Trenchless horizontal directional drilling trajectory design and control technology
|School||National University of Defense Science and Technology|
|Course||Measuring Technology and Instruments|
|Keywords||HDD Bore planning MWD Borehole condition monitoring Modifying|
With the rapid development of Trenchless Technology, Horizontal Directional Drilling (abbr. HDD) , the main method in Trenchless Technology, has become widely used for urban underground installation of new pipelines with its unique technical advantages. Supported by 863 - National High Technology Research and Development Program of China and Hunan Provincial Natural Science Foundation, the emphasis of this dissertation is put on the research of HDD bore planning and controlling methods on purpose to design a software system with the functions of automated bore planning, borehole condition monitoring, data processing and controlling in drilling. The main contents of this dissertation are as follows:1. With the establishment of global and local three-dimensional reference systems, geometric parameters that express the spatial position of any point of a bore path with respect to a reference system are defined. Then, drilling mechanism and control parameters are analyzed. Besides, the formula to calculate bore bend radius is derived out.2. A simple and universal model is presented with the study of general bore planning method of typical line-arc-line-arc-line bore shape. This fundamental model may not be applicable in the condition of several barriers underground. Therefore, two optimal design methods to solve this problem are put forward with the mathematic models. One designs the bore path on an inclined plane, the other divides the bore path into some segments and constructs them using a mixture of arcs and straight lines.3. The design idea of Measure While Drilling (abbr. MWD) system that is based on the philosophy of attitude measurement is analyzed. Two processing methods are carried out to translate the measured datum in the local reference system into the coordinate values in the global reference system, which makes it possible to compare the actual borehole with the planned one.4. A natural parameter model to forecast the direction of the actual borehole based on the local drilling database in practical situation is studied. At the same time, a soft landing design model is established to modify the bore path when it has deviated from the planned one.5. A HDD bore planning and monitoring software system is designed and realized with the key techniques discussed above. With the functions of automated bore planning,borehole condition monitoring, data processing and bore path modifying, the software will be a good guide in HDD engineering.