A mixed gas foam fracturing fluid system and its preparation

Abstract

The invention provides a mixed gas foam cracking liquid system and preparation thereof. The mixed gas foam cracking liquid system comprises a gas phase and a liquid phase according to a volume ratio of (2 to 5):1, wherein the gas phase is nitrogen gas; on the basis of 100% of total weight of liquid phase, the liquid comprises the following components in percentage by weight: 0.8 to 1.2% of foamingagent, 0.3 to 0.8% of thickener, 0.8 to 1.2% of foam stabilizer, 45 to 55% of liquid carbon dioxide, and the balance of simulating stratum water. The mixed gas foam cracking liquid system has the advantages that the energy increasing, viscosity increasing, foaming and foam stabilizing functions are integrated, and the mixing advantage of carbon dioxide and nitrogen is fully realized.

Description

technical field [0001] The invention relates to the field of oil exploitation, in particular to a mixed gas foam fracturing fluid system and its preparation. 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, the foam fracturing technology had developed rapidly. For foam fracturing construction, nitrogen foam fracturing was initially used, and carbon dioxide foam fracturing technology was tried in the early 1980s, which is often used for fracturing operations in medium-deep wells and high-temperature wells under normal pressure. [0003] Nitrogen foam fracturing fluid is used as a medium for creating fractures and carrying sand, and its performance improvement has always been a subject of research. N 2 It is an inert gas and can be compatible with all base fluids (water, brine,...

AI Technical Summary

Problems solved by technology

Carbon dioxide foam fracturing fluid is suitable for a wide range of temperatures and can also meet high temperature requirements. However, chemical additives such as foaming agents and bactericides must be added to the fracturing fluid system. After the gel is broken, the residue content is high, it is not easy to flow back, and it will cause 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 CO 2 Clean fracturing fluid technology, VES 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

[0005] It is worth noting that at present, there is not a large amount of foam fracturing fluid using a mixture of carbon dioxide and nitrogen in China. The mixed use of the two gases can give full play to their respective advantages, more effectively improve the effect of foam fracturing, and increase reservoir productivity.

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