Key Drilling Technology Of Coalbed Methane Multi-Branch Horizontal Well In Zhengzhuang Block

CBM is a kind of unconventional resources.In recent years,The application of multi-branch horizontal Wells in zhengzhuang block of qinshui basin has achieved good demonstration effect.Due to the complex geological conditions of coal seam in qinshui basin,many problems have been encountered in the actual drilling process,and many key technologies still need to be improved.Based on the well drilling,this paper studied the geo-steering technology of multi-branch horizontal wells in CBM and the optimization design and control technology of borehole trajectory.Based on the geological characteristics and many well drilling conditions in Zheng Zhuang block,this paper summarized and analyzed the geological characteristics of zhengzhuang block,as well as the difficulties in the drilling,such as lack of geological data of coal bed methane,complex formation conditions,large fluctuation of GR measurement value and many interference factors of drilling parameters.Combined with the geological characteristics of zhengzhuang block,the identification and judgment method of coalbed,the calculation method of formation dip Angle and the tracking and judgment method of coalbed drilling were optimized,which solved the key problem of accurately determining whether the bit was drilling in the coalbed or not.This paper researched on the near-bit lithology judgment technology and improved the coalbed drilling encounter rate with the analysis of drilling time,the gamma measurement value,the total hydrocarbon and the cuttings data.In order to improve the drilling efficiency and increase the rate of coalbed drilling,this paper mainly studied the optimization design and control technology of borehole trajectory and DHA optimization design scheme,forming a set of key technologies for multi-branch horizontal well in coalbed methane.The application of the these technologies has completed the production task of 7 wells in zhengzhuang.The total footage of coalbed reached 29082 m.The average drilling encounter rate of coalbed reached 93.77%.The average construction time of horizontal section was 31.86 days.The application of these technologies has made a good effect.