Research On Measurement-while-drilling Technology In Underground Mine And Data Processing Method Of Borehole Trajectory

With the rapid development of directional drilling technology, due to its technical advantages MWD technology has been widely applied not only in oil drilling and trenchless field, but also progressively extended into coal mine safety field recent years, and has plaied more and more important role in drilling surface and underground gas drainage boreholes. On the basis of the project "Development of underground horizontal directional drilling rig and its matching technology ", a major industrial technical special project of National Development and Reform Commission, aiming at development of mine MWD directional drilling system in China, in combination with charecteristics of underground directional drilling, the paper carried out study mainly on description of borehole trajectory, MWD method, signal transmission technique and data processiong of borehole trajectory. The study included maily the following aspects:1. In combination with characteristics of directional drilling in underground coal mines, we systematically proposed description method for related parameters and shape characterizing spatial position of trajectory of underground horizontal directional boreholes. Calculation methods for coordinate of trajectory of five kinds of surface boreholes were transformed and optimized, and were successfully applied to calculate trajectory of underground horizontal directional boreholes, providing a basis for design and trajectory description of future underground directional boreholes.2. In combination with field requirements and from the view of drilling technology, we proposed the design and flowchart of MWD system software, used the three elements of borehole trajectory,elevation of roof and floor of coal seam to design borehole trajectory, and constructed mathematical model. During drilling simultaneous display od designed trajectory and measured trajectory was realized, providing convinience for knowing the relative position of borehole from time to time.3. On the basis of analysis of field requirements, we proposed three new methods for data processing of borehole trajectory. Based on Excel platform, programme for calculation of trajectory parameters and plotting of trajectory diagraphs was established. The programme could not only calculate trajectory parameters,but also make two dimensional diagraph display. With the aid of secondary development platform Auto CAD VBA, the programme for plotting borehole trajectory diagraph Excel-CAD was developed, providing convinience for composition of measured trajectory and designed trajectory. Using engineering-based concept VC ++6.0, we developed software for design and analysis of borehole trajectory, realized two dimensional and three dimensional display of borehole trajectory.4. In combination with field industrial test, three methods for borehole trajectory data processing was applied to process MWD data and diplay trajectory diagraph of directional borehole set at drilling site 2 at face 534 in Ruqigou mine. The results of synthetic processing plaied a guiding role in controlling borehole trajectory, on the same time created conditions for visualized design, informational operation and multiple diagraph linking of directional boreholes in the future.