现代地质
現代地質
현대지질
GEOSCIENCE-JOURNAL OF GRADUATE SCHOOL CHINA UNIVERSITY OF GEOSCIENCES
2013年
4期
941-948
,共8页
董果果%黄文辉%万欢%王华军
董果果%黃文輝%萬歡%王華軍
동과과%황문휘%만환%왕화군
东营凹陷%固体-流体相互作用%成岩作用%储层特征%孔隙演化
東營凹陷%固體-流體相互作用%成巖作用%儲層特徵%孔隙縯化
동영요함%고체-류체상호작용%성암작용%저층특정%공극연화
Dongying Sag%solid-fluid interaction%diagenesis%reservoir characteristic%porosity evolution
东营凹陷北部沙四上亚段是重要的含油层系,其储层的形成过程和分布规律是近年来的研究难点和热点。通过对研究区样品进行偏光显微镜和荧光观察、扫描电镜分析,并结合区域构造演化史和有机质热演化史,研究东营凹陷北部沙四上亚段的固体-流体相互作用机制及其对储层物性的影响。结果表明研究区可划分出7个流体活动期次,其成岩环境的变化依次为碱性、酸性、碱性、酸性、碱性、酸性至酸碱交替。酸性流体与固体的相互作用表现为明显的碳酸盐溶解、长石溶解及石英的次生加大等,主要改善了储层物性;而碱性流体与固体的相互作用主要表现为石英的溶解、长石次生加大、铁方解石和(铁)白云石及硬石膏沉淀等,在很大程度上堵塞了孔隙,降低了储层物性。研究区共发生两次油气充注,为沙二段到东营组沉积时期以及馆陶组沉积末期,两次油气充注分别对应了两个次生孔隙发育带。
東營凹陷北部沙四上亞段是重要的含油層繫,其儲層的形成過程和分佈規律是近年來的研究難點和熱點。通過對研究區樣品進行偏光顯微鏡和熒光觀察、掃描電鏡分析,併結閤區域構造縯化史和有機質熱縯化史,研究東營凹陷北部沙四上亞段的固體-流體相互作用機製及其對儲層物性的影響。結果錶明研究區可劃分齣7箇流體活動期次,其成巖環境的變化依次為堿性、痠性、堿性、痠性、堿性、痠性至痠堿交替。痠性流體與固體的相互作用錶現為明顯的碳痠鹽溶解、長石溶解及石英的次生加大等,主要改善瞭儲層物性;而堿性流體與固體的相互作用主要錶現為石英的溶解、長石次生加大、鐵方解石和(鐵)白雲石及硬石膏沉澱等,在很大程度上堵塞瞭孔隙,降低瞭儲層物性。研究區共髮生兩次油氣充註,為沙二段到東營組沉積時期以及館陶組沉積末期,兩次油氣充註分彆對應瞭兩箇次生孔隙髮育帶。
동영요함북부사사상아단시중요적함유층계,기저층적형성과정화분포규률시근년래적연구난점화열점。통과대연구구양품진행편광현미경화형광관찰、소묘전경분석,병결합구역구조연화사화유궤질열연화사,연구동영요함북부사사상아단적고체-류체상호작용궤제급기대저층물성적영향。결과표명연구구가화분출7개류체활동기차,기성암배경적변화의차위감성、산성、감성、산성、감성、산성지산감교체。산성류체여고체적상호작용표현위명현적탄산염용해、장석용해급석영적차생가대등,주요개선료저층물성;이감성류체여고체적상호작용주요표현위석영적용해、장석차생가대、철방해석화(철)백운석급경석고침정등,재흔대정도상도새료공극,강저료저층물성。연구구공발생량차유기충주,위사이단도동영조침적시기이급관도조침적말기,량차유기충주분별대응료량개차생공극발육대。
In northern Dongying Sag,the reservoir formation and distribution of upper submember of the fourth member in the Shahejie Formation is the study focus in recent years.It is an important oil-bearing sequence. The solid-fluid interaction mechanism and its influence on physical properties of reservoirs could be studied by the observation of polarizing and fluorescence microscope and the analyses of SEM on thin sections in combina-tion with regional tectonic evolution and thermal history of organic matters.Conclusions are drawn as follows. There are seven active fluid episodes in the variation of diagenetic environment,namely,alkaline,acidic,alka-line,acidic,alkaline,acidic and alternating alkaline and acidic setting,respectively.The interaction of acidic fluid and solid presents significant dissolution of carbonate minerals and feldspar,and quartz overgrowth to enhance the reservoirs;while the interaction of alkaline fluid and solid is characterized by quartz dissolution, feldspar overgrowth and the precipitation of ferrocalcite,ankerite and anhydrite,which largely infill pores and destroy the reservoirs.There are two hydrocarbon expulsion episodes,namely,the deposition period from the second member of Shahejie Formation to Dongying Formation,and the latest one of Guantao Formation.These two events are in correspondence with the development of two secondary pore zones.