Development And Experimental Study On Electric Melting Pipe Device Of Simulation Experiment Of Protecting Borehole Wall

In order to prevent well bore instability collapse and other accidents, it needs to take such as casing, cement plugging, using high-quality drilling fluid, expandable casing and other measures in drilling process. But these methods have their limitations. In order to make the wall reinforcement fast, safe, efficient, it is necessary to study a new protective method. The hot melt drilling technology principle is the foundation, we proposed a new type of method that electric melting pipe protecting borehole wall blasting. According to this new method, designing the scheme of a set of electric melting sleeve simulation experiment device. Through laboratory experiments, the following results are obtained.First, briefly introducing the origin and research status of subterrene drilling technology, and explain the source of electric melting pipe protecting borehole wall blasting method. Summarize the research situation of existing wall technology at home and abroad, and then discusses the key technologies of electric melting pipe protecting borehole wall blasting method. The design of the key lies in the choice of large power heating elements, the choice of low melting point wall material and the design of the related process parameters.Based on the key technology of electric melting pipe protecting borehole wall blasting, this paper designs a simulation experiment device indoor. It mainly consists of (1) power supply system:in order to voltage to the heating element to provide a0-100V adjustable, designed by the laboratory of380V three-phase alternating current transformer and then connected to the35KVA SCR power regulator power supply structure;(2) borehole simulation device:indoor experimental simulation is similar to the well hole eye, designed for the two segment can be split shaft, with earth and stone to pile hole, simulation of wellbore;(3) the slow rotation mechanism:in order to verify the electrothermal melting forming short rotation effect on the wall effect;(4) the lifting mechanism:to make the electric heating melt forming short timely raised or lowered;(5) measurement system:in order to timely detection and record the related data in the experiment, as to speed, physical strength, electrothermal melting forming short temperature etc.. These five parts constitute the main experimental device.The electric melting sleeve simulation experiment device for processing the physical and assembly operation, through the measure of the power supply stability, verified the reliability and feasibility of the design. Design of simulation experiments respectively with wall, clay, sand, gravel and with rocks to simulate wellbore, they were used to experiment, draw the conclusion:the rotary speed and the speed should be reduced as much as possible in a certain range; the heating time should be able to guarantee the formation of liquid film fully between melt and forming short shell; electric heating weld pipe protecting borehole wall blasting method is feasible, casing wall after various aspects strength meet the selection and matching requirements and casing strength depends on the wall material; wall heat forming short casing mainly concentrated in the range of5cm, conducive to the efficient use of heat.