Concentric dual-tube separated injection CO2 tubular column and application method thereof

Abstract

The invention relates to the technical field of oilfield development gas injection, in particular to a concentric dual-tube separated injection CO2 tubular column applied to CO2 separated injection. According to the concentric dual-tube separated injection CO2 tubular column, a sleeve pipe, an outer pipe and an inner pipe are sleeved in succession, and an outer door, an upper packer, a gas separation valve, a lower packer and a gas injection valve are connected to the outer pipe in succession; the lower end of the inner pipe is firstly connected with an inner door and then is connected with the gas separation valve; and an inserting sealing mechanism, a locking mechanism and an anti-return mechanism are arranged in the gas separation valve. An application method of the concentric dual-tubeseparated injection CO2 tubular column comprises the steps that an outer tubular column is fed; the packers are packed; the inner pipe is fed to be inserted and sealed and is locked; gas is injected;an inner door press well is opened; the inner pipe is lifted up; an outer door press well is opened; and the packers are unpacked, and the outer tubular column is lifted up. The concentric dual-tubeseparated injection CO2 tubular column is provided with an inner door and an outer door, and the problems about press well channels are solved; the anti-return mechanism is arranged, and production issafe; and the inserting sealing mechanism and the locking mechanism are arranged, and sealing failures are avoided. The gas seal packers provided with anchors and provided with no well washing channel are adopted, reliable separation is guaranteed, and the problem of sealing failures caused by packer upward movement due to the too large lower pressure difference is avoided.

Description

Technical field [0001] The invention relates to the technical field of stratified gas injection in the development of petroleum industry oilfields, in particular to separate CO injection with concentric double pipes 2 Pipe string and method of use. Background technique [0002] In the process of oilfield development, water injection is the most important way to supplement energy in the formation. In order to solve the difference in water absorption capacity between different oil layers and on the plane, and to adjust the water injection volume of different oil layers reasonably, layered water injection technology has been widely implemented in the oilfield development process. [0003] In the layered water injection technology, the concentric double pipe split injection is a common technology, such as Chinese patent application number 201020165475.3, application date April 16, 2010, the patent name "highly deviated well surface water distribution concentric double pipe split inject...

AI Technical Summary

Problems solved by technology

[0006] ①The packers are all equipped with a well-washable mechanism, which has poor reliability in the downhole. Once it fails, it will cause interlayer collusion or annular pressure production, which will have a negative impact on the effect of layered gas injection and production safety, and cannot be used The flushable packer replaces the flushable packer but the well cannot be flushed

[0007] ② There is no anti-ejection tool downhole. When the surface gas injection wellhead, process and other facilities accidentally leak, the CO injected into the oil layer will 2 It will spray out of the wellhead, which may cause a safety accident

[0008] ③When the seal insertion device receives the thrust from below to a certain value under a certain interlayer pressure difference, it will push the insertion part and the inner oil pipe upwards, causing the seal to fail

[0009] ④ No consideration was given to replacing the corrosion inhibitor solution in the oil casing annulus above the upper packer to protect the upper casing and prevent CO 2 corrosion

Images