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Method for improving water flooding effect of water injection well of ultra-low-permeability fractured reservoir

A fracture and oil reservoir technology, applied in the field of improving the water flooding effect of water injection wells in ultra-low permeability fractured oil reservoirs, can solve the problems of poor oil layer physical properties, low matrix seepage capacity, low single well production, etc. The effect of alternate space

Inactive Publication Date: 2020-08-21
PETROCHINA CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

After a long period of water injection development, the reservoir has poor physical properties and low matrix seepage capacity, resulting in limited displacement distance of the injected water matrix. At the same time, due to the development of micro-fractures in the reservoir, the injected water is easy to rush along the natural fractures, forming water flow The dominant channel leads to premature high water cut or water flooding of the oil well at the fracture line position, while the lateral oil well does not work, the single well production is low, and the overall development effect of the block is poor
[0003] The water injection wells in the early stage mainly adopt the method of acidizing plugging removal and increasing injection. This technology can only solve the problem of plugging near the wellbore, but cannot improve the water injection system. Therefore, it is urgent to carry out research and experiments on new refracturing technology for water injection wells in this type of reservoir. Establish an effective displacement system to make the injected water advance evenly and improve the effective displacement and ultimate recovery of water injection wells

Method used

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  • Method for improving water flooding effect of water injection well of ultra-low-permeability fractured reservoir

Examples

Experimental program
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Effect test

Embodiment 1

[0027] Embodiment 1 (white 404-39 well)

[0028] In order to solve the problem of uneven water flooding caused by the long-term water injection development of ultra-low permeability oilfields, the development of natural micro-fractures, and the formation of dominant water flow channels. This embodiment provides a figure 1 The shown method for improving the water flooding effect of water injection wells in ultra-low permeability fractured reservoirs includes the following steps:

[0029] Step 1: Blocking agent optimization: use CDD-3 blocking agent with a particle size of 3-6mm, and a particle density of 1.06g / cm 3 , the softening point is 40°C, the melting point is 58°C, and 600kg of plugging agent is prepared;

[0030] Step 2: Preparation of proppant: In order to support micro-fractures, proppant only adopts small particle size and reduced dosage to achieve the purpose of lateral water diversion. The proppant particle size is 70-100 mesh, and the dosage is 25m 3 .

[0031...

Embodiment 2

[0035] Step 1: Blocking agent optimization: use CDD-3 blocking agent with a particle size of 3-6mm, and a particle density of 1.06g / cm 3 , the softening point is 40°C, the melting point is 58°C, and 500kg of plugging agent is prepared;

[0036] Step 2: Preparation of proppant: In order to prop up micro-fractures, proppant only adopts small particle size and reduced dosage to achieve the purpose of lateral water diversion. The proppant particle size is 70-100 mesh, and the dosage is 20m 3 .

[0037] Step 3: Plugging agent injection: use guar gum cross-linking fluid to carry the blocking agent, at 3.0m 3 / min displacement, according to the amount of 125 kg for the first stage, 165 kg for the second stage, and 210 kg for the third stage, it is pumped in three stages, and 40m is injected between each stage 3 The base fluid is used as the spacer fluid. After the pumping of the plugging agent is completed, active water is used to clean the plugging agent in the wellbore into the f...

Embodiment 3

[0040] Step 1: Blocking agent optimization: use CDD-3 blocking agent with a particle size of 3-6mm, and a particle density of 1.06g / cm 3 , the softening point is 40°C, the melting point is 58°C, and 570kg of plugging agent is prepared;

[0041] Step 2: Preparation of proppant: In order to support micro-fractures, proppant only adopts small particle size and reduced dosage to achieve the purpose of lateral water diversion. The proppant particle size is 70-100 mesh, and the dosage is 30m 3 .

[0042] Step 3: Plugging agent injection: use guar gum cross-linking fluid to carry the blocking agent, at 3.0m 3 / min displacement, according to the amount of 140 kg for the first stage, 190 kg for the second stage, and 240 kg for the third stage, it is pumped in three stages, and 50m is injected between each stage 3 The base fluid is used as the spacer fluid. After the pumping of the plugging agent is completed, active water is used to clean the plugging agent in the wellbore into the f...

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Abstract

The invention discloses a method for improving the water flooding effect of a water injection well of an ultra-low-permeability fractured reservoir. Firstly, reservoir water flow preferential migration passages are temporarily blocked, multi-stage temporary blockage is performed through CDD-3 oil-soluble blocking agents to form wedge-shaped blockage, streaming of injected water along the preferential migration passages or natural fractures is controlled, and untimely high water content or water logging at a water line position of the oil well is restrained. Specifically, by adopting guanidinegum crosslinking liquid and injecting 500-600 kg of blocking agents at three stages and a low emission, the water flow preferential migration passages are blocked. Then, according to the ultra-low-permeability fractured reservoir and water flooding features, volume fracturing is performed on the water injection well of the reservoir to form a complex fracture network, a water flooding volume is increased, and the aim of wideband uniform water flooding is realized.

Description

technical field [0001] The invention relates to the field of ultra-low permeability oil reservoirs, in particular to a method for improving the water flooding effect of water injection wells in ultra-low permeability fractured oil reservoirs. Background technique [0002] Ultra-low permeability reservoirs are characterized by poor reservoir physical properties, low formation pressure coefficient and relatively developed natural fractures. In order to realize the effective development of this type of reservoir scale, water injection is used to supplement energy development. In the early stage of development, water injection wells mainly adopt composite perforation and deflagration fracturing. The perforation degree is 60-80%, and then direct injection. The injection-production well pattern is diamond Anti-nine o'clock well pattern. After a long period of water injection development, the reservoir has poor physical properties and low matrix seepage capacity, resulting in limi...

Claims

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Application Information

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IPC IPC(8): E21B43/20E21B43/26E21B33/13
CPCE21B43/20E21B43/261E21B33/13
Inventor 李转红李向平陆红军张矿生卜向前齐银卜军汪澜杨军侠王飞
Owner PETROCHINA CO LTD
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