致密砂岩裂缝填充识别及其测井响应特征 ———以鄂尔多斯盆地镇泾油田延长组为例.

The fractures in the Yanchang Formation of the Zhenjing oilfield in the Ordos Basin are dense sandstone fractures, and accurate identification of the fracture infill can help to better evaluate and develop the dense sandstone reservoir. Using core data, imaging logging data and conventional logging data of the Yanchang Formation, the fracture production, filling minerals and filling conditions were counted, and the main lithologies of the fractures were determined to be fine sandstone and siltstone, with calcite as the main filler. The logging response characteristics of filled and unfilled fractures were summarized by means of rendezvous plots and normal distributions, and the logging response differences between filled and unfilled fractures were compared to select fracture-sensitive logging parameters, constructing the curve change amplitude parameter and curve change rate parameter, and then constructing a comprehensive index identification method for fractures with and without filling. The results show that there is a significant difference between the response of induction logs to fracture filled and unfilled, some difference in the response of porosity logs to fracture filled and unfilled, and the least significant difference in the response of lithology logs. The response characteristics and identification method was applied to two wells, and the combined identification rate of fractured and unfilled wells was 76%. The results show that the response characteristics and identification method can provide new ideas for fracture filling evaluation in dense sandstones and improve the evaluation method for fractured dense sandstone reservoirs. [ABSTRACT FROM AUTHOR]