Oil reservoir recovery degree evaluation method

Abstract

The invention discloses an oil reservoir recovery degree evaluation method in the technical field of oil reservoir recovery detection, and the method comprises the following steps: communicating a detection assembly on the side surface of an oil extraction pipeline, enabling crude oil circulating in the oil extraction pipeline to pass through the detection assembly, and enabling the detection assembly to operate at intervals according to a preset detection period; when the detection assembly operates, the crude oil in the detection assembly is stirred, the detection output voltage of the crude oil is kept through a detection circuit in the detection assembly, and the maximum voltage [mu] m is output; obtaining a voltage effective value ui according to the maximum voltage [mu] m; then, according to the voltage effective value ui, the dielectric constant epsilon of the crude oil-water mixture is obtained; and finally, according to the dielectric constant epsilon of the crude oil-water mixture, the dielectric constant epsilon o of the pure crude oil, the dielectric constant epsilon f of the pure water and the final oil recovery rate Rm of the oil reservoir, obtaining the oil recovery rate R of the oil reservoir. According to the method, the oil reservoir recovery degree can be conveniently and accurately obtained on line in real time, and tedious sampling, detection and other steps are not needed.

Description

Technical Field

[0001] The invention belongs to the technical field of oil reservoir production detection, in particular to an oil reservoir production degree evaluation method. Background Art

[0002] The degree of oil recovery refers to the percentage of the cumulative oil production of an oil field to its geological reserves. The degree of recovery is an important indicator for measuring the recovery effect of an oil field. The higher the degree of recovery, the better the recovery effect of the oil field, and vice versa. Therefore, accurately evaluating the degree of oil recovery can accurately reflect the recovery effect of the oil field.

[0003] There are many methods for evaluating the recovery degree of oil reservoirs in the prior art. For example, a method for testing the recovery degree of gas-water coordinated injection partitions in inclined oil reservoirs described in Chinese patent document CN111878075B includes: preparing a formation crude oil sample, dividing it into oil sample 1 and oil sample 2 by volume, adding mesitylene to oil sample 1, and testing the molar concentration of mesitylene; loading two groups of long cores into core holder 1 and core holder 2 respectively; calculating the total pore volume of the two groups of long cores and the surface volume of crude oil in the two groups of long cores; injecting formation water from the inlet end of core holder 1, and injecting injection gas from the inlet end of core holder 2; recording the oil volume of the separator at this stage for each injection of 0.05Vp volume of gas and 0.05Vp volume of formation water, and testing the molar concentration of mesitylene in the oil sample, and driving until no oil can be produced at the outlet; and drawing a curve of the recovery degree changing with the cumulative injected pore volume multiple.

[0004] The above technical solution requires tedious manual operations in the testing process of oil reservoir recovery degree, and may introduce human errors in the sampling and sample preparation process, thereby affecting the accuracy and reliability of the monitoring results; therefore, there is an urgent need for a method that can conveniently and accurately evaluate the recovery degree of oil reservoirs. Summary of the invention

[0005] The purpose of the present invention is to provide a method for evaluating the recovery rate of oil reservoirs, so as to solve the problem that the convenience and accuracy of evaluating the recovery rate of oil reservoirs are limited.

[0006] In order to achieve the above-mentioned object, the technical scheme of the present invention is as follows: A method for evaluating the recovery degree of an oil reservoir comprises the following steps: connecting a detection component to the side of an oil production pipeline, so that the crude oil flowing in the oil production pipeline passes through the detection component, and the detection component operates according to a preset detection cycle interval;

[0007] When the detection component is running, the crude oil inside it is stirred, and the detection circuit inside it keeps detecting the crude oil output voltage, and the maximum output voltage is u m ;

[0008] Then according to the maximum voltage u m , get the voltage effective value ui ;

[0009] Then according to the voltage effective value u i , obtain the dielectric constant ε of crude oil-water mixture;

[0010] Finally, based on the dielectric constant ε of crude oil-water mixture and the dielectric constant ε of pure crude oil, o 、The dielectric constant of pure water ε f and the ultimate oil recovery factor R m Get the oil recovery degree R in the reservoir.

[0011] Further, according to the maximum voltage u m , get the voltage effective value u i , obtained by the following formula:

[0012]

[0013] Among them, u i is the effective value of voltage during the detection process, u m It is the maximum voltage during the detection process.

[0014] Further, according to the voltage effective value u i , obtain the dielectric constant ε of crude oil-water mixture, which is obtained by the following formula:

[0015] ε=0.03e 2.3021 u i

[0016] Where ε is the dielectric constant of crude oil-water mixture, u i It is the effective value of voltage during the detection process.

[0017] Furthermore, based on the dielectric constant ε of crude oil-water mixture and the dielectric constant ε of pure crude oil o 、The dielectric constant of pure water ε f and the ultimate oil recovery factor R m The oil recovery degree R in the reservoir is obtained by the following formula:

[0018]

[0019] Among them, ε o is the dielectric constant of pure crude oil, ε f is the dielectric constant of pure water, R m is the ultimate oil recovery factor of the reservoir, and R is the degree of oil recovery in the reservoir.

[0020] Furthermore, during the operation of the detection component, the connection with the oil production pipe is closed, and when the detection component is completed, the maximum voltage u is output through the detection circuit. mAfter that, the connection with the oil production pipe is opened, so that the crude oil flowing through the detection component in the oil production pipe continues to pass through the detection component.

[0021] Further, the detection assembly includes a detection sleeve fixedly connected to the side of the oil production pipe, the detection sleeve is communicated with the inside of the oil production pipe, a connecting plate is fixedly connected to one end of the detection sleeve away from the oil production pipe, the connecting plate is rotatably connected to a detection shaft, a first detection plate and a second detection plate are fixedly connected to the detection shaft, the first detection plate and the second detection plate are not in contact, the connecting plate is fixedly connected to a driving member, and an output shaft of the driving member is coaxially and fixedly connected to the detection shaft;

[0022] The detection circuit includes a first detection cable electrically connected to the first detection board and a second detection cable electrically connected to the second detection board;

[0023] By receiving the electrical signals of the first detection cable and the second detection cable, the real-time voltage value is output according to the voltage value. m .

[0024] Furthermore, the first detection plate is parallel to the second detection plate, and both the first detection plate and the second detection plate are composed of a plurality of conductive rods.

[0025] Furthermore, the first detection cable and the second detection cable are both extended outside the detection sleeve, the connection plate is fixedly connected with a slip ring, and the first detection cable and the second detection cable are electrically connected to the first detection plate and the second detection plate respectively through the slip ring.

[0026] Furthermore, a solenoid valve is provided at the connection point between the detection casing and the oil production pipe, and the operation of the solenoid valve is controlled according to the user input instruction.

[0027] The above scheme has the following beneficial effects:

[0028] 1. The present invention uses the crude oil between the first detection plate and the second detection plate as a dielectric. When the water content of the crude oil changes, the dielectric changes, thereby causing the capacitance value between the first detection plate and the second detection plate to change. The detection circuit detects the output voltage of the capacitor formed by the first detection plate and the second detection plate, and the effective voltage during the operation of the detection component is obtained. Through the corresponding acquisition formula, the oil reservoir recovery degree can be conveniently and accurately obtained online in real time. Compared with the prior art, the present invention can conveniently evaluate the oil reservoir recovery degree online without the need for cumbersome sampling, detection and other steps.

[0029] 2. In the present invention, during the process of testing crude oil, the crude oil is stirred for testing. On the one hand, it can promote better contact and mixing of water and oil, thereby improving the uniformity of oil-water mixing and improving the accuracy of detection data of the detection line; on the other hand, stirring can better disperse the tiny water droplets or water analysis particles dispersed therein into the solution, increase the contact area between the water phase and the oil phase, which thereby improves the reactivity between the water analysis components and the detection method, and further improves the sensitivity of the detection.

[0030] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a flow chart of an embodiment of the method for evaluating the degree of oil reservoir recovery of the present invention;

[0032] Figure 2 It is a schematic diagram of the structure of the detection component of an embodiment of the method for evaluating the recovery degree of oil reservoirs of the present invention;

[0033] Figure 3 This is a cable connection diagram of an embodiment of the method for evaluating oil reservoir recovery degree of the present invention. DETAILED DESCRIPTION

[0034] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0035] The following is further described in detail through specific implementation methods:

[0036] The reference numerals in the drawings of the specification include: a detection sleeve 1 , a first detection plate 2 , a first detection cable 3 , a second detection cable 4 , a connecting plate 5 , a driving member 6 , a second detection plate 7 , and a detection shaft 8 .

[0037] Implementation example Figure 1-Figure 3 As shown: A method for evaluating the degree of oil reservoir recovery, the method comprises the following steps:

[0038] (1) Connect the detection component 101 on the side of the oil production pipeline so that the crude oil flowing in the oil production pipeline passes through the detection component 101. The detection component 101 operates according to a preset detection cycle interval; the detection cycle is the frequency of the oil reservoir recovery evaluation. The user can set the detection cycle according to the output evaluation rate of the oil reservoir recovery evaluation.

[0039] (2) When the detection component 101 is in operation, the crude oil inside it is stirred, and the detection circuit 102 inside it keeps detecting the crude oil and outputting the voltage, and the maximum output voltage u m The operation of the detection component 101 is a time period, and the detection circuit 102 continuously outputs multiple voltage values ​​during the operation period of the detection component 101, and selects the maximum voltage u m .

[0040] (3) According to the maximum voltage u m , get the voltage effective value u i ; Obtained by the following formula:

[0041]

[0042] Among them, u i is the effective value of voltage during the detection process, u m It is the maximum voltage during the detection process.

[0043] (4) According to the voltage effective value u i , obtain the dielectric constant ε of crude oil-water mixture; obtain it through the following formula:

[0044] ε=0.03e 2.3021 u i

[0045] Where ε is the dielectric constant of crude oil-water mixture, u i is the effective value of voltage during the detection process; the constants 0.30 and 2.33021 are obtained through multiple experiments based on the proposed evaluation reservoir. Specifically, the voltage and water content of crude oil produced from the detection reservoir are tested multiple times, and the functional relationship between the dielectric constant ε of the crude oil-water mixture that meets the proposed evaluation reservoir and the effective value of voltage is obtained by fitting based on the voltage and water content tested multiple times.

[0046] (5) Based on the dielectric constant ε of crude oil-water mixture and the dielectric constant ε of pure crude oil o 、The dielectric constant of pure water ε f and the ultimate oil recovery factor R m Obtain the oil recovery degree R in the reservoir; obtain it through the following formula:

[0047]

[0048] Among them, ε o is the dielectric constant of pure crude oil, ε f is the dielectric constant of pure water, R m is the ultimate oil recovery factor of the reservoir, and R is the degree of oil recovery in the reservoir.

[0049] Secondly, in order to reduce the impact of the crude oil continuously flowing through the detection component 101 on the evaluation results, the connection between the detection component 101 and the oil production pipe is closed during operation, and the detection component 101 is completed and the maximum voltage u is output through the detection circuit 102. m Afterwards, the connection with the oil production pipe is opened, so that the crude oil flowing through the detection component 101 in the oil production pipe continues to pass through the detection component 101.

[0050] Specifically, the detection assembly 101 includes a detection sleeve 1 fixedly connected to the side of the oil production pipe, the detection sleeve 1 is connected to the inside of the oil production pipe, and the detection sleeve 1 is fixedly connected to a connecting plate 5 at one end away from the oil production pipe. The connecting plate 5 is rotatably connected to a detection shaft 8, and a first detection plate 2 and a second detection plate 7 are fixedly connected to the detection shaft 8. The first detection plate 2 and the second detection plate 7 are not in contact with each other. The connecting plate 5 is fixedly connected to a driving member 6. The driving member 6 of this embodiment is a servo motor, and the output shaft of the driving member 6 is coaxially fixedly connected to the detection shaft 8.

[0051] A solenoid valve is provided at the connection point between the detection casing 1 and the oil production pipe, and the operation of the solenoid valve is controlled according to the user input instruction.

[0052] Preferably, the first detection plate 2 is parallel to the second detection plate 7 , and both the first detection plate 2 and the second detection plate 7 are composed of a plurality of conductive rods, and the positions of the conductive rods of the first detection plate 2 and the second detection plate 7 are arranged in a one-to-one correspondence.

[0053] The detection circuit 102 includes a first detection cable 3 electrically connected to the first detection board 2 and a second detection cable 4 electrically connected to the second detection board 7. The first detection cable 3 and the second detection cable 4 both extend to the outside of the detection sleeve 1. The connecting plate 5 is fixedly connected with a slip ring. The first detection cable 3 and the second detection cable 4 are electrically connected to the first detection board 2 and the second detection board 7 respectively through the slip ring.

[0054] By receiving the electrical signals of the first detection cable 3 and the second detection cable 4, the real-time voltage value is output according to the voltage value. m , and controls the operation of the drive element 6 according to the user input command. The voltage output acquisition part can be carried out by using the UIS1200 capacitive sensor detection controller. For details, please refer to the attached Figure 3 , connect the first detection cable 3 and the second detection cable 4 to the UIS1200 capacitive sensor detection controller.

[0055] Specifically, the driving member 6 is controlled to operate according to the detection cycle preset by the user, so that the conductive rods on the first detection plate 2 and the conductive rods on the second detection plate 7 synchronously stir the crude oil in the detection casing 1, and the real-time voltage value output by the controller during the stirring process is output through the first detection cable 3, the second detection cable 4 and the UIS1200 capacitive sensor, and the maximum voltage value u is selected from them.m ; Then, the oil recovery degree R in the reservoir is obtained through the following formulas:

[0056]

[0057] Among them, u i is the effective value of voltage during the detection process, u m is the maximum voltage during the detection process;

[0058] ε=0.03e 2.3021 u i

[0059] Where ε is the dielectric constant of crude oil-water mixture, u i It is the effective value of voltage during the detection process;

[0060]

[0061] Among them, ε o is the dielectric constant of pure crude oil, ε f is the dielectric constant of pure water, R m is the ultimate oil recovery factor of the reservoir, and R is the degree of oil recovery in the reservoir.

[0062] The above is only an embodiment of the present invention, and the common knowledge such as the known specific structure and / or characteristics in the scheme is not described in detail here. It should be pointed out that for those skilled in the art, several deformations and improvements can be made without departing from the structure of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A method for evaluating the degree of recovery of an oil reservoir, characterized in that: The method comprises the following steps: connecting the detection component at the side of the oil production pipeline so that the crude oil flowing in the oil production pipeline passes through the detection component, and the detection component operates according to a preset detection cycle interval; When the detection component is running, the crude oil inside it is stirred, and the detection circuit inside it keeps detecting the crude oil output voltage, and the maximum output voltage is u m ; Then according to the maximum voltage u m , get the voltage effective value u i ; Then according to the voltage effective value u i , obtain the dielectric constant ε of crude oil-water mixture; Finally, based on the dielectric constant ε of crude oil-water mixture and the dielectric constant ε of pure crude oil, o 、The dielectric constant of pure water ε f and the ultimate oil recovery factor R m Get the oil recovery degree R in the reservoir.

2. The method for evaluating oil reservoir recovery degree according to claim 1, characterized in that: According to the maximum voltage u m , get the voltage effective value u i , obtained by the following formula: Among them, u i is the effective value of voltage during the detection process, u m It is the maximum voltage during the detection process.

3. The method for evaluating oil reservoir recovery degree according to claim 2, characterized in that: According to the voltage effective value u i , obtain the dielectric constant ε of crude oil-water mixture, which is obtained by the following formula: ε=0.03e 2.3021 you i Where ε is the dielectric constant of crude oil-water mixture, u i It is the effective value of voltage during the detection process.

4. The method for evaluating oil reservoir recovery degree according to claim 3, characterized in that: Based on the dielectric constant ε of crude oil-water mixture and combined with the dielectric constant ε of pure crude oil o 、The dielectric constant of pure water ε f and the ultimate oil recovery factor R m The oil recovery degree R in the reservoir is obtained by the following formula: Among them, ε o is the dielectric constant of pure crude oil, ε f is the dielectric constant of pure water, R m is the ultimate oil recovery factor of the reservoir, and R is the degree of oil recovery in the reservoir.

5. The method for evaluating oil reservoir recovery degree according to claim 4, characterized in that: During the operation of the detection component, the connection with the oil production pipe will be closed. After the detection component is completed, the maximum voltage u will be output through the detection circuit. m After that, the connection with the oil production pipe is opened, so that the crude oil flowing through the detection component in the oil production pipe continues to pass through the detection component.

6. A method for evaluating the degree of recovery of an oil reservoir, characterized in that: The detection assembly includes a detection sleeve fixedly connected to the side of the oil production pipe, the detection sleeve is communicated with the inside of the oil production pipe, the detection sleeve is fixedly connected to a connecting plate at one end away from the oil production pipe, the connecting plate is rotatably connected to a detection shaft, a first detection plate and a second detection plate are fixedly connected to the detection shaft, the first detection plate and the second detection plate are not in contact, the connecting plate is fixedly connected to a driving member, and an output shaft of the driving member is coaxially and fixedly connected to the detection shaft; The detection circuit includes a first detection cable electrically connected to the first detection board and a second detection cable electrically connected to the second detection board; By receiving the electrical signals of the first detection cable and the second detection cable, the real-time voltage value is output according to the voltage value. m .

7. The method for evaluating oil reservoir recovery degree according to claim 6, characterized in that: The first detection plate is parallel to the second detection plate, and both the first detection plate and the second detection plate are composed of a plurality of conductive rods.

8. The method for evaluating oil reservoir recovery degree according to claim 7, characterized in that: The first detection cable and the second detection cable both extend outside the detection sleeve, the connection plate is fixedly connected with a slip ring, and the first detection cable and the second detection cable are electrically connected to the first detection plate and the second detection plate respectively through the slip ring.

9. The method for evaluating oil reservoir recovery degree according to claim 8, characterized in that: A solenoid valve is provided at the connection point between the detection casing and the oil production pipe, and the operation of the solenoid valve is controlled according to the user input command.

Images