第37卷第5期 2016年10月
文章编号：1001-3873(2016)05-0499-08
新疆石油地质
XINJIANG PETROLEUM GEOLOGY DOI: 10.7657/XJPG20160501
Vol.37,No.5 Oct.2016
玛湖凹陷风城组碱湖烃源岩生烃机理及资源量新认识
支东明"，曹剑”，向宝力"，秦志军"，王婷婷？
（1.中国石油新疆油田分公司a.勘探开发研究院；b.实验检测研究院，新疆克拉玛依834000；
2.南京大学地球科学与工程学院，南京210023)
摘要：碱湖烃源岩的生烃特征和机理是学科研究的前缘与难点。以准噶尔盘地玛湖凹陷下二叠统风城组为例，采用烃源岩人工制面、自然剖面、油气特征标定相结合的方法，对这套碱湖烃源岩的生烃特征和机理进行了研究，并据此重新计算了资源量。结果表明，风城组碱潮烃源岩的生烃特征突出表现为转化率高、连续生烃、多期高峰、生油窗长、油质轻、油多气少，不同于传统的潮相优质烃源岩。这种独特的生烃机理在于烃源岩的有机和无机组成2方面。风组碱湖烃源岩的生烃母质以菌、藻类为主，特别是菌类发育，因此生烃具有油多气少、转化率高、连续生烃、油质轻的特色；风城组的矿物组成独特性在于兼具发育碱类矿物和火山矿物，二者对生烃分别起延滞和催化作用，使得烃源岩可以早期生烃、持续生烃、多期高峰、生油窗长。基于这种特殊的生烃特征和机理，重新评估了研究区的资源量，生油量较前期认识提高了25%，生气量减少了13%，这更贴近于目前的勘探实际，对确定下步勘探开发方向具有重要意义。
关键词：准噶尔盆地；玛湖凹陷；风城组；碱潮；烃源岩；生烃特征；生烃机理；资源量中图分类号：TE112.115
文献标识码：A
Fengcheng Alkaline Lacustrine Source Rocks of Lower Permian in Mahu Sag in Junggar Basin:
HydrocarbonGenerationMechanism andPetroleumResourcesReestimation
ZHI Dongming", CAO Jian', XIANG Baoli, QIN Zhijun', WANG Tingting
(1.PetroChina Xinjiang Oilfield Company, a.Research Institute of Exploration and Development, b.Research Institute of Experiment and
Detection, Karamay, Xinjiang 834000, China; 2.School of Earth Sciences and Engineering, Nanjing University
Nanjing, Jiangsu 210023, China)
Abstract: Hydrocarbon generation characteristics and mechanism of alkaline-lacustrine source rocks are one of the research leading edges and difficulties. Based on a case study in the Lower Permian Fengcheng formation in the Mahu sag of Junggar basin, by using comprehan-sive methods of artificial section and natural outcrop of the source rocks as well as oil and gas characteristic calibration, the paper studies hydrocarbon generation characteristics and mechanism of the alkaline-lacustrine source rocks, based on which petroleum resources are re-estimated. Results show that the Fengcheng alkaline-lacustrine source rocks exhibit some unique characteristics in hydrocarbon generation such as high conversion efficiency, continued hydrocarbon generation, multi-phase generation peaks, long oil-generation window, light oil and high oil to gas ratio, all of which are different from conventional lacustrine high quality source rocks., The unique hydrocarbon genera-tion mechanism should be attributed to organic and inorganic compositions of the source rocks, The bioprecursors in the source rocks are dominated by bacteria and algae, with bacteria much more developed., The unique mineral composition of the Fengcheng formation is char-acterized by the existence of both alkaline and volcanic minerals that play retarding and catalytic roles on hydrocarbon generation, respec-tively, which allows early and eontinued hydrocarbon generation, multi-phase generation peaks and long oil-generation window of source rocks. According to these, the reestimation of petroleum resources in the study area is as follows: the oil generating volume is increased by 25% and the gas generating volume is decreased by 13%, which are more accordant with the present-day exploration results and have sig-nificance for making future exploration strategies.
Keywords: Junggar basin; Mahu sag; Fengcheng formation; alkaline lake; source rock; hydrocarbon generation characteristic; hydrocarbon
generation mechanism; petroleum resource
准噶尔盆地是中国西北地区的一个大型叠合型含油气盆地"-"，玛湖凹陷下二叠统风城组的湖相烃源岩，是盆地西北缘克拉玛依一乌尔禾和玛湖两大百里油区形成的物质基础4-7。因此，风城组烃源岩是长期以来的研究热点。但随油气勘探程度的加深，对资源量
收稿日期：2016-05-23
修订日期：2016-06-30
基金项目：国家油气重大专项（2016ZX05001-005）
和产油气性质等需要重新认识，一是当前已经出现了储量接近甚至高于剩余资源量的现象；二是依传统生烃模式，风城组应油气共生，油质偏重，但实际上勘探发现的是油多气少、原油轻质，且在沉积中心烃源岩进人高演化阶段(镜质体反射率近1.6%)后仍以生油为主。
作者简介：支东明（1971-），男，上海人，高级工程师，石油地质，（Tel)09906882729(Email)zhidm@petrochina.com.cn 万方数据