惠州区块深层火成岩地层钻井提速技术

南海东部惠州区块前古近系为火成岩地层，岩石强度高、地层可钻性差，导致钻速低、钻头进尺短和磨损严重。为提高火成岩地层钻井效率，通过地层岩性特点分析、钻头磨损评价，并根据测井数据开展了岩石力学分析，设计了高攻击力提速工具和钻头提高机械钻速，采用了强抗冲击性斧型齿和双排齿钻头增加进尺，并提高了钻头心部位置强度减轻磨损。钻井提速技术在惠州D井进行了成功应用，相比较于前期作业的惠州A井:在相同地层岩性的前古近系闪长岩和花岗岩段，钻头机械钻速分别提高了88%和69%，火成岩井段单只钻头平均进尺增加了31.5%，且出井钻头磨损较轻。该技术较好地解决了区域火成岩地层钻井效率低的难题，也为火成岩地层提速提效探索了解决方法。

ROP improvement technologies used in the deep igneous formation of Huizhou Block

The Pre-Paleogene in Huizhou block of eastern South China Sea is an igneous formation. Its rock strength is high and formation drillability is poor, which leads to low rate of penetration (ROP), short bit footage and serious wear. In order to improve the drilling efficiency in the igneous formation, this paper carried out rock mechanical analysis based on logging data, by analyzing stratigraphic and lithologic characteristics and evaluating bit wear situations. In addition, strong-aggression ROP improvement tool and bit were designed to improve the ROP, the high impact resistance bit with axed-shape teeth and the bit with double-row teeth were adopted to increase the footage, and the strength at the central part of the bit was increased to reduce the wear. ROP improvement technologies have been successfully applied in Well D of Huizhou Block. Compared with Well A of early stage in Huizhou Block, the bit ROP in Pre-Paleogene diorite and granite is increased by 88% and 69%, respectively, the average footage of each bit in the section of igneous rock is increased by 31.5% and the ascent bit is less worn. In conclusion, these technologies better solve the difficulty of low drilling efficiency in the igneous formation of Huizhou Block and explore the solution to ROP and efficiency improvement in igneous formations.