Concentric pipe layered steam injection system and method

Abstract

The invention discloses a concentric pipe layered steam injection system and a method. A cyclone and a phase mixing device are arranged in a steam inlet passage of a steam distributor of the concentric pipe layered steam injection system, the outlet end of the steam inlet passage is respectively connected with a first steam outlet passage and a second steam outlet through a dryness distribution chamber, an inner steam injection flow passage and an outer steam injection flow passage of a well opening device are respectively connected with a steam distributor through an inner steam injection opening and an outer steam injection opening, a concentric type layered steam injection pipe post is connected under the well opening device and realizes the steam injection to a first underground oil layer through the concentric steam distributor arranged on an outer steam injection pipe post, and the steam is injected to a second underground oil layer through an inner steam injection pipe post. The steam dryness from a boiler can be regulated, and in addition, the double-flow-passage layered steam injection is realized, so the accuracy of the steam injection quantity is ensured, simultaneously, certain compensation is provided for the thermal stress deformation generated by the pipe posts through high temperature in the well in the steam injection process, the steam injection effect is improved, and simultaneously, the occurrence of the condition of the pipe post damage is avoided.

Description

technical field [0001] The invention relates to a steam injection system and method, in particular to a concentric tube layered steam injection system and method applied to medium-deep heavy oil reservoirs. Background technique [0002] At present, Liaohe Oilfield is a multilayer heavy oil reservoir, and layered steam flooding technology is the main method for the development of heavy oil reservoirs. The method of steam injection for heavy oil production requires the use of a steam injection wellhead device and a concentric layered steam drive string connected below the steam injection wellhead device and located in the well to inject hot steam into different production layers in the well. [0003] Existing steam injection wellhead devices generally include a large four-way, an outer pipe small four-way, an inner pipe small four-way and a test gate valve. Among them, the side end of the large cross is fixedly installed with a casing gate valve, the top of the large cross is...

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Problems solved by technology

When this kind of concentric layered steam injection string is used for layered steam injection, since the inner steam injection pipe and the heat insulation pipe are fixedly connected together through the inner packer, the downhole pipe string will be affected by the heated steam to a certain extent. Due to the relative movement between the inner steam injection pipe and the heat insulation pipe, the thermal stress generated by the inner steam injection pipe and the heat insulation pipe cannot be released, which affects the steam injection effect

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