塔河油田奥陶系缝洞充填序列及其测井响应

碳酸盐岩缝洞充填对缝洞型储集层有重要影响,准确识别缝洞充填物类型,建立充填模式,有利于更好地识别与评价缝洞型储集层的发育情况。通过观察岩心,将缝洞充填物划分为砂泥质充填物、角砾岩充填物、化学充填物和未充填;利用测井信息标定各类充填物的测井响应特征,基于岩溶形成的主控因素将缝洞充填体分为地下暗河型、断控岩溶型及表层岩溶型3种类型,并建立充填模式。在此基础上,结合岩心观察,归纳不同充填模式的一般充填序列及其测井响应特征,发现地下暗河型更易钻遇大溶洞,断控岩溶型有利于油气的运移,表层岩溶型则多发育溶蚀孔洞。

Ordovician Fracture-Cavity Filling Sequence and Its Logging Responses in Tahe Oilfield

Fracture-cavity filling in carbonate rocks has an important influence on fracture-cavity reservoirs. Accurately identifying the types of fracture-cavity fillings and establishing filling patterns are conducive to better identifying and evaluating the development situations of fracture-cavity reservoirs. By observing the core, the fracture-cavity fillings can be divided into sand-shale fillings, breccia fillings, chemical fillings and empty filling. The logging response characteristics of various fillings are calibrated by using logging information. Based on the main controlling factors of karst forming, the fracture-cavity fillings can be divided into three types, namely underground river type, fault-controlled karst type, and surface karst type, and then establish filling mode. On this basis, combined with core observations, the general filling sequence of different filling modes and its logging responses are summarized. It is found that large karst caves are easier to be drilled in the fillings of the underground river type, the fillings of fault-controlled karst type is conducive to migration of oil and gas, and dissolved cavities are developed in the fillings of surface karst type.