A water plugging and fracturing method for high water cut old wells in low permeability oil and gas fields

A technology for oil and gas fields and water fracturing, which is applied in chemical instruments and methods, earthwork drilling and production, wellbore/well components, etc. It can solve problems such as small effective range of fractures, failure to divert fractures, and water flooding of oil well fractures. To achieve the effects of expanding the effective range of action, improving production efficiency and benefits, and stabilizing production for a long period

Active Publication Date: 2021-05-14
杨凌单色生物科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

What is worrying is that for refracturing operations in low-permeability oil and gas fields developed by water injection, especially oil and gas wells with side, bottom water, or near water injection wells, if the conventional fracturing technology is used, due to the continuous expansion of fractures, It is easy to extend to the water layer, or to cause channeling with nearby water injection wells, which will cause a large number of oil wells to stop production or even be scrapped, seriously affecting oil field benefits; at the same time, conventional fracturing technology cannot realize fracture diversion, and can only extend on the basis of the original fractures , the effective range of fractures is small, and the repeated fracturing construction of this process method has poor fracturing stimulation effect and is more likely to lead to the risk of water production in oil wells; the existing diversion fracturing technology requires a large amount of temporary plugging agents and other supplementary products. The construction cost is increased, and the possibility of construction sand plugging and failure to generate new fractures coexists, and its success rate is low. Not only can it not solve the problem of water channeling, but it may cause new oil well fractures and water flooding problems

Method used

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  • A water plugging and fracturing method for high water cut old wells in low permeability oil and gas fields
  • A water plugging and fracturing method for high water cut old wells in low permeability oil and gas fields
  • A water plugging and fracturing method for high water cut old wells in low permeability oil and gas fields

Examples

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Effect test

Embodiment 1

[0031] A method for water plugging and fracturing of old wells with high water content in low-permeability oil and gas fields: use a cement truck to inject cement slurry into the formation, and then use a fracturing vehicle to inject high-viscosity suspended sand fluid into the formation with a low displacement, so that the original fractures in the formation fractures The proppant is suspended, and the cement slurry is pushed to the end of the fracture together, and finally the surfactant fracturing fluid is injected with a large displacement for fracturing construction. The initial setting time of the cement slurry is 6 to 7 hours.

[0032] The cement slurry is made by mixing 50%~70% G grade cement, 28%~49.5% clear water and 0.5~2.0% retarder according to the above mass ratio.

[0033] The high-viscosity suspension liquid is composed of 3.5%~4.0% oligoaminosuccinic acid fatty acid ester salt, 0.4%~0.5% formic acid, 1.0%~2.0%KCl and 93.5%~95.1%H 2 O is mixed according to the ...

Embodiment 2

[0036] A water plugging and fracturing method for high water-cut old wells in low-permeability oil and gas fields, comprising the following steps:

[0037] The first step: preparation before fracturing construction, prepare cement slurry, high-viscosity suspended sand fluid and surfactant fracturing fluid;

[0038] Step 2: Start the construction, first use active water to test the extrusion, check the sealing situation and judge whether the oil layer absorption meets the requirements;

[0039] Step 3: After the test extrusion meets the requirements, inject the cement slurry into the formation with a cement truck; the initial setting time of the cement slurry is 6 to 7 hours;

[0040] Step 4: Use the fracturing truck to pump high-viscosity suspended sand fluid into the formation with low displacement; suspend the original proppant in the formation fracture, and push the cement slurry to the end of the fracture;

[0041] Step 5: Replace the high-viscosity suspended sand fluid w...

Embodiment 3

[0051] It is basically the same as Example 2, except that the cement slurry is mixed with 70% G grade cement, 28% clear water and 2.0% retarder according to the above mass ratio.

[0052] The suspension liquid of described high viscosity is made of 4.0% oligoaminosuccinic acid fatty acid ester salt, 0.5% formic acid, 2.0%KCl and 93.5%H 2 O is mixed according to the above mass ratio.

[0053] The surfactant fracturing fluid is composed of 4.0% oligomeric aminosuccinic acid fatty acid ester salt, 0.5% formic acid, 2.0% KCl and 93.5% H 2 O is mixed according to the above mass ratio.

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Abstract

The invention relates to a method for water plugging and fracturing of old wells with high water content in low-permeability oil and gas fields, which is characterized in that cement slurry is injected into the formation by a cement truck, and then high-viscosity suspended sand is injected into the formation by a fracturing vehicle with a low displacement Suspend the original proppant in the formation fractures, and push the cement slurry to the end of the fracture together, and finally inject a large amount of surfactant fracturing fluid for fracturing construction. The initial setting time of the cement slurry is 6~ 7 hours. The method of the invention can effectively prevent water channeling and flooding caused by uncontrolled extension of cracks during the fracturing process, and can realize in-fracture diverting fracturing without a diverting agent, which is beneficial to improving the fracturing construction effect.

Description

technical field [0001] The invention relates to a fracturing method, in particular to a water plugging and fracturing method for high water content and old wells in low permeability oil and gas fields. It belongs to the technical field of oil and gas field production and development. Background technique [0002] Hydraulic fracturing technology is the main production stimulation measure of major oil and gas fields, especially in the production and development process of low permeability oil and gas fields, it plays an irreplaceable role in improving the production and recovery of oil and gas fields, and has achieved good results. However, with the development of production and development, the energy of the formation gradually decreases, and the production declines. Most major oil and gas fields adopt production and development methods such as water injection, which leads to many serious problems such as high water cut in oil wells, even water flooding and water channeling i...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): E21B33/13E21B43/267C09K8/68C09K8/467
Inventor 肖良飞陈柯全刘畅
Owner 杨凌单色生物科技有限公司
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