Well pattern and method for improving fire flooding effect of thick-layer heavy oil reservoir

Abstract

The invention provides a well pattern and a method for improving fire flooding effect of a thick-layer heavy oil reservoir. The well pattern is disposed on an oil reservoir whose geological structure is a uniclinal structure. The well pattern is characterized in that the well pattern comprises a fire well row and at least a row of oil well. The fire well row is on the high part of the uniclinal structure. The fire wells in the fire well row are disposed along the high part of the uniclinal structure in sequence. The oil well rows are in the uniclinal structure, and are below the fire well row, and are arranged along a downdip direction of the uniclinal structure in sequence. The two adjacent well rows are arranged in parallel. The invention also provides a method for improving fire flooding effect of a thick-layer heavy oil reservoir. The method comprises: injecting gas to the fire well on the high part of the oil reservoir structure, igniting an ignition layer section, start fire flooding oil extraction; and extracting oil from the oil well on the downdip direction. The technical scheme can fully use altitude differences of the geological structure of the thick-layer heavy oil reservoir to achieve an objective of gravity drainage.

Description

Technical field [0001] The invention relates to a well pattern and a method for improving the fire flooding effect of thick heavy oil reservoirs, and belongs to the technical field of oil exploitation. Background technique [0002] Fire-burning oil layer is a thermal recovery method to improve oil recovery. It has low cost, low energy consumption, high oil displacement efficiency, wide adaptability, broad prospects, and can realize crude oil upgrading, but its oil displacement mechanism is complicated and has Steam flooding, hot water flooding, flue gas flooding and other displacement mechanisms are difficult to control during the implementation process, resulting in a low on-site success rate. Most of its successfully developed oil reservoirs are thin-layer oil reservoirs, and fire flooding of thick massive heavy oil reservoirs similar to high-rise oil fields is a brand new exploration and practice. Take the Lianhua oil layer of the Gao 3618 block in the Gaosheng area of ​​the ...

AI Technical Summary

Problems solved by technology

[0005] 1) The design of injection-production well pattern is unreasonable: row flooding well row is deployed in the waist of monocline structure, resulting in serious gas channeling in the updip direction, serious interference between two well rows, low air utilization rate, and slow effect of fire flooding;

[0006] 2) The design of the injection-production layer is unreasonable: the ignition layer of the fire well is in the middle or upper part, and the entire well section of the oil well produces, and the configuration relationship cannot achieve the purpose of gravity drainage;

[0007] 3) Unreasonable control technology: Lack of correct understanding of the mechanism of fire flooding gravity drainage and oil increase, lack of accurate judgment on the position of the front edge of the fire line, and the adoption of auxiliary huff-puff induction measures in a large range in the plane and in a large vertical well section. The damage of the wall is serious, resulting in the inability to form a stable displacement;

[0008] 4) Low gas injection rate: Due to the above well pattern design and layer design, it is bound to cause serious gas channeling, and the site had to adopt a plan to reduce the gas injection rate, which caused the front edge of the fire line to fail to maintain a stable push

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