1. State Key Laboratory of Coal and CBM Co-mining,Jincheng 048012,China; 2. Shanxi Lanyan Coalbed Methane Engineering Research Co. ,Ltd. ,Jincheng 048000,China; 3. Yi’an Lanyan Coal and Coalbed Methane Co-mining Technology Co. ,Ltd. ,Taiyuan 030031, China; 4. Faculty of Earth Resources,China University of Geosciences (Wuhan),Wuhan 430074,China

China is rich in deep coalbed methane (CBM) resource,which has gradually entered the stage of exploration and development. However,the number of cost-effective CBM wells is relatively small. Drilling technology is the dominate factor restricting the productivity of CBM horizontal well. On the one hand,the track of landing well section is required to be smooth,contributing to the match between landing horizon,angle and formation parameters,which avoids high failure rate of drainage equipment and discontinuous drainage. On the other hand,the drilling intercept rate of coal seam in horizontal section must be as high as possible to ensure sufficient gas supply. Therefore,on the basis of the geo-steering experience of deep CBM horizontal wells in the early stage,this study puts forward the geo-steering technology which integrates well log,orientation and mud logging technology to optimize the well trajectory and improve the landing accuracy of target and the coal seam drilling intercept rate in the horizontal section. The main process of this technology is as follows:first establishing the geological model of the target layer according to the limited drilling and seismic data in the early stage,then obtaining the response value of the logging parameters of the drilled formation through the vertical well section during the implementation of the drilling project,comparing the directional and logging parameters in real time when drilling in the horizontal section,and correcting the gamma while drilling in time,then using the GeoWorks software to carry out the layer comparison and division,finally establishing the dynamic geological model to adjust and predict the follow-up well trajectory. Through the application of well HL-U-04 in Hengling block of Qinshui Basin,the technology has achieved a good application result. The construction period was shortened by 30% ,and the coal seam drilling intercept rate was increased by 24. 47% . After the completion of drilling,the fracturing casing pressure of coiled tubing was stable at 35 MPa with the displacement of 5. 7 m3/ min,which achieved the effect of reservoir reconstruction. During production,the daily production of the well was stable at about 1 000 m3 at the initial stage of production. Therefore,the integrated geo-steering technology of logging and orientation improves the accuracy and efficiency of horizontal well drilling technology.

SHEN Penglei,BAI Jianping,LI Guishan,et al. Integrated geo-steering technology of logging and orientation in deep coalbed methane horizontal well[J]. Journal of China Coal Society,2020,45(7):2491-2499.