Geosteering technology and CBM horizontal well drilling without pilot hole
(2.Shanxi Lanyan Coalbed Methane Group Co.Ltd., Jincheng, Shanxi Province, China 048204)
【Abstract】In view of the difficulties in hole-forming of horizontal intervals in soft coal seams, low coal-seam drilling ratios, and need of pilot holes during deflecting drilling, the key technologies such as drilling-parameter optimization and anti-collapse drilling were put forward in the paper. Geosteering technology with multi-markers was used to realize timely layer identification and obtain a suitable targeting angle adaptive to the stratum dip, so as to realize one-time direct landing at the target. Geosteering and geometric steering were combined to finely control the wellbore trajectory of the horizontal interval to make the wellbore trajectory smooth. Three horizontal wells were drilled in Chengzhuang Coal Mine. The accumulative footage in the coal seam was 1 604.72 m. The coal-seam drilling ratio during drilling was 100%, and the final PE screen in the horizontal section had a total length of 1 366 m. The study can improve the drilling and completion technology of CBM horizontal wells, providing a new approach for low-cost and efficient CBM development.
【Keywords】 geosteering technology; horizontal well; well completion with screen pipes; marker bed; trajectory control; Chengzhuang coal mine; Qinshui basin;
(Translated by HAN R)
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