元坝陆相高压致密强研磨性地层钻井提速技术

ROP Improvement Technology for High-Pressure Terrestrial Tight Abrasive Formations in the Yuanba Gas Field

  • 摘要: 针对元坝气田陆相深部自流井组和须家河组地层岩性致密、硬度高、研磨性强,牙轮钻头进尺少、寿命短,以及综合效益低的问题,通过分析地层的可钻性、钻头的破岩原理,结合现场实钻情况优选高效钻头,并根据钻头与钻井工具的合理匹配原则优选合适的动力钻具,进行了"进口孕镶金刚石钻头+高速涡轮"复合钻井技术、"国产孕镶金刚石钻头+高效特殊螺杆"复合钻井技术和牙轮-PDC混合式钻头钻井技术现场试验。以钻头每单位进尺消耗的比能作为选择钻头的依据,并应用盈亏平衡理论对3种钻井技术进行了经济评价。现场试验结果表明:高压致密强研磨性地层首选"国产孕镶金刚石钻头+高效特殊螺杆"钻井技术;砾石含量高的珍珠冲组地层推荐采用"进口孕镶金刚石钻头+高速涡轮"复合钻井技术;砂泥岩互层较多的高压致密地层推荐采用牙轮-PDC混合式钻头钻井技术。经济评价结果表明,元坝气田应用"国产孕镶金刚石钻头+高效特殊螺杆"钻井技术的经济效益最高,其次是牙轮-PDC混合式钻头钻井技术,"进口孕镶金刚石钻头+高速涡轮"复合钻井技术最差。

     

    Abstract: Drilling footage and service life of cone bits were short and the comprehensive benefits were low in the Yuanba Gas Field,due to the fact that the Ziliujing and Xujiahe Formations in deep onshore regions are tight, hard and highly abrasive. Based on practical drilling situations, high-efficiency drill bits were selected through the analysis of the formations’ drillability and rock breaking principles. Appropriate dynamic drilling tools were selected according to the matching principle of drill bits and drilling tools.Then, field tests were conducted on the following three drill bits and tools combinations, including imported impregnated diamond bits and high-speed turbines, impregnated diamond bits and screws, and cones and PDC. Drill bits were selected on the basis of specific energy for unit footage consumption, and the three combinations were economically evaluated using breakeven analysis. Based on field test results, adoption was recommended for the homemade impregnated diamond bit and high-speed screw drilling for high-pressure and highly abrasive tight formations, and the impregnated diamond bit and high-speed turbo drilling for Zhenzhuchong Formation with high gravel content, and the cone and PDC drilling for high-pressure tight formations with more interbeds of sandstones and mudstones. Studies showed that the application of homemade impregnated diamond drill bit and high-speed screw drilling gave the best economic benefit contributions, followed by cone and PDC drilling followed by the imported impregnated diamond drill bit and high-speed turbo drilling.

     

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