随钻方位伽马测井快速正演及定向井动态监测

Fast forward method for LWD azimuth Gamma-ray and dynamic monitoring of directional wells

钻定向井水平井已成为近些年钻井行业的热点.钻水平井过程中,地质导向起着关键作用,井眼轨迹的动态监测是其中的一个重要方面,包括沿钻进方向钻头距上下界面距离及距界面的垂直距离等,从而使井眼轨迹尽量保持在目的层中,最大限度的提高油气采收率.本文基于方位伽马测井的测量原理并结合几何特征,推导了一种随钻方位伽马测井的快速正演方法,该方法使正演计算中的复杂性大大降低,克服了利用蒙特卡罗方法正演模拟的困难.同时,本文利用方位伽马正演模拟曲线,对钻进过程中沿钻进方向上钻头到层界面距离及钻头距界面的垂直距离进行了反演计算.通过正演及反演结果对比,证明该方法在地质导向中应用的可行性.

Drilling in directional and horizontal wells in the drilling industry has become a hot spot in recent years. The geo-steering plays a key role in the process of drilling horizontal well. The dynamic monitoring of well trajectory is one of the important aspects,including the distance from the bit to the upper or lower interface along the drilling direction and the distance from the bit to the interfaces at the vertical distance,so that the well trajectory maintains the objective layer as far as possible,and oil and gas recovery rate is enhanced in maximum. In this paper,based on the measuring principle of azimuth gamma logging and combined geometric features,derived a drilling azimuth gamma ray logging the fast forward method. This method makes the complexity of forward computing greatly reduced,and overcome the difficulties of forward modeling Monte Carlo method. At the same time,this paper uses the azimuth gamma curve of forward simulation,the distance from bit to the interface process of drilling layer along the drilling direction and the vertical distance is inversion calculated. By comparing of forward and inversion results, proves that the feasibility of the method applicated in the geo-steering.