深部地热钻探中硬塑性泥岩地层钻头应用研究

Research on bit application of hard plastic mudstone formation in deep geothermal drilling

摘要:

深部地热钻探中，通常会钻遇硬塑性泥岩，严重影响钻探施工效率。以雄安新区深部地热钻探工程实例为基础，深入分析硬塑性泥岩机械钻速低的原因，研究制定钻头的优化改进方案。实践应用证明：针对地层岩性特征设计的个性化PDC钻头配合螺杆钻具，可以有效提高硬塑性泥岩地层机械钻速；使用三棱形非平面复合片和三角形复合片等异形复合片可以有效提高PDC钻头的抗冲击能力、提高钻头在含砾石地层的使用寿命，同时也可以提高硬塑性泥岩地层机械钻速。探索出了一套适宜于深部地热钻探中硬塑性泥岩地层钻进的钻头应用方案。

Abstract:

Hard-plastic mudstone is usually encountered in deep geothermal drilling， which seriously affects the drilling efficiency. Based on the example of deep geothermal drilling project in Xiong^，an New Area，this paper deeply analyzes the reasons of low mechanical drilling rate in hard plastic mudstone， studies and forms the scheme of optimized and improved bit. The practical application proves that the mechanical drilling rate in hard plastic mudstone formation can be effectively improved by using the personalized PDC bit according to the lithology characteristics of the formation combined with the screw drilling tool. The impact resistance of PDC bit can be effectively improved by using special-shaped compacts such as triangular prismatic and triangular and the service life in gravelly formations can thereupon be increased， in addition， the mechanical drilling rate in hard plastic mudstone formation can also be increased. At last， a drill bit application scheme suitable for hard plastic mudstone formation in deep geothermal drilling is made.