随钻方位伽马成像测井在鄂尔多斯盆地H井区水平井地质导向中的应用

随钻方位伽马成像测井是水平井地质导向技术的重要组成部分,与常规随钻伽马测井相比,方位伽马成像测井仪利用多个伽马探测器,将带有方位信息的测量数据上传到地面,精确指导井眼轨迹调整,确保维持在目的层的有利位置钻进。根据上下伽马曲线和成像图的8个响应特征将常见的水平井井眼轨迹与地层接触关系划分为简单模式和复合模式,简单模式细分为5大类8种情形,同时给出了不同井眼轨迹与地层接触关系下地层视倾角的计算方法。在鄂尔多斯盆地H井区的应用表明,随钻方位伽马成像测井可提供及时且准确的导向建议,显著提高了钻井效率,长水平段水平井的储层钻遇率超过94%,达到提高单井产量和建产效率的目标。

Application of Azimuthal Gamma Ray Imaging LWD to Geosteering in Horizontal Wells of H Area, Ordos Basin

Azimuthal gamma ray imaging LWD is an important part of geosteering technology for horizontal wells. Compared with conventional gamma ray LWD tools, the azimuthal gamma ray imaging LWD tool can guide the adjustment of the borehole trajectory accurately. It also ensures that the drilling is maintained in a favorable position of the target layer by using multiple gamma detectors. The measurement data with azimuthal information is uploaded back to the surface. According to the eight response characteristics of the upper and lower gamma curves and the imaging maps, the common relationships between horizontal well trajectory and formation are divided into simple modes and composite modes, and the simple modes can be subdivided into five categories and eight sub-modes. The calculation method of the apparent dip of the formation under different relationships between well trajectory and formation is given. The application in H area of the Ordos Basin shows that the azimuthal gamma ray imaging LWD can provide timely and accurate steering suggestions, and improve the drilling efficiency significantly. The reservoir penetration rate of horizontal wells with long horizontal sections exceeds 94%, which achieves the goal of increasing single well production.