石油实验地质2026，Vol.48Issue(2)：375-385,11.DOI:10.11781/sysydz2026020375
东海盆地西湖凹陷平湖斜坡带复合成因超压判别及定量评价
Identification and quantitative evaluation of overpressure with a composite origin in Pinghu slope belt,Xihu Sag,East China Sea Basin
摘要
Abstract
Formation pressure is a key factor controlling hydrocarbon migration and accumulation.Overpressure is widely developed in the Pinghu slope belt of the Xihu Sag in the East China Sea Basin,exhibiting complex distribu-tion patterns that make formation pressure interpretation and evaluation difficult.To accurately identify the origin of overpressure and achieve quantitative assessment,this study comprehensively employed the mudstone compac-tion curve method,the acoustic velocity-vertical effective stress chart method,and the acoustic velocity-density chart method to identify overpressure in this area as a composite result of undercompaction and fluid expansion.On this basis,an evaluation system combining the equivalent depth(ED)method and the sound velocity rebound(SVR)method newly developed by our research team was adopted to quantitatively evaluate the over-pressure with a composite origin.Taking the well W2 as a case study,the error between ED+SVR-calculated pressures and measured values was0.1%～1.7%,outperforming the Eaton method,which was 0.0%～6.2%.In adjacent wells,the ED+SVR method yielded errors of 1.0%～3.3%,significantly lower than the Eaton method's 2.0%～11.4%.Analysis showed that the Eaton method relied on calibration with measured pressures to determine the Eaton exponent and was sensitive to changes in overpressure origin contributions,making it suitable for single wells or adjacent wells with available measured data and stable origins.In contrast,the ED+SVR method was not limited by these constraints and generally performed well in pressure evaluation for both single and adjacent wells.Its physical significance and reliability were verified by petrophysical and electrical data,demonstrating strong regional applicability.The study clarifies the composite origin mechanism of overpressure in the Pinghu slope belt of the Xihu Sag and establishes the ED+SVR method as an effective tool for quantitative evaluation of overpres-sure with a composite origin in this area,providing a critical basis for subsequent precise pressure evaluation and exploration deployment in this region.关键词
超压/欠压实/流体膨胀/复合成因/定量评价/平湖斜坡带/东海盆地Key words
overpressure/undercompaction/fluid expansion/composite origin/quantitative evaluation/Pinghu slope belt/East China Sea Basin分类
能源科技引用本文复制引用
姜乃天,范昌育,秦德文,王晓培,王震亮..东海盆地西湖凹陷平湖斜坡带复合成因超压判别及定量评价[J].石油实验地质,2026,48(2):375-385,11.基金项目
中海石油(中国)有限公司上海分公司项目(CCL2023SHPS006RS)资助. （中国）
