高温高压欠压实地层烃类检测方法研究:以莺歌海盆地东方X区为例

Hydrocarbon Detection for High Temperature and High Pressure Undercompacted Formation:A Case Study of Dongfang X District in Yinggehai Basin

莺歌海盆地中深层发育高温高压气藏,由于晚期快速沉降和快速沉积形成了巨厚的欠压实泥岩。受高温高压特殊成藏的影响,位于莺歌海盆地中央泥底辟构造带西南面的东方X区高温高压储层的地震反射特征十分复杂,欠压实泥岩的存在直接影响地震亮点,造成该区地震亮点指示作用失效。受高温高压复杂地质情况的影响,直接应用常规的烃类检测方法存在一定的问题,因此,首先分析了东方X区的岩石物理特性,发现欠压实效应是影响该区烃类检测技术的关键因素,继而利用欠压实条件下的叠前反演方法以及分频成像方法对东方X区进行了烃类检测。实例分析表明,本方法能够有效识别和预测出该区含气目标,为该区的进一步勘探开发布井提供一定的依据。

The high temperature and high pressure gas reservoirs are developed in the mid-deep strata of Yinggehai Basin,where the undercompacted formation is formed by rapid subsidence which caused huge undercompacted shale belt.Because of the influence of high temperature and high pressure reservoirs,the seismic reflection features are very complicated for the Dongfang X district located at the southwest of central mud diapir structure of Yinggehai Basin.Because of the undercompacted shale,the seismic bright spot information is invalid.Thus,the conventional hydrocarbon detection methods are not so effective in this district.To resolve this problem,we first conducted the rock physics analysis,and found that the undercompacted shale results in the difficulty of the gas detection technology in this area.Then,we use the prestack inversion for the undercompacted condition and frequency division imaging method to conduct the gas identification for the Dongfang X district.The results show that the methods proposed in this paper can identify and predict the gas target effectively,which is important for the following exploration and development to some extent.