Clean carbon dioxide foam fracturing fluid and preparation method thereof

Abstract

The invention discloses clean carbon dioxide foam fracturing fluid and a preparation method thereof, and relates to the technical field of oilfield chemistry and fracturing production increase. The carbon dioxide foam fracturing fluid is mainly composed of a base solution, a foaming agent, a gel breaker and liquid carbon dioxide with the mass ratio being 100 to 0.15-0.45 to 0.02-0.08 to 100-900. The base solution is formed by 0.2%-0.55% of a thickening agent and water. The thickening agent is mainly formed by bisacrylamide, vinyl pyrrolidone, kation unsaturated monomer, anion unsaturated monomer, an initiator, sodium carbonate, an emulsifying agent and a hydrotropy agent. The foaming agent is mainly formed by hexadecyl dimethyl tertiary amine, dimethyl sulfate, caustic soda flakes, potassium persulfate and solvent. The clean carbon dioxide foam fracturing fluid has the advantages of being high in foam stability, high in temperature resistance and shear resistance, high in sand-carrying performance, wide in applicable temperature range, extremely low in residue content, high in backflow performance, and small in secondary damage to a reservoir after fracturing, thereby improving the fracturing effect and increasing the reservoir productivity.

Description

technical field [0001] The invention relates to the technical fields of oilfield chemistry and fracturing stimulation, in particular to a clean carbon dioxide foam fracturing fluid and a preparation method thereof. Background technique [0002] The use of foam fracturing has been around for more than 30 years. Foam fracturing began in the 1960s in foreign countries, and the foam fracturing technology gradually matured in the 1970s and 1980s. By the mid-1980s, foam fracturing technology had developed rapidly. Especially in gas well fracturing, from 1986 to 1990, the proportion of foam fracturing increased from 20% to 50%. Since the 1990s, more than 90% of gas wells in North America (the United States and Canada) have used foam fracturing technology, and 30% of oil wells have used CO 2 Foam fracturing fluid. In recent years, foam fracturing technology has developed rapidly, especially gas well fracturing, and the market share of foam fracturing technology is constantly incr...

AI Technical Summary

Problems solved by technology

initial CO 2 Foam fracturing fluid uses linear glue (guar gum) as the liquid phase to form a stable foam. In recent years, CO 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 is suitable for a wide range of temperatures and can also meet high temperature requirements, but a foaming agent must be added to the fracturing fluid system And chemical additives such as fungicides, high residue content after gel breaking, not easy to flow back, great damage to the formation, and the foam gel formed by cross-linking has high viscosity and increased friction, which further increases the difficulty of fracturing construction

In 2005, Schlumberger newly launched VES clean CO 2 Fracturing fluid technology, VES (organic viscoelastic surfactant) fracturing fluid, effectively solves the problems of friction and residue damage, but the temperature resistance performance needs to be improved, and its high cost hinders its popularization and application

[0004] It is worth noting that there is currently no large-scale application of clean CO in China. 2 Foam fracturing fluid, which greatly limits the development of some special reservoirs that require foam fracturing operations

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