南堡油田深部地层微心PDC钻头个性化设计与应用

Customized design of micro-core PDC bit and its application in the deep formations of Nanpu Oilfield

南堡油田东三、沙河街深部地层压实程度高,岩性复杂,泥岩胶结致密、研磨性强,可钻性差,导致常规PDC钻头机械钻速低。在深入分析该地层岩石力学性质基础上,开展了微心PDC钻头的研制。该钻头中心区域不布置切削齿,即采用无心轴式特殊结构,平内锥、宽冠顶、加长外锥设计,将更多的能量分配给承担更多工作的切削结构,提升切削齿的有效比钻压,提高破岩效率。现场应用十余井次,平均机械钻速8.7m/h,同比提高40%以上,单只钻头平均进尺470m,同比提高一倍以上。研究成果为南堡油田深部地层及其他类似地层钻井提速提供了新的思路和方法。

The deep formations in the third member of Dongying Formation and the Shahejie Formation in Nanpu Oilfield are characterized by high compaction degree, complex lithology, tight mudstone cementation, strong abrasiveness and poor drillability, which reduce the ROP of conventional PDC bit. Micro-core PDC bit was researched and developed after the rock mechanical properties of these deep formations were analyzed thoroughly. In the micro-core PDC bit, no cogging is arranged in the central zone, the special structure without mandrel is adopted and the design of flat inner cone, wide crest and extended outer cone is applied to distribute more energy to the cutting structure which undertakes more work, so as to increase cogging’s bit weight per unit area and improve the rock breaking efficiency. Micro-core PDC bit has been applied on site over 10 well times, presenting better application results. Its average ROP is 8.7 m/h, 40% higher than routine, and its average footage per bit is 470 m, 100% higher than routine. The research results provide the new method for the efficient development of deep formations in Nanpu Oilfield.