Carbonate reservoir geology-engineering integrated water plugging method

Abstract

The application discloses a carbonate rock oil reservoir geology-engineering integrated water plugging method, which comprises the following steps: (1) finely depicting the oil reservoir; (2) integrated design of the water plugging method and accurate control of field construction, etc. The application changes the water control idea, strengthens the integration of geology and engineering in key links such as potential evaluation, fracture-vug depiction, oil-water occurrence, plugging agent selection, process design, dynamic adjustment and effect evaluation, realizes the organic integration of the oil reservoir description and engineering matching, improves the success rate of the water plugging process of the carbonate rock oil reservoir, and realizes the economy and sustainability of water plugging.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil exploitation, in particular to a carbonate rock oil reservoir geological engineering integrated water plugging method. BACKGROUND

[0002] In the process of exploiting oil through oil wells, as the degree of oil recovery continues to improve, the amount of remaining oil in the oil layer continues to decrease, and the distribution of oil gradually becomes scattered, so the requirement for improving oil recovery is increasing. Due to the increasing depth of exploitation and the damage of casing, water in the water layer is injected into the water well, and the distribution of oil in the oil layer is scattered, so the utilization rate of water injection is low, which further leads to water flooding in the oil well. Water plugging of the oil well can improve the oil production of the oil well.

[0003] CN112814618A discloses a selective chemical water plugging method, which comprises: providing a temporary plugging agent and a water plugging agent; injecting the temporary plugging agent into the oil casing annulus of the oil well; after a first waiting time, the temporary plugging agent solidifies and coagulates; during the solidification period of the temporary plugging agent, the water plugging agent is injected into the oil casing annulus; the oil well is shut in; after a second waiting time, the water plugging agent solidifies and coagulates. Since the method protects the oil layer with the temporary plugging agent before injecting the water plugging agent into the oil casing annulus, and since the temporary plugging agent can degrade within a certain time after entering the oil layer, the permeability of the oil layer is restored, so the method can effectively and selectively plug the water of the oil well, simplify the water plugging operation process, save cost, improve the water plugging operation efficiency, and ensure the water plugging effect.

[0004] CN112360368A discloses an oil well water plugging method, which can determine the sealing condition of the oil well by well killing, well cleaning and scraping, setting and verifying the casing, etc. during the process of plugging the oil well, and complete the water plugging of the oil well by injecting cement mortar and sand, injecting plugging agent, etc. After the water plugging is completed, the oil well production is restored. The process of plugging the oil well is simple, the water plugging efficiency is high, the success rate of plugging the oil well is improved, the water content in the oil well is reduced, and the output of the oil well is improved.

[0005] With the gradual development of carbonate rock oil field development, the bottom water rises year by year, the remaining oil distribution is complex, and the water control and potential tapping difficulty is increasing. At present, the number of low-efficiency wells caused by bottom water rising increases year by year, the conventional water plugging method in the early stage is not high in efficiency, the bottom water reservoir water control is difficult, the effect is poor, and it is urgent to find an efficient carbonate rock oil reservoir water plugging technology method. SUMMARY

[0006] In order to solve the above technical problems, the present application provides a carbonate reservoir geological engineering integrated water plugging method, which realizes organic integration of reservoir description and engineering matching, and improves the success rate of carbonate reservoir water plugging technology.

[0007] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0008] A carbonate reservoir geological engineering integrated water plugging method, comprising the following steps:

[0009] (1) Determine the fracture and cave distribution and fracture size through seismic data, drilling and logging data and completion data, and finely build a fracture and cave model; then use the static carving and material balance method, and use the dynamic and static combination method to calculate the oil well reserve size and evaluate the oil well water plugging potential;

[0010] (2) According to the evaluation index of the oil well water plugging potential obtained in step (1), match the plugging agent system combined with the reservoir demand, and determine the dosage of the plugging agent system according to the acid fracturing curve and the energy indication curve;

[0011] (3) According to the oil well water plugging potential index obtained in step (1) and the plugging agent system and its dosage obtained in step (2), guide the construction dynamic adjustment and optimize the construction parameters.

[0012] Preferably, the index for evaluating the oil well water plugging potential in step (1) includes: water body invasion path, number of formation channels, water body energy and oil-water channel position.

[0013] Further preferably, the water body invasion path is determined according to the oil well production performance, the water breakthrough sequence of each oil well in the region and the oil and gas filling path, and is used to guide the engineering plugging direction.

[0014] Further preferably, the number of formation channels is obtained according to the oil well acid fracturing curve and the water content rising characteristics, and is used to guide the dosage of the plugging agent.

[0015] Further preferably, the water body energy is obtained according to the energy indication curve and the water invasion amount curve, and is used to guide the plugging strength.

[0016] Further preferably, the oil-water channel position is determined according to the data of the emptying and leakage layer position, the water injection profile test and the logging data, and is used to guide the engineering plugging position.

[0017] Preferably, the matching method of the plugging agent system in step (2) is: when the near well is a fractured reservoir, a colloidal organic plugging agent is used as the plugging agent system to maintain the channel foundation; when the near well is a solution cave reservoir, a granular plugging agent and a colloidal plugging agent are used as the plugging agent system.

[0018] Preferably, the method for determining the amount of the plugging agent system in step (2) is specifically: according to the acid fracturing curve, the cumulative injection amount when the acid fracturing is communicated is approximately considered as the effective volume of the fracture channel around the well; according to the energy indication curve, the cumulative liquid production amount in the K1 stage is approximately considered as the effective volume of the fracture network around the well.

[0019] Preferably, the construction parameters in step (3) include injection pressure, displacement and displacement amount.

[0020] The application further provides application of the carbonate reservoir geology-engineering integrated water plugging method in water plugging engineering of the carbonate reservoir.

[0021] The application has the following beneficial effects:

[0022] The application changes the water control idea, strengthens the integration of geology and engineering in key links such as potential evaluation, fracture and cave description, oil and water occurrence, plugging agent selection, process design, dynamic adjustment and effect evaluation, realizes the organic integration of reservoir description and engineering matching, improves the success rate of the water plugging process of the carbonate reservoir, and realizes the economy and sustainability of water plugging. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is an acid fracturing indication curve.

[0024] Figure 2 It is an energy indication curve. DETAILED DESCRIPTION

[0025] The embodiments of the application are described below by way of specific examples, and those skilled in the art can easily understand other advantages and effects of the application from the disclosure. The application can also be implemented or applied by different specific embodiments, and the details in the specification can be modified or changed based on different views and applications without departing from the spirit of the application.

[0026] Before further describing the specific embodiments of the application, it should be understood that the protection scope of the application is not limited to the following specific embodiments; it should also be understood that the terms used in the embodiments of the application are used for describing the specific embodiments, but not for limiting the protection scope of the application.

[0027] A carbonate reservoir geology-engineering integrated water plugging method comprises the following steps:

[0028] (1) finely describe the reservoir

[0029] Determine the fracture and cave distribution and fracture size through seismic data, drilling and logging data and completion data, finely build a fracture and cave model, and then calculate the oil well reserve size and evaluate the oil well water plugging potential by using the static carving and material balance method and the dynamic and static combination method.

[0030] (2) Water plugging method integrated design

[0031] According to the evaluation index of the oil well water plugging potential obtained in step (1), the plugging agent system is matched in combination with the reservoir demand, and the amount of the plugging agent system is determined according to the acid fracturing curve and the energy indication curve.

[0032] (3) Field construction precise control

[0033] According to the oil well water plugging potential index obtained in step (1) and the plugging agent system and the amount thereof obtained in step (2), the construction dynamic adjustment is guided, and the construction parameters are optimized.

[0034] Preferably, the index for evaluating the oil well water plugging potential in step (1) comprises a water body invasion path, a number of formation channels, water body energy and an oil-water channel position.

[0035] Further preferably, the water body invasion path is determined according to the oil well production dynamic, the water breakthrough sequence of each oil well in the region and the oil and gas filling path, and is used for guiding the engineering plugging direction.

[0036] Further preferably, the number of formation channels is obtained according to the acid fracturing curve and the water content rising characteristics, and is used for guiding the amount of the plugging agent.

[0037] Further preferably, the water body energy is obtained according to the energy indication curve and the water invasion amount curve, and is used for guiding the plugging strength.

[0038] Further preferably, the oil-water channel position is determined according to the data of the emptying loss layer position, the water injection profile test and the logging data, and is used for guiding the engineering plugging position.

[0039] Preferably, the matching method of the plugging agent system in step (2) is that when the near-well is a fractured reservoir, a colloidal organic plugging agent is used as the plugging agent system to maintain the channel foundation; and when the near-well is a solution cavity reservoir, a granular plugging agent and a colloidal plugging agent are used as the plugging agent system.

[0040] Preferably, the determination method of the amount of the plugging agent system in step (2) is that according to the acid fracturing curve, the cumulative injection amount when the acid fracturing is communicated is approximately considered as the effective volume of the fracture channel around the well; and according to the energy indication curve, the cumulative liquid production amount in the K1 stage is approximately considered as the effective volume of the fracture network around the well.

[0041] Preferably, the construction parameters in step (3) comprise injection pressure, displacement and displacement amount.

[0042] The application also provides application of the above-mentioned carbonate rock oil reservoir geological engineering integrated water plugging method in the water plugging engineering of the carbonate rock oil reservoir.

[0043] Example 1

[0044] The comprehensive water content of Tahe Oilfield No. 3 Plant has been increasing year by year, and is currently 65.3%, among which the comprehensive water content of Tahe No. 8 area is 81.1%, and the comprehensive water content of Tuofutai area is 62.4%. The annual production decline caused by bottom water uplift accounts for more than 40% of the total decline. At present, the low-efficiency wells caused by bottom water uplift account for 22% of the number of production wells. The conventional water plugging method in the early stage is not high in efficiency. From 2015 to 2019, a total of 7 well times of water plugging operation were implemented, 2 well times were effective, the effective rate was 28.6%, the oil increment was 624 t, the conversion ton oil cost was 4865 yuan, the bottom water reservoir is difficult to control and treat water, and the effect is poor.

[0045] The present application provides a carbonate reservoir geological engineering integrated water plugging method, changes the water control idea, strengthens the integration of geology and engineering in key links such as potential evaluation, fracture and cave description, oil and water occurrence, plugging agent selection, process design, dynamic adjustment and effect evaluation, improves the pertinence, effectiveness and adaptability of water plugging process, and realizes the economy and sustainability of water plugging.

[0046] The carbonate reservoir geological engineering integrated water plugging method specifically includes the following steps:

[0047] (1) Fine description of reservoir

[0048] Through seismic data, drilling and logging data, and completion data, the fracture and cave distribution and fracture size are determined, and a fracture and cave model is finely constructed. Then, by using the static carving and material balance method, the oil well reserves scale is more accurately calculated by using the dynamic and static combination method, and the oil well water plugging potential is evaluated. ① According to the oil well production dynamic, the water breakthrough sequence of each oil well in the region, and the oil and gas filling path, the water body invasion path is determined to guide the engineering plugging direction; ② According to the acid fracturing curve and water content rising characteristics of the oil well, the number of formation channels is determined to guide the dosage of the plugging agent; ③ According to the energy indication curve and water invasion amount curve, the water body energy is determined to guide the plugging strength; ④ Through the data of emptying and loss layer position, production and water absorption profile test, and logging data, the position of the oil and water channel is determined.

[0049] (2) Integrated design of water plugging method

[0050] According to the reservoir demand, the plugging agent system and the dosage are matched. ① For the fracture reservoir near the well, a colloidal organic plugging agent is used to maintain the channel foundation; for the cave reservoir near the well, a “granular plugging agent + colloidal plugging agent” is used. ② The dosage is determined according to the acid fracturing curve: the cumulative injection amount when the acid pressure communicates is approximately considered as the effective volume of the fracture channel around the well; the dosage is determined according to the energy indication curve: the cumulative liquid production amount in K1 stage is approximately considered as the effective volume of the fracture network around the well. Figure 1 and 2 as shown.

[0051] (3) Precise control of field construction

[0052] Combined with key parameters such as well storage relationship, plugging position, and performance of plugging agent composition, the application guides dynamic adjustment of construction, optimizes injection pressure, displacement, and displacement volume, reduces wellbore plugging risk, and improves water plugging success rate.

[0053] Implementation effect

[0054] In 2020, 24 well times of geological engineering integrated water plugging were implemented in carbonate reservoirs, of which 15 well times were effective, and 1.82 million tons of oil were increased in the whole year. Compared with the previous period, various indicators were greatly improved: the effective rate increased from 22% to 63%, the single well operation cost decreased from 810 million yuan to 46 million yuan, and the converted ton of oil cost decreased from 4556 yuan / ton to 638 yuan / ton.

[0055] Economic benefit analysis:

[0056] ① Input cost: 24 well times of geological engineering integrated water plugging, single cost 460 million yuan, cumulative investment 1104 million yuan.

[0057] ② Output benefit: After the promotion and application of the technology, 1.82 million tons of oil were increased, the crude oil price was 1700 yuan / ton, and the cumulative output benefit was 3094 million yuan.

[0058] ③ Net benefit: 3094-1104=1990 million yuan.

[0059] The application combines the geological characteristics of carbonate reservoirs, and matches targeted engineering technology, achieves outstanding results, opens up a new direction for water control and treatment technology of carbonate reservoirs, and can be popularized and applied in such reservoirs.

[0060] The above is a further description of the application combined with specific embodiments, but these embodiments are only exemplary and do not constitute any limitation on the scope of the application. Those skilled in the art should understand that the details and forms of the technical solutions of the application can be modified or replaced without departing from the spirit and scope of the application, and such modifications and replacements all fall within the protection scope of the application.

Claims

1. A method for integrated geological and engineering water shut-off in carbonate oil reservoirs, characterized in that, Includes the following steps: (1) Determine the distribution and scale of fractures and vulcanizations through seismic data, drilling and logging data and well completion data, and construct a detailed fracture and vulcanization model; then use static sculpting and material balance methods, and apply a combination of dynamic and static methods to calculate the oil well reserve scale and assess the oil well water shut-off potential. (2) Based on the evaluation index of the water shut-off potential of the oil well obtained in step (1), and in combination with the reservoir requirements, match the plugging agent system, and determine the amount of plugging agent system based on the acid pressure curve and energy indicator curve; (3) Based on the oil well water shut-off potential index obtained in step (1) and the plugging agent system and its dosage obtained in step (2), guide the dynamic adjustment of construction and optimize construction parameters; The indicators for assessing the water shut-off potential of oil wells mentioned in step (1) include: water invasion path, number of formation channels, water energy, and location of oil-water channels; The number of formation channels is obtained based on the well acid fracturing curve and water cut rise characteristics, and is used to guide the amount of plugging agent used. The water energy is obtained from the energy indicator curve and the water intrusion curve, and is used to guide the sealing intensity; The method for determining the amount of plugging agent system mentioned in step (2) is as follows: based on the acid fracturing curve, the cumulative injection volume during acid fracturing is approximately considered as the effective volume of the well perimeter fracture channel; based on the energy indicator curve, the cumulative production volume in stage K1 is approximately considered as the effective volume of the well perimeter fracture network. The K1 stage is the pressure release stage of the sewing mesh.

2. The integrated geological and engineering water shut-off method for carbonate reservoirs according to claim 1, characterized in that, The water intrusion path is determined based on the oil well production dynamics, the water breakthrough sequence of each oil well in the area, and the oil and gas charging path, and is used to guide the direction of engineering plugging.

3. The integrated geological and engineering water shut-off method for carbonate reservoirs according to claim 1, characterized in that, The location of the oil-water channel is determined based on data from the venting and leakage layers, water production profile tests, and well logging data, and is used to guide the location of the sealing operation.

4. The integrated geological and engineering water shut-off method for carbonate reservoirs according to claim 1, characterized in that, The matching method of the plugging agent system in step (2) is as follows: when the reservoir near the well is a fractured reservoir, a colloidal organic plugging agent is used as the plugging agent system to maintain the channel foundation; when the reservoir near the well is a cavernous reservoir, a combination of particulate plugging agent and colloidal plugging agent is used as the plugging agent system.

5. The integrated geological and engineering water shut-off method for carbonate reservoirs according to claim 1, characterized in that, The construction parameters mentioned in step (3) include injection pressure, discharge rate and displacement rate.

6. The application of the integrated geological and engineering water shut-off method for carbonate reservoirs according to any one of claims 1-5 in water shut-off engineering of carbonate reservoirs.

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