An oil-gas-water multi-medium interface detection system and method

Abstract

The application discloses an oil-gas-water multi-medium interface detection system and method, and belongs to the field of multiphase flow parameter measurement. The system comprises a conductance array, a multi-channel excitation module, a multi-channel signal synchronous acquisition module and a control module. The conductance array comprises a plurality of embedded metal rings with their center points arranged on the same line and equidistantly arranged along the pipeline direction. The metal rings with odd numbers are connected with the positive poles of the multi-channel excitation module and the input channels of the multi-channel signal synchronous acquisition module, and the metal rings with even numbers are connected with the negative poles of the multi-channel excitation module. The multi-channel excitation module and the multi-channel signal synchronous acquisition module are connected with the control module. The control module determines the position of the oil-gas-water multi-medium interface according to the signal change speed and the amplitude difference of the output signal of the multi-channel signal synchronous acquisition module by using the oil-gas-water multi-medium interface detection method. The application can effectively realize accurate identification of the multi-medium interface formed in the static detection process of the oil-gas-water multiphase flow.

Description

Technical Field

[0001] This invention relates to the field of multiphase flow parameter measurement, and in particular to a system and method for detecting the interface between oil, gas and water media. Background Technology

[0002] During oil extraction, crude oil produced from oil fields generally contains both water and gas. Furthermore, the water and gas content changes with continuous oilfield extraction. Detecting the content of each phase in multiphase flow is crucial for calculating oilfield production and adjusting production plans. Among these methods, the static measurement method using a quick-closing valve is widely used due to its high reliability and accuracy.

[0003] Interfacial detection is both a key focus and a challenge in determining the phase content of oil-gas-water multiphase flows using the quick-closing valve method. Common methods for measuring interfacial components in oil-gas-water multiphase flows include conductivity array methods and capacitance array methods. However, due to the similar electrical properties of oil and gas, existing methods are less effective at detecting the oil-gas interface. Therefore, a new detection system and method are needed to better detect the locations of the interfaces in a gasoline-water three-phase mixture. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a system and method for detecting the interface between oil, gas and water in a multi-phase flow, so as to achieve accurate identification of the oil-water and oil-gas interfaces in the static detection of oil-gas-water multiphase flow.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: an oil-gas-water multi-media interface detection system, including a detection module, a solenoid valve at the top of the detection module and a one-way valve at the bottom, the detection module including a conductivity array, the conductivity array being connected to a multi-channel excitation module and a multi-channel signal synchronous acquisition module, the multi-channel excitation module and the multi-channel signal synchronous acquisition module being connected to a control module.

[0006] A further improvement of the technical solution of the present invention is that: the conductivity array includes an installation pipe and multiple embedded metal rings whose center points are on the same straight line and are equidistantly arranged along the pipe direction; a pressure-resistant protective shell is provided outside the installation pipe, the pressure-resistant protective shell is injection molded and is completely fitted to the installation pipe of the conductivity array 105.

[0007] A further improvement of the technical solution of this invention is as follows: the number of embedded metal rings is 2N, the multi-channel excitation module includes N independent excitation output channels with positive terminals and 1 output negative terminal shared by all channels, and all channels can output excitation synchronously; the multi-channel signal synchronous acquisition module includes N independent input channels that can be synchronously converted, thereby synchronously acquiring signals from all input channels; the metal rings are numbered sequentially from top to bottom in ascending order, with each pair of metal rings forming a group. In each group, the metal rings with odd numbers are connected to both the positive terminal of the corresponding excitation output channel of the multi-channel excitation module and the corresponding input channel of the multi-channel signal synchronous acquisition module, while the metal rings with even numbers are only connected to the negative output terminal of the multi-channel excitation module.

[0008] A further improvement of the technical solution of the present invention is that the multi-channel excitation module, the multi-channel signal synchronous acquisition module and the control module are all housed in the control box.

[0009] A method for detecting the interface between oil, gas, and water media, comprising the following steps:

[0010] Step 1: Open the check valve and solenoid valve. In the initial state, the three-phase fluid of oil, gas and water flows into and fills the conductive array.

[0011] Step 2: Close the solenoid valve. The three-phase fluid of oil, gas and water in the conductivity array stops flowing, and the oil, gas and water move freely under the influence of gravity.

[0012] Step 3: Synchronously excite all metal rings using a multi-channel excitation module and synchronously acquire the response signals of all metal rings using a multi-channel signal synchronous acquisition module;

[0013] Step 4: Determine the location of the oil-gas interface based on the switching speed of different channels of the multi-channel signal synchronous acquisition module.

[0014] Step 5: Determine the location of the oil-water interface based on the stable amplitude of the output data from the multi-channel signal synchronous acquisition module;

[0015] A further improvement to the technical solution of the present invention is as follows: Step 4 is specifically as follows:

[0016] Step 4.1: Determine the formation time of the interface between the gas phase and the oil-water mixture after the solenoid valve is closed based on the jump speed of the output data of the multi-channel signal synchronous acquisition module;

[0017] Step 4.2: Based on the determined formation time of the interface between the gas phase and the oil-water mixture, calculate the number of conduction ring groups where the signal is in a stable state. When the oil-gas interface is located between a certain group of metal rings, the signal of this group of metal rings is stable and the amplitude is between the maximum and minimum values. The signals of the metal rings above it are stable and at the maximum value, while the signals of the lower groups are in a slow changing state or stable at the minimum value. When the oil-gas interface is located between two adjacent groups of metal rings, the response signals of the metal rings above it are stable and at the maximum value, while the signals of the lower groups are in a slow changing state or stable at the minimum value.

[0018] Step 4.3: Based on the number of the metal rings and the depth information of the corresponding positions of each coded metal ring in the conductivity array, determine the position and depth of the interface between the gas phase and the oil-water mixture. This position is the position of the oil-gas interface after the fluid stabilizes.

[0019] A further improvement to the technical solution of the present invention is as follows: Step 5 is specifically as follows:

[0020] Step 5.1: Determine the moment when the fluid stabilizes after the solenoid valve is closed based on the stabilization time of the data from the multi-channel signal synchronous acquisition module;

[0021] Step 5.2: Determine the corresponding metal ring number based on the amplitude difference of the multi-channel signal synchronous acquisition module data at the moment when the fluid is generally stable. When the oil-water interface is located between a certain group of metal rings, the signal of this group of metal rings is between the maximum and minimum values. When the oil-water interface is located between two adjacent groups of metal rings, the response signals of the metal rings above it are at the maximum value, and the signals of the metal rings below it are at the minimum value.

[0022] Step 5.3: Based on the metal ring number and the corresponding depth information of each coded metal ring in the conductivity array, determine the depth of the interface between the oil and water mixture. This position is the position of the oil-water interface after the fluid stabilizes.

[0023] The technological advancements achieved by this invention are as follows: by setting up a conductivity array, in which multiple embedded metal rings with their center points on the same straight line and equidistantly arranged along the pipe direction are set up, and the metal rings, excitation module, and acquisition module are connected in an orderly manner, the interface between various media can be effectively detected by utilizing the transformation and amplitude of the acquired signal, with high recognition accuracy and simple operation. Attached Figure Description

[0024] 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 only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the detection module of the present invention;

[0026] Figure 2 This is a schematic diagram of the overall structure of the detection system of the present invention;

[0027] Figure 3 This is a schematic diagram of the conductivity array structure during practical operation of the detection method of the present invention;

[0028] Figure 4 This is a schematic diagram of the signal response of the oil-gas interface, which is ultimately located between the fourth and fifth sets of conductive rings, and the oil-water interface, which is ultimately located between the sixth and seventh sets of conductive rings, taking 8 sets of conductive rings as an example.

[0029] Among them, 101, multi-channel excitation module; 102, control module; 103, multi-channel signal synchronous acquisition module; 104, control box; 105, conductivity array; 1051, first metal ring; 1052, second / Nth metal ring; 106, high-pressure resistant protective shell; 201, solenoid valve; 202, detection module; 203, one-way valve; 311, gas; 312, oil; 313, water; 321, oil-gas interface; 322, oil-water interface. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to embodiments:

[0031] like Figure 2 As shown in the diagram, the arrows indicate the direction of fluid flow. This is a schematic diagram of a multi-media interface detection system for oil, gas, and water, including a detection module 202. The detection module 202 has a solenoid valve 201 at its top and a check valve 203 at its bottom. The specific structure of the core detection module 202 is as follows... Figure 1 As shown, the system includes a conductivity array 105, which comprises an installation pipe and multiple embedded metal rings equidistantly arranged along the pipe direction with their center points aligned on the same straight line. The number of metal rings is 2N, with the topmost ring being the first metal ring 1051, the bottommost ring being the second-Nth metal ring 1052, and the intermediate rings numbered sequentially from smallest to largest. The conductivity array 105 is housed within a pressure-resistant protective shell 106. To address the high-temperature and high-pressure environment inside the oil well, the pressure-resistant protective shell 106 is injection-molded onto the outside of the conductivity array, ensuring a complete fit with the array. This results in a simple system structure with high reliability and long service life, meeting the needs of oil well production.

[0032] The conductivity array 105 is connected to the multi-channel excitation module 101 and the multi-channel signal synchronous acquisition module 103. Specifically, the multi-channel excitation module 101 includes N independent excitation output channels with positive terminals and one output negative terminal shared by all channels, and all channels can output excitation synchronously. The multi-channel signal synchronous acquisition module 103 includes N independent input channels that can be synchronously converted, and thus can synchronously acquire signals from all input channels. The metal rings are numbered sequentially from top to bottom, with each pair of metal rings forming a group. In each group, the metal rings with odd numbers are connected to both the positive terminal of the corresponding excitation output channel of the multi-channel excitation module 101 and the corresponding input channel of the multi-channel signal synchronous acquisition module 103, while the metal rings with even numbers are only connected to the negative output terminal of the multi-channel excitation module 101. The multi-channel excitation module 101 and the multi-channel signal synchronous acquisition module 103 are connected to the control module 102. The control module 102 controls the output of the multi-channel excitation module 101 and determines the interface position based on the signal acquired by the multi-channel signal synchronous acquisition module 103. The multi-channel excitation module 101, control module 102, and multi-channel signal synchronous acquisition module 103 are all installed inside the control box 104. They are used to generate excitation to drive the conductivity array and to acquire and analyze the conductivity array response signal to calculate the medium interface position, etc. The multi-channel excitation module 101 and the multi-channel signal synchronous acquisition module 103 are connected to the conductivity array 105 by wires. Their installation position can be adjusted according to the actual situation, that is, the control box 103 does not necessarily have to be installed on top of the pressure-resistant protective shell 106. The number of metal rings in the conductivity array 105 depends on the length of the oil-gas-water multiphase flow static measurement pipe section, the size of the metal rings, and the measurement accuracy requirements. Theoretically, the smaller the size of the metal rings, the denser they are, and the greater the number, the higher the measurement accuracy of the sensor.

[0033] The above-mentioned detection system can be used to detect multi-media interfaces. Specifically, a method for detecting oil-gas-water multi-media interfaces is as follows:

[0034] Step 1: Open the check valve and solenoid valve. In the initial state, the three-phase fluid of oil, gas and water flows into and fills the conductive array.

[0035] Step 2: Close the solenoid valve. The three-phase fluid of oil, gas and water in the conductivity array stops flowing, and the oil, gas and water move freely under the influence of gravity.

[0036] Step 3: Synchronously excite all metal rings using a multi-channel excitation module and synchronously acquire the response signals of all metal rings using a multi-channel signal synchronous acquisition module;

[0037] Step 4: Determine the location of the oil-gas interface based on the switching speed of different channels of the multi-channel signal synchronous acquisition module.

[0038] Step 4.1: Determine the formation time of the interface between the gas phase and the oil-water mixture after the solenoid valve is closed based on the jump speed of the output data of the multi-channel signal synchronous acquisition module;

[0039] Step 4.1: Determine the formation time of the interface between the gas phase and the oil-water mixture after the solenoid valve closes based on the jump rate of the output data from the multi-channel signal synchronous acquisition module. Figure 4 The time t1 is shown;

[0040] Step 4.2: Based on the determined formation time of the interface between the gas phase and the oil-water mixture, calculate the number of conduction ring groups where the signal is in a stable state. When the oil-gas interface is located between a certain group of metal rings, the signal of this group of metal rings is stable and the amplitude is between the maximum and minimum values. The signals of the metal rings above it are stable and at the maximum value, while the signals of the lower groups are in a slow changing state or stable at the minimum value. When the oil-gas interface is located between two adjacent groups of metal rings, the response signals of the metal rings above it are stable and at the maximum value, while the signals of the lower groups are in a slow changing state or stable at the minimum value.

[0041] Step 4.3: Based on the number of the metal rings and the depth information of the corresponding positions of each coded metal ring in the conductivity array, determine the position and depth of the interface between the gas phase and the oil-water mixture. This position is the position of the oil-gas interface after the fluid stabilizes.

[0042] Step 5: Determine the location of the oil-water interface based on the stable amplitude of the output data from the multi-channel signal synchronous acquisition module;

[0043] Step 5.1: Determine the moment when the fluid stabilizes after the solenoid valve closes, based on the stabilization time of the data from the multi-channel signal synchronous acquisition module. Figure 4 The time t2 is shown;

[0044] Step 5.2: Determine the corresponding metal ring number based on the amplitude difference of the multi-channel signal synchronous acquisition module data at the moment when the fluid is generally stable. When the oil-water interface is located between a certain group of metal rings, the signal of this group of metal rings is between the maximum and minimum values. When the oil-water interface is located between two adjacent groups of metal rings, the response signals of the metal rings above it are at the maximum value, and the signals of the metal rings below it are at the minimum value.

[0045] Step 5.3: Based on the metal ring number and the corresponding depth information of each coded metal ring in the conductivity array, determine the depth of the interface between the oil and water mixture. This position is the position of the oil-water interface after the fluid stabilizes.

[0046] Example 1:

[0047] In this embodiment, a three-phase bubbly flow of oil, gas, and water is generated, with N=16, i.e., 8 sets of metal rings. The 2N metal rings in the conductivity array 103 are numbered sequentially from top to bottom, with the topmost ring numbered as ring 1 and the bottommost as ring 32. Initially, the three-phase mixture of oil, gas, and water fills the interior of the protective shell 106 and the conductivity array 105, and there is no interface between the media. When the solenoid valve 201 is closed, the fluid stops flowing and stratification occurs due to gravity. After a period of time, the oil-gas interface 321 forms and stabilizes. At this time, the oil-water interface 322 has also formed, but the oil layer thickness is very thin and negligible. After another period of time, the oil-water interface 322 reaches a stable state. When the oil-gas interface is stable, it is located between the seventh and eighth metal rings, at which point the oil layer is very thin. When the oil-water interface is stable, it is located between the tenth and eleventh metal rings.

[0048] Detection principle: The control module 103 controls the multi-channel excitation module to generate excitation, which generates voltage in two adjacent metal rings. At the same time, the multi-channel signal synchronous acquisition module acquires this voltage. In a three-phase system of oil, gas, and water, the electrical conductivity of oil and gas is similar. However, in oil fields, water, due to dissolved impurities, has a significantly stronger electrical conductivity than oil and gas. This means the response signal between adjacent metal rings is related to the water content between the two rings. When there is no water or the water content between the two rings remains constant, the response signal will reach a stable state. The density difference between oil and gas is significantly greater than the density difference between oil and water. Furthermore, due to the higher viscosity of oil, when the solenoid valve is closed, the mixed fluid stops flowing, and the gas phase rapidly rises and forms a gas layer. The time required for the gas layer to stabilize is much shorter than the time required for the oil layer to stabilize; that is, when the gas layer stabilizes, only a very thin layer of oil or even no complete oil layer forms. After the gas layer stabilizes, the rate of change of the response signal between the metal rings in the oil-water mixture will significantly decrease. Therefore, the formation time of the oil-gas interface can be determined by the rate of change of the response signal between the metal rings, and the location of the oil-gas interface can be determined based on the number of metal rings in the conductivity array whose response signals have reached a stable state, starting from the first metal ring. Figure 3 As shown, at this time, the oil-gas interface 321 is formed between the seventh and eighth metal rings, i.e., within the fourth group. Therefore, the upper three groups, from the first to the sixth metal rings, are entirely filled with gas, resulting in maximum resistance and stable, maximum response signals for the metal rings. The fourth group of metal rings contains a mixture of gas, oil, and water, with resistance at an intermediate value. The amplitude of the response signal for the fourth group of metal rings is between its maximum and minimum values. In the fifth group of metal rings and below, the water and oil are still flowing, and the signal changes slowly. If the oil-gas interface 321 is formed between the eighth and ninth metal rings, i.e., between the fourth and fifth groups, then the response signals of the first to fourth groups of metal rings are stable and at their maximum values, while the response signals of the fifth group of metal rings and below change slowly.

[0049] For the oil-water interface, after final stabilization, there is a significant difference in resistance between the metal rings in the oil layer and those in the water layer. Specifically, when the oil-water interface 322 stabilizes between the tenth and eleventh metal rings (the ninth and tenth metal rings form one group, and the eleventh and twelfth metal rings form another group), i.e., between the fifth and sixth groups, the response signals of the first and fifth groups of metal rings are at their maximum values, while the response signals of the sixth group and below are at their minimum values. When the oil-water interface 322 stabilizes between the eleventh and twelfth metal rings, i.e., within the sixth group of metal rings, the signal amplitude of the sixth group of metal rings is between its maximum and minimum values. The amplitudes of the first to fifth groups of metal rings stabilize at their maximum values, while the amplitudes of the seventh group and below stabilize at their minimum values.

[0050] Once the interface is determined to be located at the metal ring position, the depth information of each interface can be obtained by combining the metal ring number with the depth information of the corresponding position of each coded metal ring in the conductivity array.

[0051] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A detection system for the interface between oil, gas, and water media, comprising a detection module (202), wherein a solenoid valve (201) is provided at the top of the detection module (202) and a one-way valve (203) is provided at the bottom, characterized in that: The detection module (202) includes a conductivity array (105), which is connected to a multi-channel excitation module (101) and a multi-channel signal synchronous acquisition module (103). The multi-channel excitation module (101) and the multi-channel signal synchronous acquisition module (103) are connected to the control module (102). The conductivity array (105) includes an installation pipe and multiple embedded metal rings whose center points are on the same straight line and are equidistantly arranged along the pipe direction. A pressure-resistant protective shell (106) is provided outside the installation pipe. The pressure-resistant protective shell (106) is injection molded and is completely fitted to the installation pipe of the conductivity array (105). The number of embedded metal rings is 2N. The multi-channel excitation module (101) includes N independent excitation output channels with positive terminals and 1 output negative terminal shared by all channels. All channels can output excitation synchronously. The multi-channel signal synchronous acquisition module (103) includes N independent input channels that can be synchronously converted, and thus can synchronously acquire signals from all input channels. The metal rings are numbered sequentially from top to bottom, with each group consisting of two metal rings. In each group, the metal rings with odd numbers are connected to both the positive terminal of the corresponding excitation output channel of the multi-channel excitation module (101) and the corresponding input channel of the multi-channel signal synchronous acquisition module (103). The metal rings with even numbers are only connected to the negative terminal of the multi-channel excitation module (101). The multi-channel excitation module (101), the multi-channel signal synchronous acquisition module (103), and the control module (102) are all located in the control box (104).

2. A method for detecting the interface between oil, gas, and water media, implemented using the detection system described in claim 1, comprising the following steps: Step 1: Open the check valve and solenoid valve. In the initial state, the three-phase fluid of oil, gas and water flows into and fills the conductive array. Step 2: Close the solenoid valve. The three-phase fluid of oil, gas and water in the conductivity array stops flowing, and the oil, gas and water move freely under the influence of gravity. Step 3: Synchronously excite all metal rings using a multi-channel excitation module and synchronously acquire the response signals of all metal rings using a multi-channel signal synchronous acquisition module; Step 4: Determine the location of the oil-gas interface based on the switching speed of different channels of the multi-channel signal synchronous acquisition module. Step 4 is detailed below: Step 4.1: Determine the formation time of the interface between the gas phase and the oil-water mixture after the solenoid valve is closed based on the jump speed of the output data of the multi-channel signal synchronous acquisition module; Step 4.2: Based on the determined formation time of the interface between the gas phase and the oil-water mixture, calculate the number of conduction ring groups where the signal is in a stable state. When the oil-gas interface is located between a certain group of metal rings, the signal of this group of metal rings is stable and the amplitude is between the maximum and minimum values. The signals of the metal rings above it are stable and at the maximum value, while the signals of the lower groups are in a slow changing state or stable at the minimum value. When the oil-gas interface is located between two adjacent groups of metal rings, the response signals of the metal rings above it are stable and at the maximum value, while the signals of the lower groups are in a slow changing state or stable at the minimum value. Step 4.3: Based on the number of the metal rings and the depth information of the corresponding positions of each coded metal ring in the conductivity array, determine the position and depth of the interface between the gas phase and the oil-water mixture. This position is the position of the oil-gas interface after the fluid stabilizes. Step 5: Determine the location of the oil-water interface based on the stable amplitude of the output data from the multi-channel signal synchronous acquisition module; Step 5 is detailed below: Step 5.1: Determine the moment when the fluid stabilizes after the solenoid valve is closed based on the stabilization time of the data from the multi-channel signal synchronous acquisition module; Step 5.2: Determine the corresponding metal ring number based on the amplitude difference of the multi-channel signal synchronous acquisition module data at the moment when the fluid is generally stable. When the oil-water interface is located between a certain group of metal rings, the signal of this group of metal rings is between the maximum and minimum values. When the oil-water interface is located between two adjacent groups of metal rings, the response signals of the metal rings above it are at the maximum value, and the signals of the metal rings below it are at the minimum value. Step 5.3: Based on the metal ring number and the corresponding depth information of each coded metal ring in the conductivity array, determine the depth of the interface between the oil and water mixture. This position is the location of the oil-water interface after the fluid stabilizes.

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