织金区块浅层煤层气J形大位移水平井钻井技术

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。 

Drilling Techniques in J-Shaped Extended Reach Horizontal Wells in Shallow Coal Bed Methane Reservoirs in the Zhijin Block

The 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 were applied to this block and analyzed. Then, drilling techniques in such wells 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, maximum deviation angle 97.6°, drilled coal seams 293.00 m and coal seam drilling rate 58.6%, which 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 techniques in J-shaped horizontal well could be successfully implemented in drilling wells in the Zhijin Block.