Multi-stage delayed steam injection string

Abstract

The present invention provides a multi-stage delayed steam injection pipe string, which includes a delayed steam injection assembly and at least one layered steam injection assembly arranged sequentially from top to bottom, and the delayed steam injection assembly includes a delayed steam injection valve and Two upper packers, the delay steam injection valve includes an inner cylinder and an outer casing, a steam injection annulus is formed between the outer casing and the inner cylinder, and a steam inlet hole connected with the steam injection annulus is provided on the side wall of the inner cylinder , the side wall of the casing is provided with a steam outlet hole connected with the steam injection annulus, and the steam injection annulus is filled with gel that can block the steam inlet and outlet holes; the layered steam injection component includes a layered injection The steam valve and the lower packer, the layered steam injection valve includes a valve body, a sliding sleeve and a throwing ball. The side wall of the valve body is provided with a steam injection hole, and the sliding sleeve has a first position for blocking the steam injection hole and makes the steam injection hole In the second position communicated with the inside of the valve body, the throwing ball can be sealingly connected with the sliding sleeve and move the sliding sleeve from the first position to the second position. The invention realizes layered and quantitative steam injection of multi-oil layer units, and improves the steam injection efficiency of heavy oil wells.

Description

technical field [0001] The invention relates to the technical field of oil production, in particular to a multi-stage delayed steam injection pipe string. Background technique [0002] In the field of heavy oil steam huff and puff in oilfields, stratified steam injection technology is often used. This technology divides the whole well section into several steam injection units, and takes one or several groups of oil layer units with similar reservoir properties as a steam injection unit, and separates the oil layer units with packers to realize one-time steam injection. The pipe string injects steam into different oil layer units respectively, so as to adjust the steam suction profile of the oil layer unit and improve the effect of steam injection. These stratified steam injection technologies are mainly realized in two ways: First, the two-layer quantitative steam injection method of first injection (bottom) or first injection (upper) is realized by using the dispensing va...

AI Technical Summary

Problems solved by technology

These layered steam injection technologies are mainly realized in two ways: 1. Use the separate injection valve to realize the two-layer quantitative steam injection method of injecting upper (lower) or lower (upper) first, and the amount of steam injected in this way is better controlled , but limited to two layers of steam injection; 2. Use the throttle valve nozzle to realize simultaneous steam injection in heavy oil wells with two or more layers, because the size of the throttle valve nozzle is calculated based on the physical property parameters of the oil layer unit and steam injection parameters, etc. , the steam injection volume of each reservoir unit is not easy to control

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