Composite miscible fracturing method of chemical agent and carbon dioxide in low-permeability reservoirs

Abstract

The invention provides a compound miscible fracturing method of chemical agent and carbon dioxide for low-permeability reservoirs, and provides a compound miscible fracturing method of chemical agent and carbon dioxide applied to the transformation of low-permeability reservoirs, which uses matching chemical additives and carbon dioxide mixed pump injection Restructuring of the formation, including non-flowback acid and chemical agent plugging removal, slick water and chemical agent fracturing, carbon dioxide and chemical agent diversion fracturing and miscible steps are carried out in an orderly manner. The invention can effectively solve the problems existing in the development of low-permeability reservoirs, such as strong sensitivity, low reservoir permeability, insufficient energy, rapid oil well production decline, poor effect of conventional measures and short cycle, etc., and realizes low-permeability reservoir seepage The dredging of channels, the improvement of crude oil fluidity and the construction of complex network three-dimensional fracture system, the effective protection of reservoirs, the single well productivity and the production degree of low permeability reservoirs have been greatly improved.

Description

technical field [0001] The invention belongs to the field of oil and gas development, and in particular relates to a chemical agent and carbon dioxide composite miscible fracturing method applied to the stimulation of low-permeability oil reservoirs. Background technique [0002] Low permeability oil and gas fields play an important role in my country's oil and gas development. The distribution of low-permeability oil and gas resources in my country is characterized by a large number of oil and gas, many types of oil and gas reservoirs, and a wide distribution area. Among the proven reserves, the proportion of low-permeability oil and gas reserves accounts for more than 2 / 3 of the national reserves, and the development potential is huge. . [0003] The oil and natural gas resources discovered in my country in the past 10 years have increased reserves of 400 million to 500 million tons every year, but about 70% are low-permeability and ultra-low permeability oil and gas reser...

AI Technical Summary

Problems solved by technology

The main characteristics of low-permeability oil and gas reservoirs are extremely low permeability, strong reservoir sensitivity, easy to be polluted, and difficult to recover after pollution. In addition, this type of oil and gas reservoir has fast elastic energy depletion, difficult water injection, and oil well production declines rapidly, and soon will enter the inefficient development stage

[0004] In the prior art, conventional fracturing stimulation operations are used for low-permeability oil and gas reservoirs. Due to the poor physical properties of low-permeability oil and gas reservoirs, high viscosity of crude oil, water sensitivity and salt sensitivity are prone to occur, and the formation is easy to be polluted. In terms of process implementation also have great limitations

Images