资阳东峰场须五段储层异常高压成因分析

Analysis of High-Pressure Anomalies in the Xuwu Formation Reservoirs of Dongfeng Field Structure in the Ziyang Region

摘要: 四川盆地须五段地层在盆地内广泛分布，厚度自西向东逐渐减薄，最厚可达750 m，最薄处普遍小于50 m。盆地内部大部分区域须五段下部地层岩性整体以泥岩夹薄层状粉砂岩、砂岩为主。东峰场构造须家河组五段沉积4套叠置砂体，多口井压恢测井解释发现地层压力系数变化较大，总体在1.3左右，但部分井压力系数达到1.6以上，最高可达1.7，异常高压是油气勘探与开发中的重要地质现象，对油气藏的形成与保存、钻井作业安全及油气资源开发策略等方面具有重要影响，其形成机理复杂多样，包括欠压实作用、烃类生成、构造应力挤压等多种因素。可通过钻井液性能变化、工程参数变化及地层压力测试等方法可以判断地层压力状态。因此，深入研究地层异常高压的形成机理及其特征，对于指导油气勘探与开发具有重要意义。

Abstract: The Xuwu Formation in the Sichuan Basin is widely distributed within the basin, with its thickness gradually decreasing from west to east. The maximum thickness can reach up to 750 meters, while the minimum thickness is generally less than 50 meters. In most areas of the basin, the lithology of the lower part of the Xuwu Formation is predominantly composed of shale interbedded with thin layers of siltstone and sandstone. In the Dongfeng Field structure, the Xuwu Formation consists of five sedimentary packages of stacked sandbodies. Well logging and pressure recovery tests have revealed significant variations in formation pressure coefficients, with an overall average of around 1.3. However, in some wells, the pressure coefficient exceeds 1.6, with the highest value reaching 1.7. Abnormal high pressure is an important geological phenomenon in oil and gas exploration and development. It has significant impacts on the formation and preservation of hydrocarbon reservoirs, drilling operation safety, and the development strategies for oil and gas resources. The formation mechanisms of abnormal high pressure are complex and diverse, including undercompaction, hydrocarbon generation, and tectonic stress compression, among other factors. The formation pressure state can be determined through methods such as changes in drilling fluid properties, variations in engineering parameters, and formation pressure testing. Therefore, in-depth research on the formation mechanisms and characteristics of abnormal high pressure in formations is of great significance for guiding oil and gas exploration and development.