中文摘要：

塔里木盆地天山南探区为山前构造,钻井地质环境复杂,3 000m以浅地层含有大段砾石层,可钻性差。为此,在深入分析砾石层物性特征的基础上,有针对性地设计了适合于砾石层的Φ660.4和Φ444.5mm牙轮钻头和适合于微砾石层的Φ444.5mmPDC钻头。设计牙轮钻头时,通过优化钻头齿高、齿长及齿顶宽,调整布齿密度,及采用螺旋式双稳定掌背、滚滑复合轴承、中心喷嘴和中长喷嘴等方式,以增强钻头的攻击性,提高钻进效率和工作的稳定性;设计PDC钻头为7个喷嘴,采用耐磨性和抗冲击性较好的Φ19.0mm复合片和中低布齿密度、肩部双排齿结构、加强保径,以期在较低钻压下提高钻头的破岩效率。设计的3种钻头在天山南探区库2井一开、二开井段进行了现场试验,结果表明：与邻井实钻数据相比,Φ660.4 mm牙轮钻头钻速和单只钻头进尺分别提高84.62%和445.04%,Φ444.5mm牙轮钻头和PDC钻头的钻速分别提高46.15%和128.85%。在大北、克深两地区3口井的推广试验结果也表明,Φ660.4mm牙轮钻头可大幅提高机械钻速、节约钻时。综合分析各试验井数据认为,设计的3种钻头适合于在山前构造探区砾石层钻井,且提速提效明显。

英文摘要：

Abstract： South Tianshan exploration area in Tarim Basin is a piedmont structure,with very complex geological environment, where layers shallower than 3 000 m deep containing thick gravel layers are poor in drillability. On basis of analyzing physical property of gravel layer,C660.4 mm ＆ 4444. 5 mm roller bits suitable for gravel layers and 4444.5 mm PDC bit for microconglomerate layer have been designed. Drilling attackability,efficiency and stability of roller bit were enhanced by optimizing tooth projection and toe width,regulating tooth density, adopting screw wheel carrier, sliding and gliding complex bearing, center nozzle,and moderate length nozzle. PDC bit designed has 7 nozzles, and drilling efficiency was enhanced by adopting abrasion-proof and shock resistance compacts （419.0 mm）,mid-low density cogging distribution, double-row cogging on shoulder,and enhanced gauge. Bits designed have been tested in the first and second drilling sections of Well Ku2. Compared with adjacent well （Well Kul）, penetration speed and average footage of 4660. 4 mm roller bit rose by 84. 62% and 445.04%;penetration speed of 4444. 5 mm roller bit and 4444.5 mm PDC bit rose by 46.15% and 128.85%. The bits have also been tested in Dabei and Keshen area,and results showed that 4660. 4 mm roller bit could enhance penetration speed and save drilling time significantly. On basis of field test, the result showed that drilling bits designed were suitable for drilling in gravel laver in piedmont structure, with significant increase in penetration rate and drillina efficiency