高分辨率随钻电阻率成像测井在四川盆地碳酸盐岩储层的应用

Application of Microscope High Resolution LWD Resistivity Image Logging in Carbonate Reservoirs in Sichuan Basin

四川盆地碳酸盐岩储层发育层系多、埋藏深,储层物性普遍表现出低孔隙度、低渗透率的特征,储集空间纵横向非均质性强,构造复杂多变,水平井地质导向难度大。Microscope随钻电阻率成像测井仪提供多种探测深度的电阻率成像图形,有利于准确把握储层和构造特征,减少钻井风险。分析了四川盆地碳酸盐岩储层的特征和Microscope随钻电阻率成像测井仪的特点,提出了水平井地质导向中利用成像资料计算地层倾角的方法、判断井眼轨迹与地层空间关系的思路以及切入角的计算方法;提出了Microscope随钻电阻率成像图中裂缝、断层、溶蚀孔洞、溶蚀洞穴、井眼崩落等储层特征的识别方法。实例应用表明,Microscope高分辨率随钻电阻率成像能够有效地应用于地层倾角计算、构造分析和裂缝识别,强化了地质导向实时导向决策的准确性和及时性。

Many carbonate reservoirs in the Sichuan basin are multi-strata and deep burial depth. The physical properties of the reservoirs are characterized by low porosity, low permeability and strong heterogeneity in vertical and horizontaldirection. The structures are complicated and changeable. The Microscope LWD resistivity image logging tool provides the resistivity images with multiple depth of investigation, which helps to master the characteristics of the reservoirs accurately and reduce the risk while drilling. Analyzed are the characteristics of the carbonate reservoirs in the Sichuan basin and the characteristics of the Microscope LWD resistivity image logging tool. Proposed is a method to calculate the formation dip by using resistivity image logging data in real time geosteering of horizontal well, also the way to judge the spatial relationship between well path and the formation and the method to calculate the angle between them, and the way to identify the fractures, faults, emposieu, karst caves, and borehole wall caving. The Microscope LWD high resolution resistivity image logging tool indicates that it is effective to calculate the formation dip, analyze the structures, identify the fractures, providing accuracy and timeliness of the decision making for geosteering engineer.