CAJ | 학술논문

长8油层组是鄂尔多斯盆地姬塬地区最为有利的油气聚集层位之一,本文分析了姬塬地区长8油藏的甾萜烷生物标志化合物特征,探讨了原油成因,并进行油源对比。研究结果表明,原油δ13CPDB值介于-31.11%～-31.57%,与盆地中生界各产层湖相油型油一致。藿烷以C30藿烷占优势,位于北东运聚带上的原油含较高的C29藿烷,18a（H）-30-降新藿烷（C29Ts）次之,重排藿烷和伽马蜡烷含量较低;位于南西运聚区带上的原油C30重排藿烷相对丰度较高,C30重排藿烷与C29降藿烷的比值高（〉1.0）。甾烷中：规则甾烷含量高,含一定量的孕甾烷、升孕甾烷和重排甾烷,aβ和βa构型甾烷丰富,aaa-20R构型甾烷呈不对称＂V＂型分布。油源对比显示,姬塬地区长8油藏的原油形成于弱还原-弱氧化,淡水,微咸水环境,主要来自于长7油层组烃源岩。
장8유층조시악이다사분지희원지구최위유리적유기취집층위지일,본문분석료희원지구장8유장적치첩완생물표지화합물특정,탐토료원유성인,병진행유원대비。연구결과표명,원유δ13CPDB치개우-31.11%～-31.57%,여분지중생계각산층호상유형유일치。곽완이C30곽완점우세,위우북동운취대상적원유함교고적C29곽완,18a（H）-30-강신곽완（C29Ts）차지,중배곽완화가마사완함량교저;위우남서운취구대상적원유C30중배곽완상대봉도교고,C30중배곽완여C29강곽완적비치고（〉1.0）。치완중：규칙치완함량고,함일정량적잉치완、승잉치완화중배치완,aβ화βa구형치완봉부,aaa-20R구형치완정불대칭＂V＂형분포。유원대비현시,희원지구장8유장적원유형성우약환원-약양화,담수,미함수배경,주요래자우장7유층조경원암。
Chang 8 oil reservoir is one of the most important hydrocarbon accumulation horizons in Jiyuan region of Ordos Basin.However,the research on genesis of the oil is still known little.In this paper,sterane and terpane biomarkers of compounds in oil from the region and source rock from Ordos basin were systematically analyzed.The oil is typical lacustrine-derived oil,with d13CPDB value generally from-31.11 ~-31.57‰.Its terpane distribution was characterized by relatively abundant 17α(H),21β(H) – hopanes.The relative content of C29 hopane of Chang 8 oil in NE migration-accumulation zone was higher,C29Ts takes second.The relative content of C30 rearranged hopane in SW migration-accumulation zone is higher,C30* hopane / C29 norhopanes is greater than 1.The oil contains rich pentacyclic triterpanes,a certain amount of pregnane,homo-pregnane,rearranged sterane and enriches αβ and βα isomers,while ααα-20R sterane isomers display an asymmetric "V"type distribution pattern.The biomarker distributions of the oils show that they were formed under a weak reducing and fresh water environment.The results of oil-source rock correlation showed that the oil was mainly derived from Chang-7 source rock.