Non-blowing horizontal well fluid production profile testing system

Abstract

The invention relates to the technical field of oil and gas field exploration and development, in particular to a non-flowing horizontal well fluid production profile testing system which comprises the following steps that S1, a horizontal well shaft is cleaned up; s2, preparing a photoelectric composite cable; s3, penetrating the first end of the photoelectric composite cable into the coiled tubing; s4, connecting the lower end of the coiled tubing with an outlet of the electric submersible pump, verifying whether the electric submersible pump is normal or not, and if not, stopping and starting to check the electric submersible pump; and if the photoelectric composite cable is normal, connecting the second end of the photoelectric composite cable with optical fiber monitoring equipment, checking whether the photoelectric composite cable is normal, and if the photoelectric composite cable is abnormal. The device is reasonable and compact in structure, the purpose of testing the liquid production profile of the non-flowing horizontal well is achieved, the problem of testing the liquid production profile of the non-flowing horizontal well with thick oil and poor wellbore conditions is solved, the liquid production contribution rate and the fracturing effect of each cluster of reservoirs are accurately known through accurate monitoring of the liquid production profile, and the fracturing efficiency is improved. And an important basis is provided for reservoir understanding and fracturing transformation scheme optimization.

Description

[0001] This invention relates to the field of oil and gas field exploration and development technology, and is a non-flowing horizontal well production profile testing system. Background Technology

[0002] In recent years, pilot tests for low-permeability shale oil and gas development have been conducted in domestic basins. These tests have confirmed that multi-stage, clustered volumetric fracturing in horizontal wells has become a key technology for improving efficiency and profitability. However, low-permeability reservoirs generally have complex lithology and strong heterogeneity, resulting in significant differences in production capacity after staged fracturing. To understand the production capacity effects of different stages and clusters under different fracturing techniques and to verify the classification of sweet spot reservoirs, it is urgent to conduct production profile tests on post-fracturing horizontal wells.

[0003] Currently, for self-flowing production conditions, horizontal well production profile monitoring technologies mainly include crawlers or coiled tubing connected to production profile instruments (equipped with turbine flow meters, temperature-pressure gauges, and fluid imaging instruments), monitoring with pre-installed production profile testing instruments in the horizontal section, and testing with fiber optic coiled tubing. For non-flowing production conditions, horizontal well production profile monitoring technology mainly includes testing processes such as ESP + logging instrument string and crawler + fiber optic composite cable, which are matched with coiled tubing. For example, Chinese patent document CN103075143A discloses a method for testing the production profile of a mechanically pumped horizontal well. This method involves connecting a long plunger hollow pump to the bottom of the tubing and lowering it to the designed pump depth of the horizontal well. The long plunger hollow pump seat is sealed inside the casing. The coiled tubing and logging cable are simultaneously lowered from the tubing to the lower part of the section to be tested for the production profile of the horizontal well. By pressurizing the coiled tubing on the ground, the release section is separated from the coiled tubing. The coiled tubing is then pulled out, and a reciprocating ground lifting device is connected to the upper end of the tubing to perform reciprocating pumping action. The production profile tester is then started. By slowly lifting the test cable, the production profile tester is moved upward to perform simultaneous production and testing operations.

[0004] Chinese patent document CN101403292A discloses a process method for testing the production profile of mechanically operated horizontal wells using the gas lift method. The method involves using a gas lift production string to lift the fluid profile, with a crawler connected to a production profile tester passing through the gas lift production string to the lower end of the test section. Nitrogen gas is then used to lift the fluid profile at the ground, and after stabilization, the cable is raised to perform the production profile test.

[0005] The article titled "Technology and Application of Production Profile Logging for Coiled Tube EV Submersible Pumps in Low-Liquidity Horizontal Wells" proposes a method that uses a cable for power supply within the coiled tubing, an EV submersible pump to increase wellbore flow, and a logging instrument for continuous monitoring. By dragging the tubing string, parameters such as flow rate, water cut, pressure, and temperature in the horizontal well section are continuously monitored, and the water-producing zones are determined. Key supporting equipment was developed, thus forming the production profile logging technology for coiled tubing EV submersible pumps in low-liquidity horizontal wells.

[0006] Currently, the testing method using an ESP + logging instrument string paired with coiled tubing suffers from poor stability during coiled tubing dragging. Formation sand production can easily cause the turbine probe to become stuck, and dragging can disrupt the flow of oil, gas, and water in the wellbore, affecting measurement accuracy. Testing using a crawler + fiber optic composite cable presents challenges for wells with long horizontal sections and viscous oil. Therefore, a non-flowing horizontal well production profile testing system is urgently needed to address the current testing difficulties, particularly for non-flowing wells with low pressure coefficients, prone to leakage, viscous oil, and sand production. Summary of the Invention

[0007] This invention provides a non-flowing horizontal well production profile testing system that overcomes the shortcomings of the prior art and can effectively solve the problems of low measurement accuracy and high measurement difficulty in the production profile testing of existing post-pressure horizontal wells.

[0008] The technical solution of this invention is achieved through the following measures: a non-flowing horizontal well production profile testing system, comprising the following steps:

[0009] S1, Clean the horizontal well shaft thoroughly;

[0010] S2, Prepare the fiber optic composite cable;

[0011] S3, insert the first end of the optical fiber composite cable into the continuous tubing;

[0012] S4. Connect the lower end of the coiled tubing to the outlet of the ESP to verify if the ESP is functioning properly. If not, stop and begin checking the ESP. If it is functioning properly, connect the second end of the photoelectric composite cable to the fiber optic monitoring equipment to check if the photoelectric composite cable is functioning properly. If the photoelectric composite cable is not functioning properly, stop and begin checking the photoelectric composite cable. If it is functioning properly, proceed to the next step.

[0013] S5, disconnect the second end of the optical fiber composite cable from the optical fiber monitoring equipment, and lower the electric submersible pump into the end of the horizontal well;

[0014] S6. Connect the second end of the photoelectric composite cable to the fiber optic acquisition device, start the electric submersible pump, and the fiber optic acquisition device collects data through the photoelectric composite cable. After the pump produces two wellbore volumes of liquid, turn off the electric submersible pump and shut down the well for more than 48 hours, and monitor the temperature recovery data of the horizontal section.

[0015] S7, restart the electric submersible pump to produce at the first output pump level, which is Q1. The fiber optic data acquisition device obtains the temperature data T of each cluster in the horizontal section during production via a photoelectric composite cable. i 开 Where i = 1, 2, 3...n, and n is the total number of fracturing clusters;

[0016] S8. Calculate the temperature difference between two adjacent clusters using the following formula.

[0017]

[0018] S9, ΔT i The quantity of ≥0.1℃ is m, if Then proceed to the next step; if Then, production is carried out using the second output pump, with the second output being Q2, and Q2 < Q1. Steps S7 and S8 are repeated until...

[0019] S10, Explanation and Analysis The output of a single cluster (segment) is obtained from the DTS / DAS data recorded by the production system at that time.

[0020] The following are further optimizations and / or improvements to the above-mentioned technical solution:

[0021] In step S2 above, the optical-electric composite cable contains four optical fibers and a multi-core cable, two of which are single-mode optical fibers and the other two are multi-mode optical fibers. The four optical fibers are used to collect temperature and sound data, and the multi-core cable is used to power the electric submersible pump. A heat insulation layer is provided between the multi-core cable and the four optical fibers.

[0022] In step S3 above, the length of the optoelectronic composite cable is greater than or equal to 1.1 times the length of the continuous tubing.

[0023] In step S4 above, the lower end of the coiled tubing is connected to the outlet of the electric submersible pump, the frequency converter is connected to the second end of the photoelectric composite cable, the input end of the frequency converter is connected to the power supply, and the electric submersible pump is verified to be normal through the frequency converter.

[0024] In step S4 above, the fiber optic monitoring device is an optical time domain reflectometer.

[0025] This invention has a reasonable and compact structure, which realizes the purpose of testing the production profile of non-flowing horizontal wells. It solves the problem of testing the production profile of non-flowing horizontal wells with thick oil and poor well conditions. Through precise monitoring of the production profile, the production contribution rate and fracturing effect of each reservoir cluster can be accurately understood, providing an important basis for reservoir understanding and optimization of fracturing and stimulation schemes.

[0026] This invention employs a continuous tubing with a photoelectric composite cable, connected at the end to an electric submersible pump (ESP), which is lowered to the bottom of the well. The photoelectric composite cable supplies power to the ESP to initiate production. Fiber optic DTS / DAS acquisition equipment collects and monitors data. Through fiber optic data interpretation, the production profile of non-flowing horizontal wells is evaluated, solving the problem of monitoring the production profile of non-flowing horizontal wells. This provides guidance for water exploration, reservoir evaluation, and fracturing effectiveness assessment. The monitoring process can meet the requirements of normal bottom-hole flow and is convenient to implement, especially for wells with intermittent oil and gas production, allowing for wellhead pressure testing. Detailed Implementation

[0027] The present invention is not limited to the following embodiments, and the specific implementation can be determined according to the technical solution of the present invention and the actual situation.

[0028] The present invention will be further described below with reference to embodiments:

[0029] Example 1: The non-flowing horizontal well production profile testing system includes the following steps:

[0030] S1, Clean the horizontal well shaft thoroughly;

[0031] S2, Prepare the fiber optic composite cable;

[0032] S3, insert the first end of the optical fiber composite cable into the continuous tubing;

[0033] S4. Connect the lower end of the coiled tubing to the outlet of the ESP to verify if the ESP is functioning properly. If not, stop and begin checking the ESP. If it is functioning properly, connect the second end of the photoelectric composite cable to the fiber optic monitoring equipment to check if the photoelectric composite cable is functioning properly. If the photoelectric composite cable is not functioning properly, stop and begin checking the photoelectric composite cable. If it is functioning properly, proceed to the next step.

[0034] S5, disconnect the second end of the optical fiber composite cable from the optical fiber monitoring equipment, and lower the electric submersible pump into the end of the horizontal well;

[0035] S6. Connect the second end of the photoelectric composite cable to the fiber optic acquisition device, start the electric submersible pump, and the fiber optic acquisition device collects data through the photoelectric composite cable. After the pump produces two wellbore volumes of liquid, turn off the electric submersible pump and shut down the well for more than 48 hours, and monitor the temperature recovery data of the horizontal section.

[0036] S7, restart the electric submersible pump to produce at the first output pump level, which is Q1. The fiber optic data acquisition device obtains the temperature data T of each cluster in the horizontal section during production via a photoelectric composite cable. i 开 , where i = 1, 2, 3...n, and n is the total number of fracturing clusters (n is a positive integer);

[0037] S8. Calculate the temperature difference between two adjacent clusters using the following formula.

[0038]

[0039] S9, ΔT i The quantity of ≥0.1℃ is m, if Then proceed to the next step; if This indicates that when producing with the first output pump, due to the excessive flow rate, the temperature data monitored by the photoelectric composite cable is mainly affected by the fluid temperature inside the coiled tubing. Therefore, production is switched to the second output pump, with a second output of Q2, where Q2 < Q1. Steps S7 and S8 are repeated until...

[0040] S10, Explanation and Analysis The output of a single cluster (segment) is obtained from the DTS / DAS data recorded by the production system at that time.

[0041] This invention achieves the purpose of testing the production profile of non-flowing horizontal wells, and solves the problem of testing the production profile of non-flowing horizontal wells with thick oil and poor well conditions. Through precise monitoring of the production profile, the contribution rate of production and fracturing effect of each reservoir cluster can be accurately understood, providing an important basis for reservoir understanding and optimization of fracturing and stimulation schemes.

[0042] This invention employs a continuous tubing with a photoelectric composite cable, connected at the end to an electric submersible pump (ESP), which is lowered to the bottom of the well. The photoelectric composite cable supplies power to the ESP to initiate production. Fiber optic DTS / DAS acquisition equipment collects and monitors data. By interpreting the collected data, the production profile of non-flowing horizontal wells can be evaluated, solving the problem of monitoring the production profile of non-flowing horizontal wells. This provides guidance for water exploration, reservoir evaluation, and fracturing effectiveness assessment. The monitoring process can meet the requirements of normal bottom-hole flow and is convenient to implement, especially for wells with intermittent oil and gas production, allowing for wellhead pressure testing.

[0043] The above-mentioned non-flowing horizontal well production profile testing system can be further optimized and / or improved according to actual needs:

[0044] Example 2: As an optimization of the above example, in step S2, the optoelectronic composite cable incorporates four optical fibers and a multi-core cable, two of which are single-mode fibers and the other two are multi-mode fibers. The four optical fibers are used to collect temperature and sound data, and the multi-core cable is used to power the electric submersible pump. A heat insulation layer is provided between the multi-core cable and the four optical fibers. The single-mode fiber is a known distributed optical fiber temperature sensing system (DTS), and the multi-mode fiber is a known distributed optical fiber acoustic sensing system (DAS). The four optical fibers are used to collect temperature and sound data, i.e., for DTS / DAS testing. The heat insulation layer between the multi-core cable and the four optical fibers prevents the heat generated by the multi-core cable during power supply from affecting the collected temperature data, thus improving the accuracy of the collected data.

[0045] Example 3: As an optimization of the above example, in step S3, the length of the optoelectronic composite cable is greater than or equal to 1.1 times the length of the continuous tubing. Having the optoelectronic composite cable greater than or equal to 1.1 times the length of the continuous tubing can prevent it from breaking under tension within the continuous tubing, ensuring its normal operation.

[0046] Example 4: As an optimization of the above example, in step S4, the lower end of the coiled tubing is connected to the outlet of the electric submersible pump (ESP), the frequency converter is connected to the second end of the photoelectric composite cable, and the input end of the frequency converter is connected to the power supply. The frequency converter is used to verify whether the ESP is functioning properly. By using the frequency converter to verify whether the ESP operates normally at multiple frequencies, it is possible to ensure the normal operation of the ESP when adjusting its operating frequency according to different production volumes, thus enabling normal production according to the production plan.

[0047] Example 5: As an optimization of the above example, in step S4, the fiber optic monitoring device is an optical time domain reflectometer (OTDR). An OTDR analyzes measurement curves to understand several properties of the optical fiber, such as uniformity, defects, breaks, and splice coupling. It is based on the principles of backscattering and Fresnel reflection of light, using the backscattered light generated when light propagates in the fiber to obtain attenuation information. It can be used to measure fiber attenuation, splice loss, locate fiber fault points, and understand the loss distribution along the fiber's length. This ensures the fiber optic composite cable is functioning properly before being lowered into the well, preventing faults from being brought down into the well, extending operation time, and improving work efficiency.

[0048] The working process of the preferred embodiment of the present invention:

[0049] The first step involved a multi-stage fractured horizontal well, H06, in the oilfield area. The horizontal section is 1,800 meters long, and the artificial bottom is 5,400 meters deep. A total of 128 fracturing clusters were perforated in this well. Currently, the well is in production with mechanical pumping. The tubing string inside the well has been removed, and the wellbore has been cleaned.

[0050] The second step is to prepare 6700 meters of optical fiber composite cable, which contains 4 optical fibers (2 single-mode and 2 multi-mode) for DTS / DAS testing. At the same time, the optical fiber composite cable contains a three-core power cable to supply power to the downhole electric submersible pump.

[0051] The third step is to insert the photoelectric composite cable into a continuous oil pipe with an outer diameter of Φ73mm and a length of 6000 meters, leaving a 10% margin for the photoelectric composite cable in the continuous oil pipe.

[0052] The fourth step is to connect the ESP (Electric Submersible Pump) to the end of the coiled tubing. Before entering the well, power the ESP by connecting the power cable through the frequency converter and verify that it is normal. Connect the optical fiber through the optical fiber monitoring device (OTDR) and monitor that the optical fiber is normal.

[0053] The fifth step is to run in the continuous tubing with the photoelectric composite cable, with the electric submersible pump at the bottom, and then run the electric submersible pump to the end of the horizontal well.

[0054] The sixth step is to supply power to the electric submersible pump via a power cable connected to a frequency converter, and to collect data using a fiber optic DTS / DAS acquisition device. After the pump produces enough fluid to fill two wellbore volumes (120 cubic meters), the well is shut in for more than 48 hours to monitor the temperature recovery data of the horizontal section.

[0055] Step 7: Power is supplied to the ESP (Electric Submersible Pump) to produce fluid at the initial output rate (Q1 = 30 cubic meters). The fluid flows upward through the ESP and along the coiled tubing. The fiber optic DTS / DAS acquisition equipment collects data to obtain the temperature data T of each cluster in the horizontal section during production. i 开 , i=1, 2, 3...n, n=128;

[0056] Step 8: Calculate the temperature difference between two adjacent clusters:

[0057]

[0058] Step 9: Calculate ΔT i The quantity m ≥ 0.1℃, where m = 90, then This indicates that when producing at the first output level (Q1 = 30 cubic meters), due to the excessive flow rate, the temperature data monitored by the photoelectric composite cable is mainly affected by the fluid temperature inside the coiled tubing. Therefore, production is reduced to the second output level (Q2 = 20 cubic meters), and steps seven and eight are repeated to calculate ΔT. i The quantity m ≥ 0.1℃, where m = 107, then

[0059] Step 10: Interpret and analyze the fiber DTS / DAS data recorded for the production system of the second output (Q2 = 20 cubic meters) to obtain the output of a single cluster (segment).

[0060] This invention has been applied and verified in multiple blocks of oilfields such as Xinjiang, enabling an accurate understanding of the production contribution rate of each cluster in non-flowing wells, which is of great significance for reservoir understanding and fracturing scheme optimization.

[0061] The above technical features constitute various embodiments of the present invention, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.

Claims

1. A non-flowing horizontal well production profile testing system, characterized in that... Includes the following steps: S1, Clean the horizontal well shaft thoroughly; S2, Prepare the fiber optic composite cable; S3, insert the first end of the optical fiber composite cable into the continuous tubing; S4. Connect the lower end of the coiled tubing to the outlet of the ESP to verify if the ESP is functioning properly. If not, stop and begin checking the ESP. If it is functioning properly, connect the second end of the photoelectric composite cable to the fiber optic monitoring equipment to check if the photoelectric composite cable is functioning properly. If the photoelectric composite cable is not functioning properly, stop and begin checking the photoelectric composite cable. If it is functioning properly, proceed to the next step. S5, disconnect the second end of the optical fiber composite cable from the optical fiber monitoring equipment, and lower the electric submersible pump into the end of the horizontal well; S6. Connect the second end of the photoelectric composite cable to the fiber optic acquisition device, start the electric submersible pump, and the fiber optic acquisition device collects data through the photoelectric composite cable. After the pump produces two wellbore volumes of liquid, turn off the electric submersible pump and shut down the well for more than 48 hours, and monitor the temperature recovery data of the horizontal section. S7, restart the electric submersible pump to produce at the first output pump level, which is Q1. The fiber optic data acquisition device obtains the temperature data T of each cluster in the horizontal section during production via a photoelectric composite cable. i 开 Where i = 1, 2, 3...n, and n is the total number of fracturing clusters; S8. Calculate the temperature difference between two adjacent clusters using the following formula. S9, ΔT i The quantity of ≥0.1℃ is m, if Then proceed to the next step; if Then, production is carried out using the second output pump, with the second output being Q2, and Q2 < Q1. Steps S7 and S8 are repeated until... S10, Explanation and Analysis The output of a single cluster (segment) is obtained from the DTS / DAS data recorded by the production system at that time.

2. The non-flowing horizontal well production profile testing system according to claim 1, characterized in that... In step S2, the optical-electric composite cable contains four optical fibers and a multi-core cable, two of which are single-mode optical fibers and the other two are multi-mode optical fibers. The four optical fibers are used to collect temperature and sound data, and the multi-core cable is used to power the electric submersible pump. A heat insulation layer is provided between the multi-core cable and the four optical fibers.

3. The non-flowing horizontal well production profile testing system according to claim 1 or 2, characterized in that... In step S3, the length of the photoelectric composite cable is greater than or equal to 1.1 times the length of the continuous tubing.

4. The non-flowing horizontal well production profile testing system according to claim 1 or 2, characterized in that... In step S4, the lower end of the coiled tubing is connected to the outlet of the electric submersible pump, the frequency converter is connected to the second end of the photoelectric composite cable, the input end of the frequency converter is connected to the power supply, and the electric submersible pump is verified to be normal through the frequency converter.

5. The non-flowing horizontal well production profile testing system according to claim 3, characterized in that... In step S4, the lower end of the coiled tubing is connected to the outlet of the electric submersible pump, the frequency converter is connected to the second end of the photoelectric composite cable, the input end of the frequency converter is connected to the power supply, and the electric submersible pump is verified to be normal through the frequency converter.

6. The non-flowing horizontal well production profile testing system according to claim 1, 2, or 5, characterized in that... In step S4, the fiber optic monitoring device is an optical time domain reflectometer.

7. The non-flowing horizontal well production profile testing system according to claim 3, characterized in that... In step S4, the fiber optic monitoring device is an optical time domain reflectometer.

8. The non-flowing horizontal well production profile testing system according to claim 4, characterized in that... In step S4, the fiber optic monitoring device is an optical time domain reflectometer.

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