陕西安塞油田长2和长3储层特征及其非均质性
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摘要
安塞油田长2、长3油层组主要发育辫状河和曲流河沉积,其中河道砂体展布形态受沉积微相控制,呈NE—SW向带状展布,是主要的油气储集层。原生粒间孔和次生粒间溶蚀孔是目的层位的主要孔隙类型,孔喉结构为中小孔—中细喉型及小孔—微喉型,前者为中上等储层,后者为中等储层。储集层孔隙结构和渗透性受成岩事件的影响较大,主要包括机械压实-化学压溶作用、胶结作用和溶蚀作用等。储层孔隙丧失的主要原因是压实、压溶作用和胶结作用,其中,石英、长石次生加大和方解石胶结是造成储层物性降低的主要原因,而包围在碎屑颗粒周围的绿泥石薄膜一方面使粒间孔减小,另一方面阻止了部分石英、长石加大及方解石的沉淀,在一定程度上保存了部分原生粒间孔隙,从而使储层物性较好。表生成岩阶段的大气降水及晚成岩阶段有机质分解形成的酸性流体,是碎屑长石和部分胶结物溶解从而形成大量次生孔隙的主要介质。安塞油田长2和长3油层组在纵向上隔夹层较发育,沉积韵律主要为正反复合韵律,导致了储层较强的非均质性,其中长3油层组较长2油层组非均质性强。
There are braid river and meandering river sediments of Chang 2 and Chang 3 oil reservoirs in the Ansai oilfield. The channel sandstone bodies are in NE-SW striking zoning distribution, controlled by sedimentary microfacies, and the sand bodies of river channel are the main reservoirs for the hydrocarbon. Syngenetic open space and vugular-solution pores are main pore types of Chang 2 and Chang 3 oil reservoir sandstones in the Ansai oilfield. Chang 2 and Chang 3 sandstone belongs to the medium or fairly good reservoir whose pore-throat structure belongs mainly to medium-thin throat-eyelet type and thin-small throat- eyelet type. The reservoir quality of the Upper Triassic Chang 2 and Chang 3 sandstones of the Ansai oilfield in Ordos Basin was strongly influenced by the diagenetic events which mainly included mechanical-chemical impaction, consolidation and dissolution.The mechanicalchemical impaction and consolidation were the main factors causing the loss of pores in the sandstones.In the cements,quartz-feldspar overgrowths and carbonate were the main cements that reduced the reservoir quality of the sandstones.Thin chlorite film around detrital grains partially prevented quartz and feldspar overgrowth and carbonate cement precipitation,which caused the preservation of a part of primary pores and hence resulted in a better reservoir quality and the decrease of intergranular space. The main factors for the formation of great quantities of secondary pores were the dissolution of detrital feldspars and part of cements by the meteoric water during epidiagenesis and the acidic liquid related to decomposition of organic mater during hydrocarbon enrichment at the late diagenetic stage. There are many barriers and interbeds in Chang 2 and Chang 3 oil reservoirs, and the sedimentary rhythms are composed of positive rhythms and reverse rhythms which result in the heterogeneity of the competent reservoir, in which the heterogeneity of Chang 3 oil reservoir is stronger than that of Chang 2 oil reservoir in the Ansai oilfield.
There are braid river and meandering river sediments of Chang 2 and Chang 3 oil reservoirs in the Ansai oilfield. The channel sandstone bodies are in NE-SW striking zoning distribution, controlled by sedimentary microfacies, and the sand bodies of river channel are the main reservoirs for the hydrocarbon. Syngenetic open space and vugular-solution pores are main pore types of Chang 2 and Chang 3 oil reservoir sandstones in the Ansai oilfield. Chang 2 and Chang 3 sandstone belongs to the medium or fairly good reservoir whose pore-throat structure belongs mainly to medium-thin throat-eyelet type and thin-small throat- eyelet type. The reservoir quality of the Upper Triassic Chang 2 and Chang 3 sandstones of the Ansai oilfield in Ordos Basin was strongly influenced by the diagenetic events which mainly included mechanical-chemical impaction, consolidation and dissolution.The mechanicalchemical impaction and consolidation were the main factors causing the loss of pores in the sandstones.In the cements,quartz-feldspar overgrowths and carbonate were the main cements that reduced the reservoir quality of the sandstones.Thin chlorite film around detrital grains partially prevented quartz and feldspar overgrowth and carbonate cement precipitation,which caused the preservation of a part of primary pores and hence resulted in a better reservoir quality and the decrease of intergranular space. The main factors for the formation of great quantities of secondary pores were the dissolution of detrital feldspars and part of cements by the meteoric water during epidiagenesis and the acidic liquid related to decomposition of organic mater during hydrocarbon enrichment at the late diagenetic stage. There are many barriers and interbeds in Chang 2 and Chang 3 oil reservoirs, and the sedimentary rhythms are composed of positive rhythms and reverse rhythms which result in the heterogeneity of the competent reservoir, in which the heterogeneity of Chang 3 oil reservoir is stronger than that of Chang 2 oil reservoir in the Ansai oilfield.
引文
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[17]王琪,史基安,薛莲花,等.碎屑储集岩成岩演化过程中流体-岩石相互作用特怔——以塔里木盆地西南坳陷地区为例[J].沉积学报,1999,17(4):584-590.
[18]袁静,赵澄林.水介质的化学性质和流动方式对深部碎屑岩储层成岩作用的影响[J].石油大学学报,2000,24(1):60-63.
[19]罗静兰,Morad S,阎世可,等.河流-湖泊三角洲相砂岩成岩作用的重建及其对储层物性演化的影响——以延长油区侏罗系—上三叠统砂岩为例[J].中国科学(D辑),2001,31(12):1006-1016.
[20]Giles M R,DeBoer R B.Origin and significance of redistributional secondary porosity[J].Marine and Petroleum Geology,1990,6:378-397
[21]裘亦楠.中国陆相碎屑岩储层沉积学的进展[J].沉积学报,1992,10(3):16-24
[2]罗静兰,张晓莉,张云翔,等.成岩作用对河流-三角洲相砂岩储层物性演化的影响——以延长油区上三叠统延长组长2砂岩为例[J].沉积学报,2001,19(4):541-547.
[3]武富礼,李文厚,李玉宏,等.鄂尔多斯盆地上三叠统延长组三角洲沉积及演化[J].古地理学报,2004,6(3):307-315.
[4]邓秀芹,蔺昉晓,刘显阳,等.鄂尔多斯盆地三叠系延长组沉积演化及其与早印支运动关系的探讨[J].古地理学报,2008,10(2):159-166.
[5]胡望水,卫小龙,丛岩,等.测井相在沉积相中的应用——以长岭凹陷大情字井油田黑46区青山口组为例[J].重庆科技学院学报(自然科学版),2013,15(1):1-3.
[6]蔺宏斌,姚泾利.鄂尔多斯盆地南部延长组沉积特性与物源探讨[J].西安石油学院学报(自然科学版),2000,15(5):7-9.
[7]宋凯,吕剑文,杜金良,等.鄂尔多斯盆地中部上三叠统延长组物源方向分析与三角洲沉积体系[J].古地理学报,2002,4(3):59-66.
[8]兰叶芳,黄思静,吕杰.储层砂岩中自生绿泥石对孔隙结构的影响——来自鄂尔多斯盆地上三叠统延长组的研究结果[J].地质通报,2011(30):134-140.
[9]李志伟,刘颖梅.安塞油田长2、长3浅油层特征研究[J].低渗透油气田,2000,5(2):14-18.
[10]罗蛰潭,王允诚.油气储集层的孔隙结构[M].北京:科学出版社,1986:201-205.
[11]庞雯,郭德运,赵靖舟,等.鄂尔多斯盆地甘谷驿油田东区长6储层特征及储层评价[J].兰州大学学报(自然科学版),2004,40(5):96-99.
[12]郭艳琴,王起琮,厐军刚,等.安塞油田长2、长3浅油层成岩作用及孔隙结构特征[J].西北大学学报(自然科学版),2007,37(3):443-448.
[13]Paxton S T,Szabo J O,Calvert C S,et al.Preservation of primary porosity in deeply buried sandstones:A new piay concept from the Cretaceous Tuscaloosa Sandstone of Louisiana[C]//AAPG Annual Convention with DPA/EMD divisions and SEPM.Technical program with abstracts.AAPG Bulletin,1990,74:737
[14]Szabo J O,Paxton S T.Intergranular volume(IGV)decline curves for evaluating and predicting compaction and porosity loss in Sandstones[C]//AAPG 1991 Annual Convention with DPA/EMD divisions and SEPM.Technical program with abstracts.AAPG Bulletin,1991,75:678
[15]Oelkers E H,Bjorkum P A,Murphy W M.A Petrographic and computational investigation of quartz cementation and porosity reduction in North sea sandstones[J].American Journal of science,1996,296:420-452.
[16]Surdam R C,Crossey L J,Hagen E S,Heasler H P.Organic-inorganic interaction and sandstone diagenesis[J].AAPG Bulletin,1989,78(1):l-23.
[17]王琪,史基安,薛莲花,等.碎屑储集岩成岩演化过程中流体-岩石相互作用特怔——以塔里木盆地西南坳陷地区为例[J].沉积学报,1999,17(4):584-590.
[18]袁静,赵澄林.水介质的化学性质和流动方式对深部碎屑岩储层成岩作用的影响[J].石油大学学报,2000,24(1):60-63.
[19]罗静兰,Morad S,阎世可,等.河流-湖泊三角洲相砂岩成岩作用的重建及其对储层物性演化的影响——以延长油区侏罗系—上三叠统砂岩为例[J].中国科学(D辑),2001,31(12):1006-1016.
[20]Giles M R,DeBoer R B.Origin and significance of redistributional secondary porosity[J].Marine and Petroleum Geology,1990,6:378-397
[21]裘亦楠.中国陆相碎屑岩储层沉积学的进展[J].沉积学报,1992,10(3):16-24