CO2-injection asynchronous-throughput energy supplement method of ultralow-permeability compact oil reservoir horizontal wells

A technology for tight oil reservoirs and energy supplementation. It is used in earth-moving drilling, wellbore/well components, and production fluids. It can solve the problems of easy gas channeling, difficulty in improving ultimate recovery, and low sweep efficiency, and achieve improved permeability. rate, easy to scale up, and simple to implement

Active Publication Date: 2019-01-15
PETROCHINA CO LTD
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Problems solved by technology

[0006] Gas injection development based on unconventional reservoirs involves low sweep efficiency, easy gas channeling and difficulty in improving ultimate recovery. The purpose

Method used

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  • CO2-injection asynchronous-throughput energy supplement method of ultralow-permeability compact oil reservoir horizontal wells
  • CO2-injection asynchronous-throughput energy supplement method of ultralow-permeability compact oil reservoir horizontal wells
  • CO2-injection asynchronous-throughput energy supplement method of ultralow-permeability compact oil reservoir horizontal wells

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[0036] Example

[0037] This implementation provides a horizontal well CO injection for ultra-low permeability tight oil reservoirs 2 The method of asynchronous stimulation to supplement energy is to choose a horizontal well depletion development zone in Changqing Oilfield. This area is one of the tight oil test areas of Changqing Oilfield. The tight oil reservoir is Chang7 layer, and the buried depth is 2190-2570m. The average porosity of the layer is 7%-9%, the average permeability is 0.1-0.2mD, the original formation pressure is 15.8MPa, the viscosity of the formation crude oil is 1.23mPa·s, and the density is 0.74g / cm 3 , The gas-oil ratio is 75.40m 3 / t, saturation pressure 7.04MPa, the method specifically includes the following steps:

[0038] Step 1: Layout horizontal well row along the direction of maximum principal stress, such as figure 1 The shown layout diagram of the well row includes one local well and two adjacent wells, the well spacing is 400m, the horizontal well l...

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Abstract

The invention provides a CO2-injection asynchronous-throughput energy supplement method of ultralow-permeability compact oil reservoir horizontal wells. The method comprises that a horizontal well rowis arranged along the direction of the maximal principle stress, at least one local well and two adjacent wells are laid, and the reservoir stratum reconstruction by fracturing is carried out on thehorizontal wells; and a scheme that throughput of one well is asynchronous with that of the adjacent well but synchronous with that of the other well adjacent to the adjacent well is used, and the whole throughput period includes gas injection, soaking and oil extraction. CO2 can reduce the tension in a crude oil interface, the volume of crude oil is expanded, the density and viscosity of the crude oil are reduced, light components in the crude oil are extracted, and the permeability of regions near the wells are improved; stratum energy is supplemented, the problems that water injection exploitation of an unconventional stratum is low in spreading efficiency, easy to water channeling and hard to improve the final recovery efficiency are solved, and high and stable yield of an oil field isensured; and the asynchronous throughput method can alleviate the gas bypassing phenomenon of the local well, gas bypassing characteristic of the adjacent wells is used for displacement, and the total recovery degree is imporved.

Description

technical field [0001] The invention belongs to the technical field of oil and gas reservoir exploitation, and in particular relates to an ultra-low permeability tight oil reservoir for horizontal well injection of CO 2 A method for asynchronous throughput to replenish energy. Background technique [0002] The world's low-permeability oilfield resources are very rich and widely distributed, and basically all oil-producing countries have such oilfields. At present, with the continuous deepening of exploration and development and the further development of reservoir transformation methods, the reserves and production of low-permeability oil reservoirs in my country have increased significantly. Efficient development of such oil and gas reservoirs has become an important task for domestic and foreign petroleum workers. The production practice of unconventional oil and gas reservoirs at home and abroad has shown that fracturing horizontal wells is an effective way to develop suc...

Claims

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Application Information

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IPC IPC(8): E21B43/16
CPCE21B43/164
Inventor 雷征东田昌炳李俊超蔚涛刘双双
Owner PETROCHINA CO LTD
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