Well flushing fluid for relieving damage of drilling fluid in low permeability sandstone gas layer and preparation method thereof

A technology of drilling fluid and flushing fluid, which is applied to the flushing fluid and its preparation to relieve the damage of drilling fluid in low-permeability sandstone gas layers. In the field of ancient low-permeability sandstone reservoirs in Changqing, it can solve the problem of severe damage and reduce damage. , improve efficiency and good compatibility

Active Publication Date: 2015-10-21
BC P INC CHINA NAT PETROLEUM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

As the filtrate enters the reservoir with the increase of time and the increase of the liquid column pressure (for example, to prevent collapse) and the strong capillary force of the reservoir itself, its immersion depth is also increasing, so the damage it produces is particularly serious and difficult to overcome.

Method used

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  • Well flushing fluid for relieving damage of drilling fluid in low permeability sandstone gas layer and preparation method thereof
  • Well flushing fluid for relieving damage of drilling fluid in low permeability sandstone gas layer and preparation method thereof
  • Well flushing fluid for relieving damage of drilling fluid in low permeability sandstone gas layer and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] The following components are used to prepare the flushing fluid for removing the damage caused by the drilling fluid of the ancient low-permeability sandstone gas layer in Changqing. According to the weight percentage, the weight ratio of surfactant is 0.05-0.1%, the weight ratio of chloroform as organic solvent is 8-10%, and formic acid The weight ratio of potassium is 5.0-6.0%, the weight ratio of hydrogen peroxide is 0.5-0.8%, the weight ratio of hydrofluoric acid is 0.5%-0.8%, and the balance is water. It is mixed to make the well flushing that relieves the damage of drilling fluid in the ancient low-permeability sandstone gas layer of Changqing liquid.

[0022] 1. Experimental Evaluation of Well Flushing Fluid for Improving Recovery Value of Gas Permeability After Injury in Example 1

[0023] According to the natural gas industry standard of the People's Republic of China "SY / T6540-2002 Indoor Evaluation Method for Drilling Fluid and Completion Fluid Damage to Rese...

Embodiment 2

[0039] The following components are used to prepare the flushing fluid for removing the damage caused by the drilling fluid in the ancient low-permeability sandstone gas layer in Changqing, using 85.6% by weight of clean water, 0.1% by weight of surfactant, and 8% by weight of chloroform as an organic solvent , Potassium formate 5.0% by weight, hydrogen peroxide 0.7% by weight, and hydrofluoric acid 0.6% by weight, mixed to make a well flushing fluid for removing damage from drilling fluids in Changqing ancient low-permeability sandstone gas reservoirs.

Embodiment 3

[0041] The following components are used to prepare the flushing fluid for removing the damage caused by the drilling fluid in the ancient low-permeability sandstone gas layer in Changqing, using 82.6% by weight of clean water, 0.1% by weight of surfactant, and 10% by weight of chloroform as an organic solvent , 6.0% by weight of potassium formate, 0.8% by weight of hydrogen peroxide, and 0.5% by weight of hydrofluoric acid, mixed to make a well-washing fluid for removing damage from drilling fluids in Changqing ancient low-permeability sandstone gas reservoirs.

[0042] In the application of Examples 2 and 3, the well flushing fluid system also exhibits the obvious improvement of the recovery rate of the permeability, the ability to overcome the water locking effect, and the simple and easy formulation and mixing process.

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Abstract

The invention discloses a flushing fluid of relieving damage of low permeable sandstone air layer drilling fluid and a preparation method thereof. The flushing fluid comprises 0.05-0.1 percent of surface active agent by weight percent, 8-10 percent of organic solvent chloroform by weight percent, 5.0-6.0 percent of potassium formate by weight percent, 0.6-0.8 percent of oxydol by weight percent, 0.5-0.8 percent of hydrofluoric acid by weight percent, and the balance of water. The flushing fluid can allow low permeable sandstone gas pool to become weak hydrophilic from strong hydrophilic, eliminates reservoir capillary force, resolves solid phase of an entering part, break blockade, improves efficiency of gas-drive water, and lowers the solid phase damage, and therefore, the permeability and the recovery rate of core is obviously improved.

Description

technical field [0001] The invention relates to a well-flushing fluid, in particular to a well-flushing fluid for relieving the damage of drilling fluid in low-permeability sandstone gas layers and a preparation method thereof, which can be applied to ancient low-permeability sandstone reservoirs in Changqing. Background technique [0002] Paleo-low permeability gas reservoirs in Changqing generally have the characteristics of high muddy cement content, high water saturation, high capillary pressure, strong water sensitivity, fine pore throat, poor permeability, complex structure, and serious heterogeneity. There is excess capillary pressure when the initial water saturation is lower than the irreducible water saturation, and capillary self-absorption is likely to occur when foreign fluid enters, making it difficult or even impossible to flow back the foreign fluid that invades the reservoir. Serious water lock damage is formed. The greater the water lock damage, the lower t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C09K8/524C09K8/52
Inventor 董宏伟张建斌林海贾俊赵向阳郑玉辉董海东蒋振伟张振活凡帆陈磊张宇崔贵涛刘婷婷赵雷郝超曲波蔺文洁苏欢
Owner BC P INC CHINA NAT PETROLEUM CORP
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