A two-stage self-sealing thermal recovery packer

Abstract

The invention relates to a double-stage self-sealing thermal recovery packer which is a down-hole tool for heavy oil thermal recovery and comprises an upper joint, an upper sheath, an upper sealing sleeve, an upper central tube, expansion solid, a lower sheath, an inner cone, a lower sealing sleeve, a combined slider, an upper piston, a lower piston, a cylinder and a lower central tube. The upper joint, the upper central tube, the inner cone and the lower central tube are sequentially connected with one another in a threaded manner from top to bottom, the upper sheath is connected onto the upper joint, the upper sealing sleeve is arranged in the upper sheath, the corresponding expansion solid is filled in the upper sealing sleeve, the lower sheath is respectively connected with the upper sealing sleeve and the lower sealing sleeve in an interference manner, the lower sheath and the lower sealing sleeve are sleeved on the inner cone, the cylinder is connected with the lower central tube in a threaded manner, the combined slider, the upper piston and the lower piston are sequentially arranged inside the cylinder from top to bottom, and the corresponding expansion solid is arranged between the upper piston and the lower piston. The double-stage self-sealing thermal recovery packer is of a double-stage sealing structure, accordingly, thermodynamic automatic setting and hydraulic-assisted setting effects can be realized, and the double-stage self-sealing thermal recovery packer has the advantages of short setting time, durability in setting, good sealing performance, smooth unsetting and the like.

Description

technical field [0001] The invention relates to a downhole tool used for injecting high-temperature and high-pressure steam to exploit heavy oil, and belongs to the technical field of oil exploitation. Background technique [0002] Injection of high-temperature and high-pressure steam is an effective process for heavy oil recovery. The thermal recovery packer is an important component of the steam injection string, which can prevent high-temperature and high-pressure water vapor from entering the annular space formed by the oil casing and heat-insulating pipe, thereby improving the thermal injection efficiency and protecting the oil layer casing. At present, there are mainly two types of thermal recovery packers used in the field: heat-sensitive type and thermal expansion fluid type. The heat-sensitive thermal recovery packer mainly adopts bimetallic thermal expansion materials. By utilizing the different thermal expansion coefficients of bimetallic materials, when the down...

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Problems solved by technology

The thermal expansion liquid contained in this kind of packer is volatile. If it is stored for a long time and goes downhole, the sealing performance will decrease due to the reduction of the expansion liquid. The tube is bent by heat, and the casing is eventually discarded

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