Hollow layering steam injecting system

Abstract

The invention discloses a hollow layering steam injecting system. An heat preservation oil pipe is connected below a well head device; the lower end of the heat preservation oil pipe is connected with a telescopic pipe; the lower end of the telescopic pipe is connected with a steam distributing pipe column part; the steam distributing pipe column part comprises an anchor, an oil pipe, packers, an oil pipe releaser and a hollow steam injecting valve; the anchor is positioned at the uppermost end of the steam distributing pipe column part; the lower end of the telescopic pipe is connected with the anchor; in the steam distributing pipe column part, a top packer is arranged above a top oil layer, and is connected to the lower end of the anchor; a middle packer is arranged in a gap of adjacent two oil layers; the oil pipe, the hollow steam injecting valve and the oil pipe releaser are connected between adjacent two packers; and the lower end of the middle packer above a lowermost oil layer is connected with the oil pipe, the hollow steam injecting valve, the oil pipe and a plug. The hollow layering steam injecting system can preferably release thermal stress of a pipe column, is more accurate and effective in steam injecting effect, prevents the steam injecting valve from scaling to block a steam injecting channel, and increases the inner diameter of the pipe column for convenient dropping and fishing.

Description

technical field [0001] The invention relates to a layered steam flooding system used in heavy oil production, in particular to a hollow layered steam injection system. Background technique [0002] With the gradual increase of steam huff and puff cycle in heavy oil reservoirs in Liaohe Oilfield, the effect of steam huff and puff is getting worse gradually, and the requirement of changing the development mode is becoming more and more prominent. For multi-layer heavy oil reservoirs in Liaohe Oilfield, the large-scale application of layered steam flooding technology provides a guarantee for the production of crude oil in the block, but the pilot test and field construction show that the layered steam flooding technology has yet to In order to improve the performance of steam flooding in Class II and III heavy oil reservoirs (common classification standards in the field of heavy oil), it is necessary to improve and improve the supporting fishing technology urgently. mining eff...

AI Technical Summary

Problems solved by technology

Secondly, due to the influence of the inclination angle during the drilling process, the steam distribution valve of the steam injection string is not completely vertical in the well, so there will be a locking phenomenon during the fishing process, resulting in that even if the fishing tool catches the steam injection The valve cannot be salvaged, which leads to the failure of salvage and the inability to adjust the steam injection volume of each layer

At the same time, since the upper and lower packers seal the annulus between the tubing and the casing, the positions of the two packers are fixed, and the thermal stress of the tubing between the upper and lower packers cannot be released during steam injection, which may easily cause deformation of the tubing and seriously In some cases, the packer will fail, causing steam leakage and affecting the accuracy of steam injection.

In addition, the wellhead required by the existing steam injection string is large in volume, high in the wellhead, and complex in structure, which affects the transmission efficiency on the one hand, and on the other hand, the steam is transported in the wellhead for a long distance, and the steam is easy to leak

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