一种异常高压形成机制判别方法与应用

系统总结异常高压形成机制,分析岩石沉积压实过程的力学关系,在此基础上对异常高压形成机制进行分类。根据地层加载和卸载时的不同测井参数响应特征以及构造挤压环境下的典型构造地质特征,建立一种异常高压形成机制判别方法。收集南海莺琼盆地一口高温高压井的测井数据,利用该方法对该井进行分析。结果表明:该方法能够准确判别区分出欠压实、构造挤压和流体膨胀等异常高压形成机制,进而可以为优选地层压力计算模型提供依据;该井3.45 km以下地层存在流体膨胀机制造成的异常高压;利用判别结果选择的压力计算模型能够有效提高地层压力的计算精度。

Investigation and application of a discrimination method for abnormal high formation pressure forming mechanism

The forming mechanisms of abnormally high formation pore pressure were systematically summarized and the mechanical relation in the sedimentary compaction process was analyzed.The mechanisms of abnormally high formation pore pressure were categorized.A method to discriminate the forming mechanisms of abnormally high pressure was proposed according to the different logging response of the formation’s loading and unloading procedure and the geological characteristics of typical structure in tectonic compression environments.The logging data of one well with high temperature and high pressure in Yingqiong Basin at South China Sea were collected.The results show that the mechanisms of under-compaction,tectonic compression and fluid expansion can be determined by this method.A reasonable model to calculate the pore pressure of this well can be selected.There is abnormal high pressure over 3.45 km deep zone,which is caused by fluid expansion mechanism.The precision of pore pressure calculation is significantly improved by using the selected pressure calculation model.