摘要
塔里木盆地顺托果勒低隆起区顺9井在志留系柯坪塔格组中-下段储盖组合中发现轻质油藏,与柯坪塔格组上段(柯上段)油气性质存在较大差异。为进一步明确研究区志留系油气成藏特征,利用顺9井区钻井获得的原油和含油砂岩开展柯上段与下段可动烃地化特征、储层沥青和流体包裹体特征的对比研究。柯下段原油样品和含油砂岩抽提物均具有较高的饱和烃含量和较低的沥青质含量,而柯上段不同样品间存在差异。柯上段与柯下段具有相似的正构烷烃和甾、萜烷分布特征以及碳同位素组成。25-降藿烷系列化合物仅在柯上段样品中有检出。两个含油层段均可见储层沥青,但赋存及光性特征存在差异。两个含油层段储层流体包裹体特征相似,油包裹体宿主矿物、荧光特征及均一温度分布具有一致性。结合构造演化史和钻井实际情况分析认为,研究区柯上段与柯下段主要经历了一致的一期油气成藏过程,保存条件不同造成油藏差异改造破坏,形成了两个含油层段现今油气性质的差异。柯下段保存条件优于上段,顺9井柯下段轻质油藏可能是加里东晚期-海西早期形成的古老原生油气藏。寻找保存条件好的原生油藏仍然是研究区志留系勘探的重点方向。
A light oil reservoir was discovered in a reservoir-cap assemblage at the middle-to-lower members of the Silurian Kepingtage Formation in Well SH 9 drilled in the low uplifting area of Shuntuoguole region in Tarim Basin.Its properties were found to be quite different from those of the heavy oil reservoirs in the upper members of the Kepingtage Formation.A comparative study of the reservoirs in the upper and lower members was then conducted to better understand their accumulation process through geochemical analyses as well as characterization of reservoir bitumen and fluid inclusions in crude oil and oil-bearing sandstone extracts gathered during the drilling of Well SH 9.The results show that the samples from the lower member all have higher content of saturated hydrocarbon and lower content of asphaltene,but those from the upper member vary greatly from one to another.The two members share the similar distribution of normal alkanes,steranes and terpenes as well as carbon isotopic compositions.However,the 25-norhopanoids compounds are identified only in samples from the upper member.Both members contain reservoir bitumen but with different occurrence and optical properties.Oil inclusions in both members are similar in host mineral,fluorescence characteristics,and homogeneous temperature distributions.Combined with tectonic evolution and drilling activities,the study suggests that both members have experienced the same first stage of hydrocarbon accumulation and formed two petroliferous intervals with different hydrocarbon properties due to different preserving conditions.The lower member has better preservation conditions than the upper member.The light oil reservoir discovered in the lower member is very likely to be an old primary reservoir formed during the Late Caledonian to Early Hercynian,hence the primary oil reservoirs in the Silurian are still the focus of exploration in Shuntuoguole region.
作者
李慧莉
李婧婧
杨素举
马中远
Li Huili;Li Jingjing;Yang Sujyu;Ma Zhongyuan(Petroleum Exploration and Production Research Institute,SINOPEC,Beijing 100083,China;Petroleum Exploration&Production Research Institute,SINOPEC Northwest OilfieldCompany,Urumqi,Xinjiang 830011,China)
出处
《石油与天然气地质》
EI
CAS
CSCD
北大核心
2020年第5期941-952,共12页
Oil & Gas Geology
基金
国家科技重大专项(201705005-002)
中国科学院A类战略性先导科技专项(XDA14010406)。
