川西须家河组地层PDC钻头结构参数优化及选型

Parameter Optimization and Selection of PDC Bits for Xujiahe Formation in Western Sichuan

川西深层须家河组气藏主力储层埋藏深、地质条件复杂,尤其是其地层硬度高、可钻性差,致使钻头选型困难,机械钻速低。为提高须家河组地层机械钻速,针对地层岩性特征,利用ABAQUS软件建立了切削齿破岩有限元模型,结合钻头设计理论优化了PDC钻头结构参数,确定出了适合须家河组地层的钻头冠部轮廓、切削齿、刀翼数和保径特征等主要结构参数,提出了PDC钻头选型的关键特征。在此基础上,优选出了9个型号PDC钻头,形成了须家河组地层钻头系列化选型方案:须5段—须3段地层宜选用攻击性强同时具有较强抗研磨性和抗冲击性的PDC钻头,须2段地层宜选用高抗研磨性兼顾吃入能力和抗冲击性的混合布齿钻头。现场应用表明,42只优选钻头平均进尺增加27.57%,钻速提高40.19%,实现了须家河组地层钻井提速新突破。

Xujiahe formation（T3 x^5 ）in Western Sichuan,is a deep foramtion and rich in natural gas. Usual cone bits and PDC bits wear quickly, so they are unsuitable for this formation due to tight rock, high content of quartz and high abrasiveness. So it is difficult to select the suitable bits with high penetration rate. In order to increase ROP and shorten drilling cycle, the finite element model of cutter and rock were created by ABAQUS based on the rock properties and bit design theory. The key bit structure characteris- tics for Xujiahe formation such as crown profile, cutter structure, wing numbers, hydraulic structure and stability are determined in line with the bit design thoery. PDC bits with high aggressiveness as well as antiabrasiveness and impact-resistance should be employed for formation T3 x^5-T3 x^3, hybrid cutter bits with high antiabrasiveness used for formation T3 x2. The application results indicate that selected bits increased footage by 27. 570% and improve ROP by 40.19% on average.