塞平-1井所用单弯螺杆动力钻具自锁现象分析

ANALYZING SELF-LOCKING PHENOMENON OF PDM(POSITIVE DISPLALEMENT MOTOR) WITH BENT SUB IN SAIPING 1 WELL

王建军 张绍槐 狄勤丰

Wang Jianjun Zhang Shaohuai Di Qinfeng

西安石油学院

塞平-1并用1.25°单弯螺杆动力钻具造斜时,发生钻头加不上钻压的现象。通过理论分析,认为是扶正器自锁造成的。所谓扶正器自锁,就是扶正器相对的上下缘同时接触井壁,使所加的钻石完全被摩阻所抵消。扶正器在井眼内是否会发生自锁,主要取决于扶正器母线与井眼轴线的夹角是否大于自锁角。自锁角的大小主要取决于井眼直径、扶正器直径和长度。根据分析,缩短了扶正器长度,使扶正器外径以球状小斜角向本体过渡,结果克服了自锁,消除了钻头加不上钻压的现象,使塞平-1井顺利完成。

The one of troubles met during drilling Saiping 1 well is that the weight can’t forced on bit when using PDM with bent sub of 1.25 degree. Through theoretical analysis,it is believe that stabilizrs self-locking occurred during building up. The self-locking effect made the bit of weght was compietely off peted by friction and drag. The self-locking effect depend on the angle between the generatin llne of stabilizer and the akial line of borehole, if that angle larger than self - locking angle which depending on diameter of borehole and stabilirers and stabilizer’s length, According to the analyzing results, improving stabilizer’s profile and shorting its length made the self - locking effect be overcomed.

10.3969/j.issn.1000-7393.1995.02.003