Multistage delay steam injection string

Abstract

The invention provides a multistage delay steam injection string. The multistage delay steam injection string comprises a delay steam injection assembly and at least one layered steam injection assembly which are sequentially arranged from top to bottom, wherein the delay steam injection assembly comprises a delay steam injection valve and two upper packers, the delay steam injection valve comprises an inner barrel and an outer sleeve, a steam injection annulus is formed between the outer sleeve and the inner barrel, steam inlet holes communicating with the steam injection annulus is formed inthe side wall of the inner barrel, steam outlet holes communicating with the steam injection annulus is formed in the side wall of the outer sleeve, and the steam injection annulus is filled with gelcapable of blocking the steam inlet holes and the steam outlet holes; and the layered steam injection assembly comprises a layered steam injection valve and a lower packer, the layered steam injection valve comprises a valve body, a sliding sleeve and a throwing ball, a steam injection hole are formed in the side wall of the valve body, the sliding sleeve is provided with a first position for blocking the steam injection hole and a second position for communicating the steam injection hole with the interior of the valve body, and the throwing ball can be connected with the sliding sleeve in asealed mode and enables the sliding sleeve to move from the first position to the second position. According to the multistage delay steam injection string, layered quantitative steam injection of the multi-oil-layer unit is achieved, and the steam injection efficiency of a heavy oil well is improved.

Description

technical field [0001] The invention relates to the technical field of oil production engineering, in particular to a multi-stage delayed steam injection string. Background technique [0002] In the field of heavy oil steam huff and puff in oilfields, layered steam injection technology is often used. This technology is to divide the whole well section into several steam injection units, use a group or several groups of oil layer units with similar reservoir physical properties as a steam injection unit, and separate each oil layer unit with a packer to realize one steam injection The pipe string injects steam into different oil layer units separately, so as to adjust the steam absorption profile of the oil layer unit and improve the steam injection effect. 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) firs...

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

Images