Research On Mechanism Of Intelligent Orientation Based On Off-line Programming Technology

With the energy shortage intensifying, the CBM (coal-bed methane) industry has been increasingly arousing every country’s attention all over the world. With the growing support on CBM industry, the industry is being bound to be leaps and bounds. In order to achieve reasonable CBM development and utilization, more and more high-tech are swarming into CBM industry. Among them, the Horizontal Directional Drilling (HDD) technology is one of the most common technologies in coal-bed methane mining. The intelligence level of directional drilling process and horizontal directional rig should be improved to increase the production of CBM.Based on the research and analysis of intelligence level of horizontal directional rig at home and abroad, combining with the characteristic of directional drilling engineering construction technology, this paper researches the mechanism of intelligent orientation drilling, develops the Off-line programming system of intelligent orientation for directional drilling, designs the control system of hydraulic correction drilling tool. The intelligent orientation of directional drilling is realized preliminary. Specific contents as follows:The Off-line programming system based on MFC technology is developed in this paper, which mainly consists of four modules:reading planned course module, arc fitting module, redrawing bore-path module, generating control program of drilling tool module. The CAD design file of drilling path is saved as DXF format. In the reading planned course module, the graphic data such as line and arc in DXF file are extracted, saved, optimized, and redrawn. The deflecting section of planned course is usually expressed with arc segment. However, the limitation of stiffness in bending of the drill stem determines that the drill stem can only bear minor deformations, so the arc segment of planned course should be fitting to several lines. Consequently, the deformations of deflecting section will be assigned to each drill stem on average to reduce deformations that each drill stem bears. In the arc fitting module, arc fitting method is deduced based on the theory of geometric, the starting point coordinates, ending point coordinates, inclination angle, and azimuth angle of each fitting line are calculated, the fitting error and the maximum permissible length of fitting line under condition of the maximum permissible error. In directional drilling engineering, due to the imbalance force that drill bit faced caused by underground complex environment, the actual bore-path will deviate from the ideal designed horizontal bore-path. The direction of the combined action in front of drill bit is discretional so the deviation direction and deviated amplitude can not be determined accurately. According to properties of bore-path curve, this paper figures out the possible maximum of deviated amplitude, figures out the deviation summation, determines the correction starting condition and correction path with the maximum permissible offset H, deduces the starting condition of deflecting drilling. In the redrawing bore-path module, the graphic data read from the reading planned course module are redrawn in Off-line programming system to prove accuracy of the reading planned course module, the graphic data after fitting are redrawn to compare with the graphic before fitting to prove accuracy of arc fitting method. In the generating control program of drilling tool module, taking hydraulic correction drilling tool as example, based on the research and analysis of overall process of control program of drilling tool, process of data acquisition, data processing, and data saving, process of single chip microcomputer A/D conversion, process of serial communication, process of drilling model selection, process of stepper motor driver and control, and process of superior computer communication, combining with the starting point coordinates, ending point coordinates, inclination angle, and azimuth angle of various control point, the control program of hydraulic correction drilling tool is generated in this module.The design of drilling tool control system is mainly circuit design, taking hydraulic correction drilling tool as example, including design of the single chip microcomputer minimum system, water pressure detecting module, drilling tool state detection module (including detection of azimuth angle, inclination angle and depth of drilling bore), stepper motor driver and control module, serial communication module, and power module. While deflecting drilling and hydraulic correction drilling, according to deviation value between actual azimuth angle and ideal value and deviation value between actual inclination angle and ideal value, the jet quadrant is determined, the stepper motor rotation angle is calculated, then the stepper motor is driven to rotate by a given angle for breakover of different jet holes to achieve deflecting drilling and hydraulic correction drilling.In conclusion, in order to improve the intelligence level of directional drilling engineering, this paper researches the mechanism of intelligent orientation drilling, develops Off-line programming system, designs the control system of hydraulic correction drilling tool. The intelligent orientation in directional drilling engineering is realized preliminary.