摘要：Two-stage PDC (Polycrystalline diamond compact) bit is a special drilling bit consisting of a small-diameter pilot and a large-diameter reamer. The unique rock-breaking structure is designed to improve drilling efficiency and reduce drilling costs in deep and abrasive formations. According to previous studies, the hydraulic structure of the two-stage PDC bit can significantly affect the drilling performance of removing cuttings near the bottom of the wellbore. Therefore, this research has proposed to achieve high efficiency of cuttings removal by optimizing the hydraulic structure. In this paper, the flow field at the bottom of the well near the two-stage PDC bit (Φ171.45 mm pilot + Φ215.9 mm reamer) has been numerically studied using the finite element method. As shown in the analysis results, both the flow rate of the pilot and the flow rate ratio of the pilot to the reamer increase significantly with the increase of the area ratio of the pilot nozzles to the total nozzles. The numerical data supports that the cuttings can be removed effectively from the bottom of the wellbore when the area ratio is between 0.75 and 0.80. Moreover, the cuttings can be removed effectively from the bottom of the wellbore when the mud viscosity is about 10 mPa s, the rate of penetration is between 4 and 8 m/h, the drill speed is 90 rpm, and the cuttings particle sizes is between 1 and 2 mm. Besides, increasing the pump rate can improve the cutting-carrying efficiency through the wellbore bottom. Field test results indicate that the average penetration rate of the optimized bit is increased by 47.17% and the footage of the optimized bit is increased by 95.40% compared to the equivalent formation in adjacent wells. This study can provide guidance for the optimal design of the hydraulic structure of such two-stage PDC bits. ? 2023 Elsevier B.V.

ISSN号：2949-8910

卷、期、页：卷230

发表日期：2023-11-01

影响因子：0.000000

收录情况：SCI（科学引文索引印刷版）,EI（工程索引）,SCIE（科学引文索引网络版）

发表期刊名称：Geoenergy Science and Engineering

参与作者：赵贺谦,Zhang, Bo

通讯作者：陈振良,李欣龙,于超

第一作者：史怀忠,黄中伟,赫文豪

论文类型：期刊论文

论文概要：陈振良,史怀忠,赵贺谦,黄中伟,赫文豪,李欣龙,于超,Zhang, Bo，Hydraulic parameters optimization of two-stage PDC bit in deep formation applications，Geoenergy Science and Engineering，2023，卷230

论文题目：Hydraulic parameters optimization of two-stage PDC bit in deep formation applications