Water lock removal agent for low-water-content oil well

A water-releasing agent, low water content technology, applied in wellbore/well components, drilling composition, production fluid, etc., can solve the problem of not fundamentally eliminating the water-locking effect, high cost, and injecting surfactants to reduce two-phase It can eliminate the two-phase seepage resistance, reduce the starting pressure, and increase the relative permeability of the oil phase.

Inactive Publication Date: 2016-07-06
CHINA UNIV OF PETROLEUM (EAST CHINA)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the cost of fracturing reconstruction is too high, and the injection of surfactant can only reduce the seepage resistance of two-phase flow, but does not fundamentally eliminate the water locking effect

Method used

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  • Water lock removal agent for low-water-content oil well
  • Water lock removal agent for low-water-content oil well

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0013] Take 10g of nano-silica with an original particle size of 15-30nm and 990g of ethylene glycol monobutyl ether and mix evenly to obtain a water-dissolving and locking agent with a mass fraction of nano-silica of 1%.

Embodiment 2

[0015] Take 30g of nano-silica with an original particle size of 15-30nm and 970g of ethylene glycol monobutyl ether and mix them evenly to obtain a water-splitting and locking agent with a mass fraction of nano-silica of 3%.

Embodiment 3

[0017] Take 50g of nano-silica with an original particle size of 15-30nm and 950g of ethylene glycol monobutyl ether and mix them evenly to obtain a water-splitting and locking agent with a mass fraction of nano-silica of 5%.

[0018] Add 1.5mL of water and 1.5mL of crude oil to each of the three graduated cylinders, then add 1.5mL of the hydrolysis-locking agents prepared in the above three examples to each of the three graduated cylinders, and put the graduated cylinders into a 70°C water bath , stand still and observe the dissolution status. Experiments show that without external stirring at 70°C, the interface between oil and water disappears obviously after 6-6.5 hours, and the whole system becomes a uniform and stable single-phase system, which shows that the oil-water interface can be eliminated by solubilizing oil and water with the water-dissolving and locking agent .

[0019] Table 1 system miscibility time

[0020] Nano silica mass fraction, %

Ethylen...

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Abstract

The invention provides a water lock removal agent for removing the water lock damage of a low-water-content oil well.The water lock removal agent is composed of nanometer silicon dioxide and ehtylene glycol monobutyl ether with initial granularity of 15-30 nm, wherein the weight of nanometer silicon dioxide accounts for 1-5% of the total weight.When the volume ratio of the water lock removal agent to water is 1:1, the oil phase and the water phase can be changed into one phase through the water lock removal agent within 6 hours by solubilizing the water phase and the oil phase, and therefore the permeation resistance of the two phases is eliminated; by means of the nanometer silicon dioxide, the hydrophily of rock surfaces can be enhanced, free water is adsorbed to rock surfaces to form water films, and therefore the relative permeation rate of the oil phase is increased, and the permeation start pressure of the oil phase is reduced.For the oil well suffering from water lock damage, the water lock removal agent with the same volume as the leakage volume is injected into a stratum through oil sleeve annulus according to the flushing fluid leakage volume recorded in the flushing work process; by closing the well for 6 hours or above and then opening the well for production, the water lock damage of the low-water-content oil well can be effectively relieved.

Description

Technical field: [0001] The invention relates to a water-blocking agent for releasing water-blocking damage of oil wells, which is used for reservoir protection of oil wells with low water content. Background technique: [0002] During the development of oilfields, due to operations such as pump replacement and pump inspection, it is necessary to use well-entry fluid to circulate and clean the casing annulus and tubing. At present, the water phase with surfactants is mainly used as the well-flushing fluid, but for the water content In lower oil wells, after the water phase in the well fluid invades the oil layer, a high water saturation zone will be formed around the wellbore, which changes the flow form of crude oil in the oil layer from single-phase flow to two-phase flow, greatly reducing the oil phase flow. The relative permeability increases the resistance of crude oil flow, thereby affecting the oil production of the oil well. The phenomenon that the water phase invade...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K8/58C09K8/584E21B43/22
CPCE21B43/16C09K8/58C09K8/584C09K2208/22C09K2208/10
Inventor 蒋平吴昊葛际江张贵才裴海华孙铭勤
Owner CHINA UNIV OF PETROLEUM (EAST CHINA)
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