Non-residue polymer fracturing fluid

A technology of polymer and fracturing fluid, which is applied in the field of fracturing fluid, can solve problems such as blockage of formation filling layers, reduce fracturing effect, and decrease permeability, and achieve easy flowback, enhanced sand-carrying performance, and increased permeability Effect

Inactive Publication Date: 2015-06-17
NORTHWEST UNIV(CN) +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, at present, the vegetable gum fracturing fluid system is mainly used in our country. In this system, there are many water-insoluble substances and residues in the gel-breaking fluid, which will inevitably cause serious blockage of the formation and the filling layer supporting the fracture, and greatly reduce the permeability, thereby Greatly reduce the fracturing effect; for low-permeability and ultra-low-permeability oil and gas layers, it often leads to complete failure of fracturing

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] Add anionic polyacrylamide with a mass fraction of 0.15% into water under stirring, then add fluorocarbon surfactant YM-312 with a mass fraction of 0.3%, ammonium persulfate capsules with a mass fraction of 0.01%, and ammonium persulfate capsules with a mass fraction of 0.2% The composite crosslinking agent (the rest is water, and the sum of the mass percentages of each component is 100%) is stirred evenly to obtain a polymer fracturing fluid, which is suitable for fracturing reservoirs below 40°C.

[0025] The composite crosslinking agent is an aqueous solution of zirconium, aluminum, iron, and chromium salts of tartaric acid with a mass percentage concentration of 10%, wherein the mass ratio of zirconium oxychloride, aluminum chloride, ferrous chloride, and chromium chloride used in the reaction is It is 3:1:0.5:1.

Embodiment 2

[0027] Under stirring, add anionic polyacrylamide with a mass fraction of 0.25% into water, then add fluorocarbon surfactant TF-280 with a mass fraction of 0.3%, ammonium persulfate capsules with a mass fraction of 0.02%, and ammonium persulfate capsules with a mass fraction of 0.4% The composite cross-linking agent (the rest is water, and the sum of the mass percentages of each component is 100%) is stirred evenly to obtain a polymer fracturing fluid, which is suitable for reservoir fracturing at 40°C to 80°C.

[0028] The composite crosslinking agent is an aqueous solution of zirconium, aluminum, iron, and chromium salts with a concentration of 15% by mass of tartaric acid, lactic acid, and citric acid (1:1:1 by mass ratio), wherein the zirconium oxychloride used in the reaction , aluminum chloride, ferrous chloride, chromium chloride mass ratio is 4:2:0.7:1.2.

Embodiment 3

[0030] Add anionic polyacrylamide with a mass fraction of 0.45% into water under stirring, then add fluorocarbon surfactant TF-280 with a mass fraction of 0.3%, potassium sulfate capsules with a mass fraction of 0.03%, and 0.6% Composite cross-linking agent (the rest is water, the sum of the mass percentages of each component is 100%), and the polymer fracturing fluid is obtained by stirring evenly. The polymer fracturing fluid is suitable for reservoir fracturing at 80°C to 120°C.

[0031] The composite cross-linking agent is an aqueous solution of zirconium, aluminum, iron, and chromium salts with a mass percent concentration of 15% of lactic acid, citric acid, and malonic acid (1:2:1 in mass ratio), wherein the oxychlorine used in the reaction The mass ratio of zirconium chloride, aluminum chloride, ferrous chloride and chromium chloride is 4:2:0.7:1.2.

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Abstract

The invention provides a non-residue polymer fracturing fluid. The system of the fracturing fluid comprises 0.15 to 0.45% of a polymer thickening agent, 0.2 to 0.4% of a cleanup additive, 0.01 to 0.08% of a gel breaker and 0.2 to 0.6% of a composite cross-linking agent, with the balance being water with a pH value of 6 to 7. A preparation method for the fracturing fluid comprising the following steps: adding the polymer thickening agent into the water; then adding the cleanup additive, the gel breaker and the composite cross-linking agent; and carrying out uniform mixing under stirring so as to obtain the fracturing fluid. According to the invention, a polymer is used as the thickening agent and is reacted with the composite cross-linking agent to form a gel; the system carries sand in virtue of the gel; after the gel is broken with the gel breaker, the fracturing fluid has a non-residue characteristic similar to the non-residue characteristic of a clean fracturing fluid; and the fracturing fluid is especially applicable to fracturing transformation of low-permeability and ultralow-permeability reservoir strata.

Description

technical field [0001] The invention relates to a fracturing fluid used in the field of oil and gas field exploitation, in particular to a residue-free polymer fracturing fluid applied to the fracturing of low-permeability and ultra-low-permeability oil and gas wells at 20-120°C. Background technique [0002] Fracturing has become one of the main measures for increasing production and injection of oil and gas wells. As an important part of fracturing technology, the quality of fracturing fluid plays a key role in fracturing stimulation. After the 1990s, foreign researchers began to develop polymer-free water-based fracturing fluids. Currently, the fracturing fluids are mainly water-based fracturing fluids. An ideal water-based fracturing fluid should have sufficient viscosity to carry proppant, flow back quickly after fracturing, leave no residue in the fracture, and not damage the formation. However, at present, the vegetable gum fracturing fluid system is mainly used in...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K8/68
CPCC09K8/685C09K8/602C09K8/882C09K2208/26
Inventor 王玲燕谢志海王海力腾晓晓张瑜王珉许亮红
Owner NORTHWEST UNIV(CN)
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