南海北部深水区白云凹陷古近系烃源岩的早期预测
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摘要
烃源岩评价是深水区油气勘探非常关键的问题,由于深水区没有井钻穿始新统,所以本研究只能根据相邻浅水区钻井和区域对比的方法,通过层序地层格架、沉积相、地震相、地震速度岩性等资料与相邻地区对比识别烃源岩,确定烃源岩的性质和分布。白云凹陷古近系地层沉积中,沉积密集段具有如下特征:(1)准层序逐步向岸推进;(2)陆源碎屑物质供应不足;(3)水体相对较深的中深湖细粒沉积发育。地震反射特征与有利烃源岩具有良好的对应关系,白云凹陷恩平组湖扩体系域和文昌组湖扩体系域发育中弱振幅、中低频率和中高连续性地震相,是有利烃源岩发育区。利用单井资料建立起一个通过孔隙度来预测烃源层有机质成熟度的预测模型,泥岩孔隙度可以较容易从地震信息中获取,从而对白云凹陷的烃源层的热演化程度进行初步评价。根据沉积相与有机相的关系,直接将沉积相转换为有机相,预测有机相类型。在白云凹陷深水烃源岩预测实践的基础上,本文总结了一套深水区烃源岩早期评价方法,包括:(1)层序格架分析法确定有利烃源岩发育的垂向位置;(2)地震反射特征分析法确定烃源岩的横向分布范围;(3)根据泥岩层速度计算烃源岩热成熟度;(4)沉积相转有机相预测有机相类型。(5)对烃源岩进行综合评价优选次洼。
Source rock is very important for deepwater. Because there is no well piercing the Eocene strata, regional correlation method is applied to identify the source rock and define its distribution in Baiyun Depression, including the correlation of subsidence rate, sedimentary facies, seismic facies and seismic velocity lithology with the adjacent areas. The condensed section in the Paleogene strata of Baiyun Depression has three features: ① parasequences moved forward the shore; ② the supply of terrigenous detrital material was not enough; ③ semideep lacustrine fine sediment developed well. The seismic reflection characters are well corresponding to the favored source rock. The seismic facies of medium-weak amplitude, medium-low frequency and medium-high continuity of lake progressive system tracts of Enping and Wenchang Formation in Baiyun Depression is the area of favored source rock. A forecast model is built up for the degree of organic maturity of source beds with single well and the mudstone porosity which can be got easily from the seismic information. This model is then applied to evaluate the thermal evolution degree of the source beds in Baiyun depression preliminarily. Based on the research of Baiyun depression, this paper represents a Methodology of evaluation on source rocks of deep water. This methodology includes five aspects: (1) analysis of sequence stratigraphy to determine the main formation of source rocks, (2) analysis of seismic reflectance signature to determine the occurring position of source rocks, (3) prediction of vitrinite reflectance based on mudstone velocity to determine the maturation of source rocks, (4) prediction of types of organic facies based on the conversion from sedimentary facies to organic facies, (5) comprehensive evaluation to select optimum hydrocarbon-generating sag.
Source rock is very important for deepwater. Because there is no well piercing the Eocene strata, regional correlation method is applied to identify the source rock and define its distribution in Baiyun Depression, including the correlation of subsidence rate, sedimentary facies, seismic facies and seismic velocity lithology with the adjacent areas. The condensed section in the Paleogene strata of Baiyun Depression has three features: ① parasequences moved forward the shore; ② the supply of terrigenous detrital material was not enough; ③ semideep lacustrine fine sediment developed well. The seismic reflection characters are well corresponding to the favored source rock. The seismic facies of medium-weak amplitude, medium-low frequency and medium-high continuity of lake progressive system tracts of Enping and Wenchang Formation in Baiyun Depression is the area of favored source rock. A forecast model is built up for the degree of organic maturity of source beds with single well and the mudstone porosity which can be got easily from the seismic information. This model is then applied to evaluate the thermal evolution degree of the source beds in Baiyun depression preliminarily. Based on the research of Baiyun depression, this paper represents a Methodology of evaluation on source rocks of deep water. This methodology includes five aspects: (1) analysis of sequence stratigraphy to determine the main formation of source rocks, (2) analysis of seismic reflectance signature to determine the occurring position of source rocks, (3) prediction of vitrinite reflectance based on mudstone velocity to determine the maturation of source rocks, (4) prediction of types of organic facies based on the conversion from sedimentary facies to organic facies, (5) comprehensive evaluation to select optimum hydrocarbon-generating sag.
引文
①王春修,等.珠江口盆地凹陷发育及湖相烃源岩的沉积.1994
1 赵政璋,何海清.中国石油近几年新区油气勘探成果及下步工作面临的挑战和措施.沉积学报.2004(22),增刊:1~7[Zhao Zheng-zhang,He Haiqing.Recent oil and gas exploration harvests in the new area of Petrochina and future challenges and measures.Acta Sedimen-tologica Sinica,2004,22(suppl.):1~7]
2 陈建文.深水盆地油气勘探新领域.海洋地质动态.2003,19(8):38~41[Chen Jianwen.Newexploration domain for oil and gas in deep water basins.Marine Geology Letters,2003,19(8):38~4]
3 金春爽,乔德武,姜春燕.国内外深水区油气勘探新进展.海洋地质动态.2003,19(10):20~23[Jin Chunshuang,Qiao Dewu,Jiang Chunyan.Advances of oil and gas explorations in worldwide deepwater.Marine Geology Letters,2003,19(10):20~23]
4 孙清,连琏.中国深水海域油气及相关资源勘探开发进展及关键技术.中国海洋大学学报(自然科学版)2005,35(6):1049~1052.[Sun Qing,Lian Lian.Key technologies with development of explora-tion and exploitation of the deep-water oil and gas and gas hydrates in South China Sea.Journal of Ocean University of China,2005,35(6):1049~1052]
5 张厚福,张万选,等.石油地质学.北京:石油工业出版社,2000[Zhang Houfu,Zhang Wanxuan,et al.Petroleum Geology.Beijing:Petroleum Industry Press,2000]
6 Schmoker J W.Sand porosity as a function of thermal maturity.Geolo-gy,1988,16(11):1007~1010
7 朱筱敏.层序地层学.山东东营:石油大学出版社,2000[Zhu Xi-aomin.Sequence Stratigraphy.Dongyin Shandong:Press of University of Petroleum,2000]
8 刘震,吴因业.层序地层框架与油气勘探.北京:石油工业出版社,1999[Liu Zhen,Wu Yingye.Sequence Stratigraphy Frame and Explo-ration Activity.Beijing:Petroleum Industry Press,1999]
9 刘震.储层地震地层学.北京:地质出版社,1997[Liu Zhen.Reser-voir Seismic Stratigraphy.Beijing:Geological Publishing House,1997]
10 卢书锷.有关烃类运移的模拟研究.全国油气运移学术讨论会,1987.11[Lu Shu′e.Simulation study of hydrocarbon migration.Na-tionwide Oil Migration Workshop,1987.11]
11 刘震,孙强,武耀辉.洪浩尔舒特凹陷下白垩统热成熟度地震预测.石油实验地质,1997,19(4):372~376[Liu Zhen,Sun Qiang,Wu Yaohui.Thermal maturity seismic prediction of lower Crataceous in Hunhorshout depression.Petroleum Geology&Experiment,1997,19(4):372~376]
12 朱光有,金强.烃源岩的非均质性研究———以东营凹陷牛38井为例.石油学报,2002,23(5):34~39[Zhu Guangyou,Jin Qiang.Study on source rock heterogeneity:a case of Niu-38well in Dongying Depression.Acta Petrolei Sinica,2002,23(5):34~39]
1 赵政璋,何海清.中国石油近几年新区油气勘探成果及下步工作面临的挑战和措施.沉积学报.2004(22),增刊:1~7[Zhao Zheng-zhang,He Haiqing.Recent oil and gas exploration harvests in the new area of Petrochina and future challenges and measures.Acta Sedimen-tologica Sinica,2004,22(suppl.):1~7]
2 陈建文.深水盆地油气勘探新领域.海洋地质动态.2003,19(8):38~41[Chen Jianwen.Newexploration domain for oil and gas in deep water basins.Marine Geology Letters,2003,19(8):38~4]
3 金春爽,乔德武,姜春燕.国内外深水区油气勘探新进展.海洋地质动态.2003,19(10):20~23[Jin Chunshuang,Qiao Dewu,Jiang Chunyan.Advances of oil and gas explorations in worldwide deepwater.Marine Geology Letters,2003,19(10):20~23]
4 孙清,连琏.中国深水海域油气及相关资源勘探开发进展及关键技术.中国海洋大学学报(自然科学版)2005,35(6):1049~1052.[Sun Qing,Lian Lian.Key technologies with development of explora-tion and exploitation of the deep-water oil and gas and gas hydrates in South China Sea.Journal of Ocean University of China,2005,35(6):1049~1052]
5 张厚福,张万选,等.石油地质学.北京:石油工业出版社,2000[Zhang Houfu,Zhang Wanxuan,et al.Petroleum Geology.Beijing:Petroleum Industry Press,2000]
6 Schmoker J W.Sand porosity as a function of thermal maturity.Geolo-gy,1988,16(11):1007~1010
7 朱筱敏.层序地层学.山东东营:石油大学出版社,2000[Zhu Xi-aomin.Sequence Stratigraphy.Dongyin Shandong:Press of University of Petroleum,2000]
8 刘震,吴因业.层序地层框架与油气勘探.北京:石油工业出版社,1999[Liu Zhen,Wu Yingye.Sequence Stratigraphy Frame and Explo-ration Activity.Beijing:Petroleum Industry Press,1999]
9 刘震.储层地震地层学.北京:地质出版社,1997[Liu Zhen.Reser-voir Seismic Stratigraphy.Beijing:Geological Publishing House,1997]
10 卢书锷.有关烃类运移的模拟研究.全国油气运移学术讨论会,1987.11[Lu Shu′e.Simulation study of hydrocarbon migration.Na-tionwide Oil Migration Workshop,1987.11]
11 刘震,孙强,武耀辉.洪浩尔舒特凹陷下白垩统热成熟度地震预测.石油实验地质,1997,19(4):372~376[Liu Zhen,Sun Qiang,Wu Yaohui.Thermal maturity seismic prediction of lower Crataceous in Hunhorshout depression.Petroleum Geology&Experiment,1997,19(4):372~376]
12 朱光有,金强.烃源岩的非均质性研究———以东营凹陷牛38井为例.石油学报,2002,23(5):34~39[Zhu Guangyou,Jin Qiang.Study on source rock heterogeneity:a case of Niu-38well in Dongying Depression.Acta Petrolei Sinica,2002,23(5):34~39]
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