预测弯外壳导向钻具钻井造斜技术

预测弯外壳导向钻具钻井造斜率，合理控制井身轨迹，在定向钻井施工中非常重要，掌握导向钻具的结构参数和造斜能力，是定向钻井成败的重要因素。文中分析了单弯单稳定器导向钻具和同向双弯单稳定器导向钻具的钻井施工设计原理，指出为提高弯外壳导向钻具钻进时的“自由状态”造斜率，应增大弯角与缩短拐点至钻头底面距离，设计中应考虑钻头长度，增大拐点上部稳定器位置和建议把弯外壳单稳定器导向钻具设计成对称状态等。

PREDICTING THE BUILD-UP RATE OF STEERABLE DRILL TOOL WITH STABILLIZER AND BENT HOUSING

It is very important to predict the build-up rate of steerable motor with stabilizer and bent housing in order to control the wellbore trajectory rationally while drilling directional well of horizontal well.The key factor is to determine the build-up rate according to structural parameters of steering motor.For structural parameters of steering motor with single stabillzer and kick-off as well as that with single stabilizer and double kick-off,a new method of forecasting their build-up rate is presented.It is necessary to enlarge the bent angle and shorten the length from inflection point to the bottom of the bit in order to raise the build-up rate of steerable motor with bent bousing being in free status.The length of the bit should be considered when the motor will be designed.In the same time,It is suggested that the steerable motor should be designed to keep the stabilizer and the bit to be in symmetric state.