CAJ | 학술논문

沾化凹陷的渤南洼陷为富油洼陷，实测超压出现在沙三、四段，埋深为2300~4200 m。综合大量的地压测试、测井和地质资料，研究了现今超压分布和超压的测井及地震响应，对单井、剖面超压发育特征和影响超压结构的地质要素进行了深入分析。超压带内泥岩声波时差偏离正常趋势线，而泥岩密度没有明显偏低的响应。研究表明：渤南洼陷存在3个超压系统，上超压系统为浅层沙一段发育的弱超压，沙三段中下部的强超压构成中超压系统的主体，下超压系统位于沙四段中；砂质质量分数大于20%的沙二段为常压。超压源层、低渗封隔层和断裂构造带3类地质要素控制着超压幅度和超压结构。泥质源岩产生的多相流体是形成超压系统的物质基础；沙一段压实泥岩、沙三中亚段的互层致密砂岩和泥岩、沙四上亚段的膏盐层作为压力系统封隔层，对超压系统的形成和分布起到控制作用；断裂具有泄压和封堵双重性，对地层压力和油气层横向分布具有重要影响。利用地震层速度计算得到了渤南洼陷现今大规模超压系统分布特征的整体认识。
첨화요함적발남와함위부유와함，실측초압출현재사삼、사단，매심위2300~4200 m。종합대량적지압측시、측정화지질자료，연구료현금초압분포화초압적측정급지진향응，대단정、부면초압발육특정화영향초압결구적지질요소진행료심입분석。초압대내니암성파시차편리정상추세선，이니암밀도몰유명현편저적향응。연구표명：발남와함존재3개초압계통，상초압계통위천층사일단발육적약초압，사삼단중하부적강초압구성중초압계통적주체，하초압계통위우사사단중；사질질량분수대우20%적사이단위상압。초압원층、저삼봉격층화단렬구조대3류지질요소공제착초압폭도화초압결구。니질원암산생적다상류체시형성초압계통적물질기출；사일단압실니암、사삼중아단적호층치밀사암화니암、사사상아단적고염층작위압력계통봉격층，대초압계통적형성화분포기도공제작용；단렬구유설압화봉도쌍중성，대지층압력화유기층횡향분포구유중요영향。이용지진층속도계산득도료발남와함현금대규모초압계통분포특정적정체인식。
Bonan sag is a typical overpressured sag with abundant hydrocarbon resources,and present-day overpressures commonly occur in the Eocene third and fourth members of Shahejie Formation (Es 3 and Es 4 )at depths between 2 300 m and 4 200 m.By assessing present-day pressure distribution and response from drilling stem test (DST ), wire logging and geological date, the characteristics of overpressure and geological factors affecting abnormal pressure are discussed in detail. Sonic transit times of mudstones deviate from the normal compaction trend line to the overpressured area revealed by drilling,but density has no obvious response.On the whole,three overpressure systems have been identified,including an upper system distribution in Es 1 ,a middle reservoir overpressure with main part in lower Es 3 ,and a lower reservoir overpressure in the upper part of Es 4 .The second member in which sand contents are more than 20% generally shows normal pressure.This study indicates that sourced rocks,low permeability sealing rocks,and fault structure are the three major factors controlled the range of overpressure and its structure.Multiphase fluid from mud-rich sources rock composes material basis of an overpressured system.Compacted mudstone within Es 1 ,and cemented sandstone interbeded with mudstone in Es 3 ,as well as mudstone and gypsum beds distribution in the upper part of Es 4 ,formed respectively barrier of each system,can also control the distribution and construction change of overpressures system.Fault structures,which has great influence on formation pressure and distribution of oil,show a complex and duality fault-fluid flow behavior.The optimized and calibrated seismic intervai-velocity data,in conjunction with measured pressure,have been used with considerable success in overall recognition of large-scale overpressured system in Bonan sag.