Geochemical Characteristics of Crude Oils from Zao-V Oil Measures in Shenjiapu Oilfield

The geochemical characteristics of crude oils from Zao\|Ⅴ oil measures in the Shenjiapu oilfield are systematically described in terms of the fractional composition of crude oils, GC characteristics of saturated hydrocarbon fraction of crude oils and the characteristics of their biomarkers. The depositional environment, type and evolution of the biological source are also discussed. All pieces of evidence such as low saturated hydrocarbon fraction, high resin and asphalt, high isoprenoid alkane, weak odd\|carbon number predominance (CPI ranging from \{1.23\} to \{1.29\}, OEP ranging from \{1.14\} to \{1.16\}) and low sterane and terpane maturity parameters show these crude oils are immature oils. Low Pr/Ph ratios (\{0.66\}-\{0.88\}) and high gammacerance/C\-\{31\} hopane ratios (\{0.59\}-\{0.86\}) indicate the source rocks were formed in a slightly saline to brackish reducing lake depositional environment. Gas chromatographic characteristics of the saturated hydrocarbon fraction and the predominance of C\-\{30\} hopane in terpane series and C\-\{29\} sterane in sterane series indicate the biological source of the crude oils is composed mainly of bacterial and algal organic matter, and some algae are perhaps the main contributor of organic matter to the source rocks.

沈家铺油田枣Ⅴ油组沉积微相类型及其含油性评价

利用岩芯、测井及各种分析化验等资料,通过对各种沉积相识别标志的分析,研究了沈家铺油田枣Ⅴ油组沉积相、沉积微相类型及其特征,认为本区枣Ⅴ油组为扇三角洲前缘亚相沉积,主要微相类型有水下分流河道沉积、水下分流次河道沉积和水下分流河道间沉积。在此基础上,利用岩石热解(Rock-eval)和薄层色谱(TLC-FID)等地球化学分析技术,定量评价了各微相的含油性,这种尝试具有一定的理论意义。

沈家铺油田枣Ⅴ油组原油地球化学特征

对沈家铺油田枣V油组原油有机地球化学特征进行了详细描述,并对母源沉积环境、生源及生油岩演化程度进行了分析。研究结果表明,原油中饱和烃的含量低,非烃沥青质含量高,类异戊二烯烷烃含量高,奇碳数优势弱,成熟度参数低,这些都表明原油具有低成熟度的特点。Pr与Ph含量的比值低(0.66～0.88),伽马蜡烷与C31藿烷含量的比值高(0.59～0.86),这反映出其源岩形成于微咸水—半咸水湖相还原环境。其生油源主要由菌藻类有机质组成,但藻类可能是其源岩有机质的主要贡献者。

小波分析在王官屯油田王26井枣Ⅴ油层组沉积微相研究中的应用

由测井相解释与岩芯观察,结合前人分析资料得知,王26井枣Ⅴ油层组主要沉积冲积扇相扇中亚相。测井相解释的多解性与岩芯资料的不完整局限了精细分析沉积微相特征。借助小波理论、结合测井曲线、岩芯观察,共同分析王26井枣Ⅴ油层组的沉积微相特征。提取了自然电位、自然伽马、电阻率3种测井曲线,经过Daubechies小波分解后重构的第三层细节信号d3,以高分辨率层序地层学为理论指导,着重对该层段的沉积旋回特征进行分析,借此解释其沉积微相及组合特征。研究结果表明,小波分析、测井相、岩芯资料的结合不仅能识别沉积微相类别——辫状河道及河道内部心滩与河道间沼泽,而且能在纵向上精确地反映其沉积微相组合特征——辫状河道的正旋回特征、河道心滩的反旋回特征、辫状河道连续叠加特征。