天然气工业2017，Vol.37Issue(5)：1-9,9.DOI:10.3787/j.issn.1000-0976.2017.05.001
柴西狮子沟地区渐新统下干柴沟组上段膏盐岩沉积演化特征
Evolution characteristic of gypsum-salt rocks of the upper member of Oligocene Lower Ganchaigou Fm in the Shizigou area, western Qaidam Basin
摘要
Abstract
Over years of oil and gas exploration in the Qaidam Basin,reservoirs have been discovered in many layers.In the Shizigou area,western Qaidam Basin,the upper member of Oligocene Lower Ganchaigou Fm is an important target for oil and gas exploration,and gypsum-salt rocks are the high-quality caprocks for the preservation of oil and gas reservoirs in this area.For predicting oil and gas exploration direction and target in the western Qaidam Basin and providing guidance for its oil and gas exploration deployment,its depositional characteristics and environment of gypsum-salt rocks in this area were investigated based on the core observation,thin section identification,and analysis of grain size,sensitivity parameter ratios (Sr/Cu,Fe/Mn,(Fe+Al)/(Ca+Mg),V/(V+Ni) and Pr/Ph),pyrite content and inclusions.The following characteristics are identified.First,gypsum-salt rocks are mainly distributed in the depocenter of the lacustrine basin and their thickness decreases towards the margin of the basin.They are laterally transformed into carbonate rocks or terrigenous clastic rocks.They are areally distributed in the shape of irregular ellipse.Second,gypsum-salt rocks are vertically developed mainly in the middle and upper parts of the upper member of Lower Ganchaigou Fm and they are interbedded with carbonate rocks or terrigenous clastic rocks.Their single layer thickness changes greatly,and there are many layers with good continuity.Third,Sand Group Ⅲ to Group Ⅰ in the upper member of Lower Ganchaigou Fm (intersalt) are of reductive water environment of semi-deep to deep lake facies due to their sedimentation in an arid and hot climate.It is concluded that gypsum-salt rocks of the upper member of Lower Ganchaigou Fm are distributed widely with great accumulative thickness in this area;and that they are originated from deep lake water by virtue of evaporation,concentration and crystallization in an arid and hot climate instead of by hydrothermal fluid.关键词
柴达木盆地西部/狮子沟地区/古近纪/下干柴沟组上段/膏盐岩/盖层/沉积环境/沉积特征/蒸发浓缩Key words
Western Qaidam Basin/Shizigou area/Paleogene/Upper member of Lower Ganchaigou Fm/Gypsum-salt rock/Sedimentary environment/Depositional characteristic/Evaporation and concentration引用本文复制引用
易定红,王建功,石亚军,孙秀健,马新民,王鹏,李延丽..柴西狮子沟地区渐新统下干柴沟组上段膏盐岩沉积演化特征[J].天然气工业,2017,37(5):1-9,9.基金项目
国家科技重大专项“柴达木盆地复杂构造区油气成藏、关键勘探技术与新领域目标优选”(编号:2016ZX05003-006)、中国石油天然气股份有限公司重大科技专项“柴达木盆地建设千万吨油气田综合配套技术研究”(编号:2011-ZG-001004). （编号:2016ZX05003-006）
