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Method for improving crude oil recovery ratio by using guanidine gum fracturing backflow liquid

A fracturing flowback fluid and recovery factor technology, which is applied in the fields of production fluids, earthwork drilling, wellbore/well components, etc., can solve problems such as affecting crude oil dehydration, waste of resources, and complex processing processes, and achieve resource utilization. The effect of utilization, reduction of construction costs, and convenient operation and management

Active Publication Date: 2015-12-16
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
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AI Technical Summary

Problems solved by technology

There are currently some problems in the three processing methods: (1) It is difficult and costly to meet the standards for efflux
Due to the complex composition of the fracturing flowback fluid, the COD is as high as tens of thousands or even hundreds of thousands of mg / L, while the discharge environment requires that the COD is usually lower than 60 mg / L, resulting in complicated treatment processes and a cost of up to 200 yuan / m3; (2) Reinjection Treatment Affects the Stable Operation of Water Injection System
The reinjection treatment of fracturing flowback fluid is usually to oxidize and break the fracturing flowback fluid, and then enter the combined station for treatment together with the oil production sewage. Since the flowback fluid still contains a large amount of polymer substances, it will not only affect the efficiency of the combined station The dehydration of crude oil will also increase the load of the filtration process, and the sudden increase in the amount of external water delivery will also affect the effect of water injection development in the block; (3) The main purpose of reuse treatment is to purify the flowback liquid for use in Re-preparation of fracturing fluid is an ideal way to dispose of fracturing flowback fluid, but most of them are currently in the experimental stage
[0004] The reuse treatment method for the purpose of re-preparing fracturing fluid mainly adopts oil removal, chemical oxidation, flocculation, filtration, etc., which not only remove crude oil, suspended impurities, scaling ions, etc. in the flowback fluid, but also Residual organic substances such as guar gum are removed, resulting in a waste of resources

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] The guar gum fracturing flowback fluid of well A in a certain block of Shengli Oilfield has a pH of 9.5, a median particle size of suspended solids of 120 μm, and a mass concentration of guar gum of 0.6%. There are 25 oil wells in a block H of Shengli Oilfield, the reservoir temperature is 52°C, the salinity is 9862mg / L, and the recoverable reserves are 2.5×10 5 t, pore volume 3.6×10 4 m 3 , with a water content of 92.3%, and a recovery rate of 35.2%. Utilize the method of the present invention to use the guar gum class fracturing flowback fluid of block A oil well to improve the crude oil recovery of certain block H in Shengli Oilfield, and concrete steps are as follows:

[0022] (1) Adjusting the pH of the fracturing flowback fluid to 7.0 eliminates the harmful effect of the alkaline environment on the reservoir microorganisms.

[0023] (2) The guar gum fracturing flowback fluid is coarsely filtered through quartz sand to remove suspended impurities with a particle...

Embodiment 2

[0029] The pH of guar gum fracturing flowback fluid in well D in a certain block of Shengli Oilfield is 10.2, the median particle size of suspended solids is 115 μm, and the mass concentration of guar gum is 0.8%. There are 21 oil wells in a block F of Shengli Oilfield, the reservoir temperature is 65°C, the salinity is 12536mg / L, and the recoverable reserves are 4.3×10 5 t, pore volume 5.9×10 4 m 3 , with a water content of 95.1%, and a recovery rate of 32.3%. Utilize the method of the present invention to use the guar gum type fracturing flowback liquid of block D oil well to improve the crude oil recovery of certain block F in Shengli Oilfield, and concrete steps are as follows:

[0030] (1) Adjusting the pH of the fracturing flowback fluid to 6.5 eliminates the harmful effect of the alkaline environment on the reservoir microorganisms.

[0031] (2) The guar gum fracturing flowback fluid is coarsely filtered through quartz sand to remove suspended impurities with a parti...

Embodiment 3

[0037]The guar gum fracturing flowback fluid of well G in a certain block of Shengli Oilfield has a pH of 6.2, a median particle size of suspended solids of 132 μm, and a mass concentration of guar gum of 0.9%. There are 18 oil wells in a block M of Shengli Oilfield, the reservoir temperature is 70°C, the salinity is 7896mg / L, and the recoverable reserves are 7.2×10 5 t, pore volume 6.6×10 4 m 3 , with a water content of 91.0%, and a recovery rate of 37.5%. Utilize the method of the present invention to use the guar gum type fracturing flowback fluid of the block G oil well to improve the oil recovery of a certain block M in Shengli Oilfield, and the concrete steps are as follows:

[0038] (1) Adjust the pH of the fracturing flowback fluid to 7.5 to eliminate the harmful effect of the alkaline environment on the reservoir microorganisms.

[0039] (2) The guar gum fracturing flowback fluid is coarsely filtered through quartz sand to remove suspended impurities with a particl...

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Abstract

The invention belongs to the technical field of tertiary oil recovery, and in particular, relates to a method for improving a crude oil recovery ratio by using guanidine gum fracturing backflow liquid. The method specifically comprises the following steps that pH of the fracturing backflow liquid is adjusted to 6.5-7.5; then, suspension impurities with particle sizes not less than 50 microns are removed through two-grade filtration; the content of guanidine gum in the fracturing backflow liquid is adjusted to reach the mass concentration of 1.0-1.5%; a nitrogen source and a phosphorus source are synchronously added; the mass concentrations of the nitrogen source and the phosphorus source are respectively 0.2-0.5% and 0.1-0.3% after adding; the fracturing backflow liquid added with the nitrogen source and the phosphorous source is injected in an oil reservoir from a water injection well; and injection allocation of air is performed. The method has the characteristics of simple flows, mature processing unit process, stable whole process and low cost, can realize the reinjection of the fracturing backflow liquid into the oil reservoir, realizes the resource utilization of sewage, and can be widely applied to field tests of improving the crude oil recovery ratio by microorganisms.

Description

technical field [0001] The invention belongs to the technical field of tertiary oil recovery, and in particular relates to a method for improving oil recovery by using guar gum type fracturing flowback fluid. Background technique [0002] At present, unconventional oil and gas reservoirs such as tight oil and gas are being vigorously developed, and large-scale hydraulic fracturing is the main development method. Large-scale hydraulic fracturing will produce a large amount of flowback fluid, and the flowback fluid volume of a single unconventional well can reach more than 2,000 cubic meters. More than 90% of the currently used fracturing fluid system is guar gum fracturing fluid. The flowback fluid not only contains a large amount of crude oil and suspended impurities, but also contains a large amount of guar gum residual liquid. The composition is complex, the COD is high, and the treatment is difficult. Important issues affecting the development of unconventional oil and g...

Claims

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Application Information

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IPC IPC(8): E21B43/26E21B43/22
Inventor 汪卫东袁长忠潘永强徐鹏徐闯巴燕段传慧吴晓玲冯云王静
Owner CHINA PETROLEUM & CHEM CORP
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