (imbibition contribution ratio) of compact core matrix can be effectively evaluated, thereby providing basic research for effective development of oil well.

Description

Technical Field

[0001] This invention relates to the field of petroleum development technology, specifically to an experimental apparatus and method for evaluating the permeability and absorption capacity of a dense core matrix. Background Technology

[0002] Shale oil has low matrix permeability, typically requiring fracturing to increase well control range. Some researchers believe that crude oil flows from the tight core matrix into fractures primarily through two pathways: seepage and adsorption. The contribution of tight matrix adsorption significantly influences production policies for some oil wells. Currently, some core adsorption experiments have been conducted. However, research on how to effectively evaluate the contribution of adsorption is relatively limited, yet assessing the contribution of tight matrix adsorption is crucial for the effective development of shale oil. Therefore, there is an urgent need to provide an experimental apparatus and method for evaluating the permeability of the tight core matrix, thus providing fundamental research for the effective development of oil wells. Summary of the Invention

[0003] To address the above-mentioned problems, one of the objectives of this invention is to provide an experimental device for evaluating the permeability and absorption capacity of dense core matrix.

[0004] To achieve the above objectives, the present invention provides the following technical solution: An experimental device for evaluating the permeability of dense core matrix includes a first container, a second container, a connecting pipe, a core holder, an injection pump, a back pressure valve, and a confining pressure pump. The core holder and the connecting pipe are both located between the first container and the second container. The confining pressure pump is connected to the core holder through a first pipe, the injection pump is connected to the first container through a second pipe, and the back pressure valve is connected to the second container through a third pipe. A first volume measuring device is installed on the top of the first container, and a second volume measuring device is installed on the top of the second container; valves are installed on the first pipe, the second pipe, the third pipe, and the connecting pipe; pressure gauges are installed on the first pipe, the second pipe, and the third pipe.

[0005] Preferably, the pressure gauges include a first pressure gauge, a second pressure gauge, and a third pressure gauge, and the valves include a first valve, a second valve, a third valve, a fourth valve, and a fifth valve; The first pipeline is equipped with a first pressure gauge and a first valve; the second pipeline is equipped with a second pressure gauge and a second valve; the third pipeline is equipped with a third pressure gauge and a third valve; the connecting pipe is equipped with a fourth valve at the connection end with the first container; and the connecting pipe is equipped with a fifth valve at the connection end with the second container.

[0006] Preferably, the first volume measuring device and the second volume measuring device have the same structure, both including a visualization window, a scale and a measuring container; The measuring container is provided with a visual window, and the visual window is provided with scale.

[0007] Preferably, the core holder includes a sealing sleeve and a holder cylinder; The sealing sleeve is located inside the clamping cylinder, and the dense rock core is located inside the sealing sleeve.

[0008] Preferably, the experimental device for evaluating the permeability of dense core matrix further includes a constant temperature chamber, and the first container, the second container and the core holder are all placed inside the constant temperature chamber.

[0009] To address the aforementioned problems, a second objective of this invention is to provide a method for evaluating the permeability and absorption capacity of dense core matrix.

[0010] To achieve the above objectives, the present invention provides the following technical solution: A method for evaluating the permeability and absorption capacity of dense core matrix, the specific steps of which are as follows: Two dense rock cores with similar or identical physical properties were pretreated and then saturated with simulated oil. One of the dense cores was subjected to an isobaric test using the aforementioned dense core matrix permeation capacity evaluation experimental device to obtain the pressure and oil volume data of the first and second containers at a preset time N. Another dense core was subjected to an unequal pressure test using the aforementioned dense core matrix permeation capacity evaluation experimental device to obtain pressure and oil volume data of the first and second containers at a preset time N. Based on the pressure and oil volume data measured in the equal pressure and unequal pressure experiments, the contribution ratio η of permeation was calculated. N .

[0011] Preferably, the pretreatment of dense core includes: taking dense core samples, washing with oil, drying, weighing, and measuring porosity and permeability.

[0012] Preferably, the specific data obtained from the isobaric experiment at a preset time N are as follows: the pressure values ​​of both the first and second containers are P obtained by the pressure gauge. efN The oil volume V in the first container is obtained through the first volume measuring device. eN The oil volume V in the second container is obtained through the second volume metering device. fN ; The specific data obtained from the unequal pressure experiment at a preset time N are as follows: The pressure value of the first container is P obtained through the pressure gauge. aN The pressure values ​​of both the second and third containers are P. bNThe oil volume V in the first container is obtained through the first volume measuring device. aN The oil volume V in the second container is obtained through the second volume metering device. bN .

[0013] Preferably, the contribution ratio η of permeation is calculated based on the pressure and oil volume data obtained from equal pressure experiments and unequal pressure experiments. N The specific process is as follows: According to P efN V eN V fN The reference pressure in the pressure calculation experiment is P. x Total oil volume V at time xN ; According to P aN V aN P bN V bN The reference pressure in the unequal pressure calculation experiment is P. x Total oil volume V at time abN ; According to V xN and V abN η was calculated N .

[0014] Preferably, the contribution ratio η of percolation is calculated. N The specific process is as follows: According to P efN V eN V fN Value calculation V xN The formula is as follows: ; According to P aN V aN P bN V bN Value calculation V abN The formula is as follows: ; According to V xN and V abN η was calculated N The formula is as follows: .

[0015] The beneficial effects of this invention are as follows: The experimental apparatus and method for evaluating the permeability of tight core matrix of the present invention can effectively evaluate the permeability and contribution of tight matrix (the contribution ratio of permeation), thereby providing basic research for the effective development of oil wells.

[0016] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description, claims and drawings. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic diagram of the structure of the experimental device for evaluating the permeability and absorption capacity of dense core matrix of the present invention is shown; Figure 2 A schematic diagram of the core holder of the present invention is shown; Figure 3 A schematic diagram of the structure of the first volume measuring device or the second volume measuring device of the present invention is shown; In the attached figures: 1-Containing pressure pump, 2-First pressure gauge, 3-First volumetric measuring device, 4-Constant temperature chamber, 5-Second pressure gauge, 6-Injection pump, 7-Second valve, 8-First container, 9-Fourth valve, 10-Connecting pipe, 11-Fifth valve, 12-Third valve, 13-Back pressure valve, 14-Third pressure gauge, 15-Second container, 16-Second volumetric measuring device, 17-Core holder, 18-Dense core, 19-First valve, 20-Sealing sleeve, 21-Holder cylinder, 22-Visual window, 23-Scale, 24-Measuring container. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] like Figure 1 As shown: This invention discloses an experimental device for evaluating the permeability of a dense core matrix, including a first container 8, a second container 15, a connecting pipe 10, a core holder 17, an injection pump 6, a back pressure valve 13, and a confining pressure pump 1. The core holder 17 and the connecting pipe 10 are both located between the first container 8 and the second container 15. The confining pressure pump 1 is connected to the core holder 17 through the first pipe, the injection pump 6 is connected to the first container 8 through the second pipe, and the back pressure valve 13 is connected to the second container 15 through the third pipe. A first volume measuring device 3 is installed on the top of the first container 8, and a second volume measuring device 16 is installed on the top of the second container 15. Valves are installed on the first pipe, the second pipe, the third pipe, and the connecting pipe 10. Pressure gauges are installed on the first pipe, the second pipe, and the third pipe.

[0021] The experimental device for evaluating the permeability of tight core matrix of the present invention can be used to calculate the effective evaluation of the permeability of tight matrix and the magnitude of permeation contribution (permeation contribution ratio) by using experimental data obtained from equal pressure experiments and unequal pressure experiments, thereby providing basic research for the effective development of oil wells.

[0022] Specifically, the pressure gauges include a first pressure gauge 2, a second pressure gauge 5, and a third pressure gauge 14; the valves include a first valve 19, a second valve 7, a third valve 12, a fourth valve 9, and a fifth valve 11; wherein, the first pressure gauge 2 and the first valve 19 are installed on the first pipeline; the second pressure gauge 5 and the second valve 7 are installed on the second pipeline; the third pressure gauge 14 and the third valve 12 are installed on the third pipeline; the fourth valve 9 is installed at the connection end between the connecting pipe 10 and the first container 8; and the fifth valve 11 is installed at the connection end between the connecting pipe 10 and the second container 15.

[0023] The closure of the first pipe, second pipe, third pipe, and connecting pipe 10 is controlled by setting the first valve 19, the second valve 7, the third valve 12, the fourth valve 9, and the fifth valve 11. The pressure of the first container 8, the second container 15, and the core holder 17 is monitored and measured by setting the first pressure gauge 2, the second pressure gauge 5, and the third pressure gauge 14.

[0024] Preferably, such as Figure 3 As shown: The first volume measuring device 3 and the second volume measuring device 16 have the same structure, both including a visualization window 22, a scale 23 and a measuring container 24; The measuring container 24 is provided with a visualization window 22, and the visualization window 22 is provided with a scale 23.

[0025] The oil volume of the first container 8 and the second container 15 is measured by setting the first volume measuring device 3 and the second volume measuring device 16.

[0026] Preferably, such as Figure 2As shown: The core holder 17 includes a sealing sleeve 20 and a holder cylinder 21; wherein, the sealing sleeve 20 is disposed inside the holder cylinder 21, and the dense core 18 is located inside the sealing sleeve 20. The core holder 17 is used to hold the dense core 18.

[0027] Preferably, the experimental apparatus for evaluating the permeability of dense core matrix of the present invention further includes a constant temperature chamber 4, wherein the first container 8, the second container 15, and the core holder 17 are all disposed within the constant temperature chamber 4. By setting up the constant temperature chamber 4, the temperature of the first container 8, the second container 15, and the core holder 17 during the experiment is adjusted to maintain a constant temperature during the experiment.

[0028] This invention also discloses a method for evaluating the permeability and absorption capacity of dense core matrix, the specific steps of which are as follows: S1 Take two dense rock cores with the same or similar physical properties and saturate them with simulated oil after pretreatment. Preferably, the pretreatment of dense rock cores includes: washing the dense rock cores with oil, drying, weighing, and measuring porosity and permeability.

[0029] S2 uses the above-mentioned dense core matrix permeation capacity evaluation experimental device to conduct an isobaric test on one of the dense cores to obtain the pressure and oil volume data of the first container 8 and the second container 15 at a preset time N. Another dense core was subjected to an unequal pressure test using the aforementioned dense core matrix permeation capacity evaluation experimental device to obtain pressure and oil volume data of the first container 8 and the second container 15 at a preset time N. The specific details regarding the equal pressure experiment and the unequal pressure experiment are explained below: Pressure equalization experiment: The pressures in the first container 8 and the second container 15 are equal; the experimental pressure P n Experimental temperature T n Unequal pressure experiment: The pressures in the first container 8 and the second container 15 are not equal; the experimental temperature T n The first container 8 test pressure P n The second container, 15, experimental pressure P n-1 (P) n-1 <P n ).

[0030] Isobaric test: A dense core 18 saturated with simulated oil is placed inside the core holder 17; the constant temperature chamber 4 is opened to bring the temperature of the chamber to the preset value T. n Turn on the confining pressure pump 1, and after the confining pressure reaches the preset value by observing the first pressure gauge 2, age for 3 days; open the fourth valve 9 and the fifth valve 11 to connect the first container 8 and the second container 15; open the injection pump 6 and the second valve 7, close the third valve 12, and after observing the second pressure gauge 5 and the third pressure gauge 14, ensure that the pressure values ​​both reach the preset pressure value P.n According to Table 1, read and record the pressure value P of the third pressure gauge 14 at different preset time points 1, 2, 3, ..., N. ef1 P ef2 P ef3 ... P efN The oil volume V of the first volume metering device 3 e1 V e2 V e3 V eN The oil volume V of the second volume metering device 16 f1 V f2 V f3 V fN Record the above data in Table 1.

[0031] Table 1. Data from the Isobaric Test

[0032] Unequal pressure test: Place another dense core 18 saturated with oil into the core holder 17; turn on the constant temperature chamber 4 to bring the temperature of the constant temperature chamber 4 to the same preset value T as the temperature of the equal pressure test. n Turn on the confining pressure pump 1, and after the confining pressure reaches the preset value by observing the first pressure gauge 2, age for 3 days; open the fourth valve 9 and the fifth valve 11 to connect the first container 8 and the second container 15; open the injection pump 6 and the second valve 7, and observe the third pressure gauge 14. When the pressure value of the third pressure gauge 14 reaches the preset pressure value P... n-1 At this time, close the fourth valve 9 and the fifth valve 11, open the third valve 12, and set the back pressure valve 13 to control the pressure to the current pressure value P displayed on the third pressure gauge 14. n-1 Observe the second pressure gauge 5 and ensure that the pressure value on the second pressure gauge 5 reaches the preset pressure value P. n According to Table 2, read and record the pressure values ​​P of the second pressure gauge 5 at different preset time points 1, 2, 3, ..., N. a1 P a2 P a3 ... P aN The pressure value P of the third pressure gauge 14 b1 P b2 P b3 ... P bN ; the oil volume V of the first volume metering device 3 a1 V a2 V a3 V aN The oil volume V of the second volume metering device 16 b1 V b2 V b3 VbN .

[0033] Table 2. Data from the Unequal Pressure Experiment

[0034] S3 calculates the contribution ratio η of permeation based on the pressure and oil volume data obtained from the isobaric and unequal pressure experiments. N； Calculate the contribution ratio η of percolation N The specific process is as follows: First, let's introduce the existing formula (1) as follows:

[0035] In the formula, C0 is the isothermal compressibility coefficient of crude oil, which can be obtained through indoor experiments and is measured in MPa. -1 P1 and P2 are pressures in MPa; V1 is the volume of crude oil at pressure P1 in m³. 3 V2 represents the volume of crude oil at pressure P2, in cubic meters (m³). 3 ; According to P efN V eN V fN Combining the value with the above formula (1), the reference pressure in the pressure equalization experiment is obtained as P. x Total oil volume V at time xN Formula (2) is as follows: (2) According to P aN V aN P bN V bN Combining the value with Formula 1 above, the reference pressure P in the unequal pressure experiment is obtained. x Total oil volume V at time abN Formula (3) is as follows:

[0036] According to V xN and V abN η was calculated N Formula (4) is as follows: .

[0037] It should be noted that P appears in the text. x The reference pressure can be set to, for example, 1 atmosphere as needed.

[0038] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for evaluating the permeability and absorption capacity of a dense core matrix, characterized in that: The specific steps are as follows: Two dense rock cores with similar or identical physical properties were pretreated and then saturated with simulated oil. One of the dense cores was subjected to an isobaric test to obtain the pressure and oil volume data of the first container (8) and the second container (15) at a preset time N. Another dense core was subjected to an unequal pressure test to obtain the pressure and oil volume data of the first container (8) and the second container (15) at a preset time N; Based on the pressure and oil volume data measured in the equal pressure and unequal pressure experiments, the contribution ratio η of permeation was calculated. N ; The specific data obtained from the isobaric experiment at a preset time N are as follows: The pressure values ​​of the first container (8) and the second container (15) were both P obtained by the pressure gauge. efN The oil volume V of the first container (8) is obtained through the first volume measuring device (3). eN The oil volume V of the second container (15) is obtained through the second volume metering device (16). fN ; The specific data obtained from the unequal pressure experiment at the preset time N are as follows: The pressure value of the first container (8) is P obtained by the pressure gauge. aN The pressure values ​​of the second container (15) are both P bN The oil volume V of the first container (8) is obtained through the first volume measuring device (3). aN The oil volume V of the second container (15) is obtained through the second volume metering device (16). bN ; The contribution ratio η of permeation is calculated based on the pressure and oil volume data obtained from equal pressure and unequal pressure experiments. N The specific process is as follows: According to P efN V eN V fN The reference pressure in the pressure calculation experiment is P. x Total oil volume V at time xN ; According to P aN V aN P bN V bN The reference pressure in the unequal pressure calculation experiment is P. x Total oil volume V at time abN ; According to V xN and V abN η was calculated N ; The contribution ratio η of percolation was calculated. N The specific process is as follows: According to P efN V eN V fN Value calculation V xN The formula is as follows: ； in, C 0 represents the isothermal compressibility coefficient of crude oil; According to P aN V aN P bN V bN Value calculation V abN The formula is as follows: ； According to V xN and V abN η was calculated N The formula is as follows: 。 2. The method for evaluating the permeability and absorption capacity of a dense core matrix according to claim 1, characterized in that: Pretreatment of dense cores includes: taking dense cores, washing oil, drying, weighing, and measuring porosity and permeability.

3. The method for evaluating the permeability and absorption capacity of a dense core matrix according to claim 1, characterized in that: It includes a first container (8), a second container (15), a connecting pipe (10), a core holder (17), an injection pump (6), a back pressure valve (13), and a confining pressure pump (1); The core holder (17) and the connecting pipe (10) are both located between the first container (8) and the second container (15); The confining pressure pump (1) is connected to the core holder (17) through the first pipe, the injection pump (6) is connected to the first container (8) through the second pipe, and the back pressure valve (13) is connected to the second container (15) through the third pipe. The first container (8) is provided with a first volume measuring device (3) on its top, and the second container (15) is provided with a second volume measuring device (16) on its top; valves are provided on the first pipe, the second pipe, the third pipe and the connecting pipe (10); pressure gauges are provided on the first pipe, the second pipe and the third pipe.

4. The method for evaluating the permeability of a dense core matrix according to claim 3, characterized in that: The pressure gauges include a first pressure gauge (2), a second pressure gauge (5) and a third pressure gauge (14), and the valves include a first valve (19), a second valve (7), a third valve (12), a fourth valve (9) and a fifth valve (11). The first pipeline is equipped with a first pressure gauge (2) and a first valve (19); the second pipeline is equipped with a second pressure gauge (5) and a second valve (7); the third pipeline is equipped with a third pressure gauge (14) and a third valve (12); the connecting pipe (10) is equipped with a fourth valve (9) at the connection end with the first container (8), and the connecting pipe (10) is equipped with a fifth valve (11) at the connection end with the second container (15).

5. The method for evaluating the permeability and absorption capacity of a dense core matrix according to claim 3, characterized in that: The first volume measuring device (3) and the second volume measuring device (16) have the same structure, both including a visualization window (22), a scale (23) and a measuring container (24). The measuring container (24) is provided with a visualization window (22), and the visualization window (22) is provided with a scale (23).

6. The method for evaluating the permeability and absorption capacity of a dense core matrix according to claim 3, characterized in that: The core holder (17) includes a sealing sleeve (20) and a holder cylinder (21). The sealing sleeve (20) is located inside the clamp cylinder (21), and the dense core (18) is located inside the sealing sleeve (20).

7. The method for evaluating the permeability and absorption capacity of a dense core matrix according to claim 3, characterized in that: It also includes a constant temperature chamber (4), and the first container (8), the second container (15) and the core holder (17) are all set inside the constant temperature chamber (4).

Images