A long-acting CO2 gas injection string and its operation method

Abstract

The invention discloses a long-acting CO2 gas-injecting pipe column and an operation method thereof. The long-acting CO2 gas-injecting column comprises an upper pipe column and a lower pipe column. The upper pipe column comprises an oil pipe which is arranged in a sleeve pipe in a sleeving mode. The oil pipe is provided with a circulating well-washing sliding sleeve, a hydraulic anchor, a ring-hanging device and a sealing inserting pipe in sequence from top to bottom. The lower pipe column comprises a sealing drum and a packer which are arranged on the oil pipe in sequence. The bottom of the lower pipe column is provided with a setting ball base and a double-grade check valve. The lower pipe column is fixed to the inner wall of the sleeve pipe through an anchor tile of the packer. Closing during water injecting can be achieved through the circulating well-washing sliding sleeve, and opening during backwashing can be achieved. According to the long-acting CO2 gas-injecting pipe column, the structure is simple, packing can be more reliable through the permanent packer, a down-hole well-closing function can be achieved through the multi-functional setting ball base, and down-hole well-closing can be more reliable through the double-grade check valve; through the circulating well-washing sliding sleeve and under the condition without moving pipe columns, the sliding sleeve can be started only through annular pressing, the operation of replacing annular protecting fluid can be conducted, the operation is more convenient and easy, and the cost is saved; and through the ring-hanging device, corrosion situations of pipe columns can further be monitored.

Description

technical field [0001] The invention belongs to the technical field of downhole gas injection used in petroleum exploitation, and in particular relates to a long-acting CO 2 Gas injection string and operation method. Background technique [0002] CO 2 Miscible flooding is a newly emerging technology in foreign countries in recent years. 2 Miscible, can supplement formation energy to improve recovery. Field tests have been gradually carried out in various domestic oilfields. At present, general gas injection strings are mainly used. Jidong Oilfield adopts Y221 packer + hydraulic anchor structure; "button tubing + DGL packer" general injection string; Shengli Oilfield uses Y441 packer; Jilin Oilfield and Changqing Oilfield use Halliburton PHL packer Y441. According to research, CO 2 There are few supporting tools for driving strings, and there are the following problems: 1. Due to the high pressure and the change of temperature and pressure, the strings have peristalsis. ...

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Problems solved by technology

[0003] The technical problem to be solved by the present invention is to provide a long-acting CO 2 The gas injection string and its operation method solve the problems of easy failure of the packer, too complicated opening and closing of sliding sleeve during well flushing, and reliability of snubbing operation

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