High temperature-resisting cleaning CO2 foam fracturing liquid suitable for unconventional oil and gas reservoir development

Abstract

The invention discloses high temperature-resisting cleaning CO2 foam fracturing liquid suitable for unconventional oil and gas reservoir development. The high temperature-resisting cleaning CO2 foam fracturing liquid in gas phase is CO2; the high temperature-resisting cleaning CO2 foam fracturing liquid in liquid phase is high temperature-resisting cleaning fracturing liquid; the foam mass is 52 percent to 75 percent. The high temperature-resisting cleaning CO2 foam fracturing liquid is prepared from the following raw materials in percentage by weight: 0.3 to 0.65 percent of thickening agent, 0.2 to 0.5 percent of viscosity synergist, 0.2 to 0.3 percent of pH (Potential of Hydrogen) value modifier, 0 to 0.2 percent of high-temperature stabilizing agent, 0.01 to 0.1 percent of gel breaker and water, wherein the thickening agent is prepared from acrylamide, vinylpyrrolidone, maleic acid, anionic functional monomers, an initiating agent, inorganic salt and the like; the viscosity synergist is mainly prepared from an anionic surfactant; the pH value modifier is mainly prepared from an organic acid. According to the high temperature-resisting cleaning CO2 foam fracturing liquid disclosed by the invention, the temperature-resisting ability is up to 140 DEG C, the sand carrying performance is excellent, the frictional resistance is low, the foam stability is strong, the content of residual slag is extremely low, the stratum compatibility is good, back flowing is easy, the construction effect is quickly obtained, and important significances to effective development of an unconventional oil and gas reservoir and protection of a reservoir stratum are obtained.

Description

technical field [0001] The invention relates to the technical fields of oilfield chemistry and fracturing stimulation, in particular to a high-temperature-resistant clean CO2 suitable for unconventional oil and gas reservoir development. 2 Foam fracturing fluid. Background technique [0002] With the continuous reduction of high-quality oil and gas reservoirs in China, the development of unconventional oil and gas reservoirs has increasingly become the research focus of many experts and scholars. The development of unconventional oil and gas reservoirs mainly includes tight sandstone gas reservoirs, shale gas, coalbed methane, etc. In the development of such oil and gas reservoirs, fracturing operations are generally used to stimulate production, but currently there are many problems in fracturing operations, such as Low formation energy, severe water lock damage, difficult flowback of fracturing fluid, serious secondary pollution of fracturing, etc. These problems lead to ...

AI Technical Summary

Problems solved by technology

CO, which has been successfully applied at home and abroad in recent years 2 The foam fracturing fluid system is a cross-linked fracturing fluid system with guar gum as the thickening agent. This kind of foam fracturing fluid can meet the requirements of high temperature fracturing, but the fracturing fluid system has a high residue content after the gel is broken, and it is not easy to flow back. Great damage to the formation, and the foam gel formed by cross-linking has high friction resistance, which increases the difficulty of fracturing construction

In 2005, Schlumberger newly launched VES clean CO 2 Fracturing fluid technology effectively solves the problems of friction and residue damage, but its stability and temperature resistance are poor at low pH values, and its high cost hinders its popularization and application

[0004] Therefore, there is no ideal CO2 suitable for the development of unconventional oil and gas reservoirs at home and abroad. 2 Foamy fracturing fluid system, which greatly limits the development of such unconventional oil and gas reservoirs

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