考虑水平刮切作用的旋转钻井牙齿侵入规律

The law of tooth penetration during rotary drilling under horizontal cutting effect

冯福平 李清 吕媛媛 邢均

FENG Fuping LI Qing LYU Yuanyuan XING Jun

东北石油大学石油工程学院，黑龙江大庆　163318 吉林油田公司采油工艺研究院，吉林松原　138000 辽河油田公司勘探开发研究院，辽宁盘锦　124010 大庆油田设计院，黑龙江大庆　163712

Petroleum Engineering College, Northeast Petroleum University, Daqing 163318, China Petroleum Production Technology Research Institute of Jilin Oilfield Company, Songyuan 138000, China Research Institute of Petroleum Exploration and Development of Liaohe Oilfield Company, CNPC, Panjin 124010, China Design Institute of Daqing Oilfield Company, CNPC, Daqing 163712, China

考虑旋转钻井钻头牙齿对井底岩石产生的水平刮切作用，分析了井底岩石侵入系数的变化规律以及初次侵入破碎坑的形状，得出旋转钻井重复侵入时井底岩石的破碎过程以及载荷侵深曲线形态，进一步揭示了旋转钻井牙轮钻头破岩机理： 随着摩擦因数的增大，刃前岩石侵入系数线性降低，刃后岩石侵入系数线性增加；初次侵入时破碎坑为非对称的不规则形状， 岩石破碎体积比只考虑垂向压入作用时小，发生剪切破碎时所需的载荷低；刃前岩石发生剪切破碎以后，刃后岩石由于应力集中效应，达到剪切破碎时所需的整体载荷降低，存在水平刮切作用时岩石多次侵入剪切破碎更为容易；重复侵入时井底岩石剪切破碎频数是只考虑垂向压入作用时的两倍，剪切破碎时载荷下降的幅度降低。

This paper takes the horizontal cutting action of bit teeth on bottom hole rock into consideration, analyzes the varying law of bottom rock penetration coefficient and the shape of the initially penetrated broken pit, arrives at the bottom rock breaking process during repeated penetration by rotary drilling and the curve pattern of penetration depth of the load, and further reveals the rock breaking mechanism of roller bit in rotary drilling: with the increase of friction factor, the penetration coefficient of the rock before the blade is in linear decrease and the penetration coefficient of the rock after the blade is in linear increase after cutting. At initial penetration, the broken pit is asymmetric irregular shape, the volume of broken rock is smaller than when only vertical pushing-in effect is considered, and the load upon occurrence of shear breaking is low. After the rock before the blade is shear broken, for the rock after the blade, the overall load required by shear breaking decreases due to stress concentration, so shear breaking by multiple penetration into rock is easier at the presence of horizontal cutting effect. The frequency of shear breaking of bottom rock during repeated penetration is two times when only vertical pushing-in effect is considered, and the decrease rate of the load at shear breaking reduces.

10.13639/j.odpt.2015.03.001