Double-slug compound profile control agent for fractured reservoir and use method of profile control agent

A profile control agent and oil reservoir technology, applied in chemical instruments and methods, earthwork drilling and production, production fluids, etc., can solve the problems that are difficult to meet the requirements of polymer flooding development of fractured reservoirs, affect the development effect of fractured reservoirs, molecular line Narrow cluster size distribution and other issues, to achieve the effects of inhibiting the formation of dead oil zones, reducing the critical micelle concentration, and enhancing adaptability

Inactive Publication Date: 2017-11-10
DALIAN DONGYOU RUIJIA PETROLEUM TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Moreover, due to the development of high-angle structural fractures and low-angle detachment fractures and diagenetic fractures in the reservoir, the water absorption capacity of the fractures becomes stronger during water injection, resulting in a decrease in the water absorption index of the reservoir.
[0005] 3. There are many dead oil areas. In the conventional water flooding process, most of the displacement fluid flows through the fracture system, resulting in uneven water absorption profiles. Dead oil areas are gradually formed in areas that have not been affected by the displacement fluid, seriously affecting fractures. Type reservoir development effect
[0006] 4. The currently used polymer is usually partially hydrolyzed polyacrylamide, which has poor salt resistance and narrow molecular coil size distribution, which is easy to be lost in the process of polymer flooding, and it is difficult to adapt to the development needs of polymer flooding in fractured reservoirs

Method used

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  • Double-slug compound profile control agent for fractured reservoir and use method of profile control agent
  • Double-slug compound profile control agent for fractured reservoir and use method of profile control agent
  • Double-slug compound profile control agent for fractured reservoir and use method of profile control agent

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] 1. The method of using the profile control agent: (1) First, carry out oxygen exposure treatment on the prepared water to reduce the dissolved oxygen content in the prepared water to below 3mg / L; (2) Add the agent to the prepared water at a constant speed at a temperature of 15°C. Stir for 4 hours to obtain the profile control agent; (3) After the preparation is completed, inject the profile control agent directly into the rock core.

[0037] 2. Prepare water, adjust the salinity to 500mg / L by adding NaCl to the distilled water, to simulate the source water used in oil field production.

[0038] 3. The specific application dosage is:

[0039] Slug A: The composite polymer is composed of three kinds of partially hydrolyzed polyacrylamide with different molecular weights, the molecular weights are 1200*10 4 、1900*10 4 、2500*10 4 , its mass ratio is 20:65:15; the mass ratio of complex polymer, chromium acetate, urotropine, sodium sulfite, O-benzyl-L-threonine benzyl oxa...

Embodiment 2

[0067] 1. The method of using the profile control agent: (1) First, carry out oxygen exposure treatment on the prepared water to reduce the dissolved oxygen content in the prepared water to below 3mg / L; (2) Add the agent to the prepared water at a constant speed at a temperature of 35°C. Stir for 5 hours to obtain the profile control agent; (3) After the preparation is completed, inject the profile control agent directly into the rock core.

[0068] 2. Prepare water, adjust the salinity to 8000mg / L by adding NaCl to the distilled water, to simulate the oil field sewage used in actual production.

[0069] 3. The specific application dosage is:

[0070] Slug A: The composite polymer is composed of three kinds of partially hydrolyzed polyacrylamide with different molecular weights, the molecular weights are 1200*10 4 、1900*10 4 、2500*10 4 , its mass ratio is 20:65:15; the mass ratio of compound polymer, chromium acetate, urotropine, sodium sulfite, nafuramide oxalate is 0.22%:...

Embodiment 3

[0098] 1. The method of using the profile control agent: (1) First, carry out oxygen exposure treatment on the prepared water to reduce the dissolved oxygen content in the prepared water to below 3mg / L; (2) Add the agent to the prepared water at a temperature of 55°C, Stir for 6 hours to obtain the profile control agent; (3) After the preparation is completed, inject the profile control agent directly into the rock core.

[0099] 2. To prepare water, adjust the degree of salinity by adding soluble salts to the distilled water, and the final degree of salinity is 35000mg / L, which is used to simulate the oilfield sewage used in actual production.

[0100] 3. The specific application dosage is:

[0101] Slug A: The composite polymer is composed of three kinds of partially hydrolyzed polyacrylamide with different molecular weights, the molecular weights are 1200*10 4 、1900*10 4 、2500*10 4 , its mass ratio is 20:65:15; the mass ratio of complex polymer, chromium acetate, urotrop...

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Abstract

A double-slug composite profile control agent for fractured reservoirs and its application method relate to the field of oilfield applied chemistry. The present invention injects into fractured oil reservoirs in the form of double slugs. The pre-slug mixes three kinds of partially hydrolyzed polyacrylamides with different molecular weights to form a composite polymer, and adds additives to the composite polymer to form a profile control agent, which can The high-permeability areas of fractured reservoirs are firmly blocked; the post-slug is a compound surfactant, which is injected into the reservoir after the front-slug is effectively blocked, and the surfactant is used for the medium-permeability and low-permeability areas of the reservoir. In order to reduce the remaining oil content in the reservoir and increase the water absorption index of the reservoir; improve the heterogeneity of the reservoir through the combination of double slugs, increase the follow-up water flooding sweep coefficient, and inhibit the formation of dead oil areas in fractured reservoirs to improve Traditional oil recovery methods have disadvantages such as low recovery rate and poor economic benefits for fractured reservoirs.

Description

technical field [0001] The invention relates to a double-slug composite profile control agent for fractured oil reservoirs and its application method. The profile control agent can improve the adaptability of reservoirs and further increase the oil recovery rate of fractured oil reservoirs, belonging to oilfield applied chemistry. drug field. Background technique [0002] In recent years, polymer flooding technology has been applied and tested on a large scale in Daqing, Shengli, Xinjiang and Bohai oilfields in China, and has achieved obvious effects of increasing oil production and reducing water loss, and the technical and economic effects are very significant. However, in the practice of polymer flooding, it is also found that for fractured reservoirs, the recovery degree is low, indicating that the efficiency of polymer application in fractured reservoirs is low; The impact of the system on reservoir development is multifold: [0003] 1. Fracture systems, especially st...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K8/506C09K8/512E21B33/13E21B43/22
CPCC09K8/506C09K8/512E21B33/13E21B43/16
Inventor 袁鹏飞张晓丽李新张志群宋鑫王磊马骁
Owner DALIAN DONGYOU RUIJIA PETROLEUM TECH CO LTD
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