基于X射线荧光元素录井的深层页岩气精准地质导向技术

川南威荣页岩气田深层页岩气水平井钻井过程中，准确卡取标志层、识别钻头位置和判断钻头穿行状态的难度很大。为此，利用X射线荧光（XRF）元素录井数据建立了三端元图版、元素交会图版和元素三维显示图版，以及岩石密度、含气量等评价参数的定量计算模型。根据三端元图版卡取入窗前的重要标志层，利用元素交会图版指导水平井准确入窗，通过元素三维显示图版判别水平段钻头穿行状态，利用岩石密度、含气量等评价参数指导水平井井眼轨道优化，形成了基于X射线荧光元素录井的精准判识目的层及钻头穿行状态的地质导向技术。该技术在威荣页岩气田18口页岩气水平井进行了应用，靶体平均钻遇率达到98.06%。研究表明，基于X射线荧光元素录井的精准地质导向技术能够准确卡取标志层、识别钻头位置和判断钻头穿行状态，提高优质储层的钻遇率。 

Accurate Geosteering Technology for Deep Shale Gas Based on XRF Element Mud Logging

During drilling the deep shale gas horizontal wells in the Weirong Shale Gas Field in southern Sichuan, it is very difficult to accurately identify the marker bed, determine the bit position and judge the penetrating state of bit. To solve this problem, the X-ray fluorescence (XRF) element mud logging data was used to establish a three-terminal chart, an element intersection chart and a three-dimensional element display chart, as well as a quantitative calculation model of evaluation parameters such as rock density and gas content. The Geosteering Technology has been formed by such principle, including that fact that a three-terminal chart was used to identify the key marker beds before window-entering, the element intersection chart was used to guide the accurate window-entering of horizontal well, the three-dimensional element display chart was used to determine the penetration of the bit in a horizontal section, and the shale density and gas content etc., were used to guide the optimization of horizontal wellbore trajectory. This technology has been applied in 18 horizontal shale gas wells in the Weirong Shale Gas Field, with the average drilling rate of the target up to 98.06%. Research results showed that the technology could improve the rate of encountering high-quality reservoirs by accurately identifying the marker bed, determining the bit position and judging the penetrating state of the bit.