织金区块浅层煤层气 J形大位移水平井钻井技术

摘要

T he drilling phase for in the Zhijin coalbed methane (CBM ) block is characterized by a low drilling rate for the coal seam ,a difficult‐to‐protect reservoir ,high cost of drilling horizontal connected wells ,and a low economic benefit .In order to solve these problems ,the technical difficulties of J‐shaped horizontal drilling w ere applied to this block and analyzed .T hen ,drilling techniques in such w ells drilling in shallow CMB reservoirs were studied from well track optimization ,casing program optimization and borehole trajectory control .Finally ,the process underwent a practical test in the Zhiping 1 Well .This well was drilled smoothly with horizontal lateral of 500 .00 m ,horizontal displacement 818 .98 m ,maxi‐mum deviation angle 97 .6° ,drilled coal seams 293 .00 m and coal seam drilling rate 58 .6% ,w hich is much higher than that of horizontal connected wells (43 .6% ) .In addition ,the cost to drill the well was only 58% of that of U‐shaped horizontal connected wells .The positive results indicated that these drilling tech‐niques in J‐shaped horizontal well could be successfully implemented in drilling wells in the Zhijin Block .%织金煤层气区块存在煤层钻遇率低、储层保护难度大、水平连通井钻井成本高、经济收益低等问题，为此，在分析该区块J形水平井工程技术难点的基础上，从井眼轨道优化设计、井身结构优化设计、井眼轨迹控制技术等方面进行了浅层煤层气J形大位移水平井钻井技术研究，并在织平1井进行了试验。织平1井顺利完钻，水平段长500．00 m ，水平位移818．98 m ，最大井斜角97．6°，钻遇煤层293．00 m ，煤层钻遇率58．6％，远高于水平连通井的煤层钻遇率（43．6％），且钻井成本为U形水平连通井的58％。这表明，采用J形水平井钻井技术可以解决织金煤层气区块存在的问题，可以在织金区块推广应用。