Dissolving cavity groove-construction method for tertiary-system stratum ultra-deep connection brine mining well

Abstract

The invention relates to the technical field of bittern production, in particular to a dissolving cavity groove-construction method for a tertiary-system stratum ultra-deep connection brine mining well. The dissolving cavity groove-construction method for the tertiary-system stratum ultra-deep connection brine mining well comprises the following steps of: establishing an ultra-deep connection wellgroup; injecting fresh water mud, and establishing well group circulation; gradually lowering the concentration of the fresh water mud, meanwhile, regulating a circulation displacement of the fresh water mud, and carrying out dissolving cavity groove construction; and when the concentration of the fresh water mud is lowered to a preset numerical value, replacing the fresh water mud with clear water, and carrying out dissolved brine circulation, and carrying out normal brine mining work. When the method provided by the embodiment of the invention is adopted, well bottom effective pressure canbe improved, and stratum stress is gradually released to avoid a situation that a stratum suddenly loses stability and collapses on a large area to block a channel. Meanwhile, salt bed creepage and hole shrinkage can be alleviated so as to gradually enlarge a horizontal channel, transition from mud to clear water is successfully finished during a groove-construction period of the ultra-deep connection well group, and therefore, the normal brine mining of the ultra-deep connection well group is successfully realized.

Description

technical field [0001] The invention relates to the technical field of brine production, in particular to a solution cavity construction method for ultra-deep connected brine production wells in Tertiary strata. Background technique [0002] Ultra-deep brine mining wells refer to brine mining wells with a depth greater than 3,500 meters. Brine mining wells of this depth often have ultra-high pressure and ultra-high temperature (140°), especially in Tertiary strata. The geological conditions It is more complex and the pressure of the overlying strata is high. The conventional shallow well trench construction technology in the prior art cannot achieve the purpose of solution cavity expansion at all. If the existing technology is used to expand the solution cavity with clean water, the clean water cannot be balanced The pressure of the overlying strata on the stratum can easily lead to the blockage of the circulation channel, resulting in the failure of the project. [0003] T...

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Problems solved by technology

[0002] Ultra-deep brine mining wells refer to brine mining wells with a depth greater than 3,500 meters. Brine mining wells of this depth often have ultra-high pressure and ultra-high temperature (140°), especially in Tertiary strata. The geological conditions It is more complex and the pressure of the overlying strata is high. The conventional shallow well trench con

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