基于likelihood地震属性的致密气藏断裂预测——以四川盆地川西坳陷新场地区须二段为例

Prediction of fractures in tight gas reservoirs based on likelihood attribute —A case study of the 2 member of Xujiahe Formation in Xinchang area, Western Sichuan Depression, Sichuan Basin

李蒙 商晓飞 赵华伟 吴双 段太忠

Meng Li Xiaofei Shang Huawei Zhao Shuang Wu Taizhong Duan

传统地震断裂预测属性难以满足致密砂岩气藏勘探开发中对不同尺度断裂精细刻画的需求。将likelihood属性引入四川盆地须家河组致密砂岩气藏断裂识别，建立了基于likelihood属性及其衍生属性的地震断裂预测方法体系，提出基于Otsu阈值分割方法和成像测井约束下的断层发育区、裂缝带发育区和断裂欠发育区的空间分类，实现了对新场地区须家河组二段断裂精细预测。研究表明：经细化处理的likelihood属性可以体现最可能发育断裂的位置及其概率，断裂密度属性则有效反映了断裂发育强度特征，该属性对产量具有一定预测性。基于likelihood地震属性的断裂预测方法有效提升了新场地区须二段致密气藏断裂地震预测效果，对于其他裂缝型储层断裂预测具有一定借鉴意义。

Traditional fracture prediction methods based on seismic attributes fail to meet the demand for high-precision prediction of fractures of different scales in the exploration and development of tight sandstone gas reservoirs.By introducing the likelihood attribute into the identification of fractures in tight sandstone gas reservoirs in the Xujiahe Formation, Sichuan Basin, a seismic prediction method for fractures based on likelihood and derived attributes is established.The Otsu threshold segmentation method and constraints from image log interpretation are also employed to classify the reservoir space into fault zones, fracture zones and underdeveloped fracture zones and to perform a fine predication of fractures in the second member of Xujiahe Formation (Xu 2 member) in Xinchang area.Results show that the thinned likelihood attribute can reveal the most possible fracturing locations and probabilities.The fracture density reveals the fracturing intensity, which can be used to predict oil/gas production of a certain location.The fracture prediction based on likelihood attribute has effectively improved the seismic prediction accuracy of tight gas reservoirs in the Xu 2 member in the Xinchang area, and is of referential value to the prediction of other fractured reservoirs.

10.11743/ogg20200618