A method for replacing mud and expanding the diameter of horizontal butt joint wells in ultra-deep salt mines

Abstract

The invention discloses an ultra-deep salt mine horizontal docking well slurry replacing and diameter expanding method. The method comprises following steps: a cavity is constructed in a salt bed of a target well through conventional convection in advance; a horizontal well communicated with the cavity is drilled, well drilling circulation solution is replaced by groove expansion slurry and well drilling circulation solution is replaced by segment; drilling tools are lifted out, the groove expansion slurry is continuously circulated in the well, clear water is continuously added to the circulated groove expansion slurry as the horizontal hole section is dissolved and expanded, and the pressure of the injected groove expansion slurry is increased, the specific weight of the groove expansion slurry is gradually reduced and finally clear water circulation is completely involved in brine extraction production. By means of the invention, pressure in the hole can be effectively maintained and collapse of the hole is prevented, and the hole wall stone salt can be effectively dissolved to gradually enlarge the horizontal section diameter, and the insoluble matter is washed and stored in the pre-built cavity by the slotted slurry without influencing circulation. It is simple to prepare the circulating groove expansion slurry and convenient for operation and control; pore wall stress changes stably, pore diameter develops evenly; the method is safe and reliable, and low in cost.

Description

technical field [0001] The invention relates to the field of salt mine mining, in particular to a method for dissolving and expanding the diameter of an ultra-deep salt mine horizontal butt joint well for mud and salt layer hole sections. Background technique [0002] During the development of salt mines in the Yellow River Delta, the depth of the salt mines exceeds 4200m, which is the deepest horizontal butt joint well for mining salt mines. During the construction process, after the successful butt joint connection of the horizontal wells, the borehole diameter shrinkage occurred during the mud process. A serious collapse hole buried drilling accident occurred. In view of these problems, it is very necessary to study a new mud replacement process. [0003] Generally, during the drilling process of such deep horizontal sections of salt layers, the drilling fluid with a specific gravity of 1.6-1.9 and a salt content close to saturation is used to ensure smooth drilling. Af...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to provide a method for replacing mud and expanding the diameter of horizontally connected wells in ultra-deep salt mines. Through specially formulated technological measures and the preparation of suitable gravity expansion fluid, the stress on the wall of the borehole can be adjusted within the rock salt elastic limit and Dissolve rock salt to solve problems such as borehole collapse, buried drill and stuck drill, and borehole creep shrinkage and plugging accidents

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