吉林大学学报（地球科学版）
吉林大學學報（地毬科學版）
길림대학학보（지구과학판）
JOURNAL OF JILIN UNIVERSITY(EARTH SCIENCE EDITION)
2014年
6期
1747-1759
,共13页
王淑萍%徐守余%董春梅%王丽萍%刘春平
王淑萍%徐守餘%董春梅%王麗萍%劉春平
왕숙평%서수여%동춘매%왕려평%류춘평
成岩作用%天然气储层%沙四下亚段%砂砾岩体%东营凹陷%致密砂岩
成巖作用%天然氣儲層%沙四下亞段%砂礫巖體%東營凹陷%緻密砂巖
성암작용%천연기저층%사사하아단%사력암체%동영요함%치밀사암
diagenesis%natural gas reservoirs%the lower part of the Fourth Member of the Shahejie Formation of the Paleogene%glutenite bodies%Dongying depression%tight sandstone
由于对东营凹陷民丰洼陷北带深层天然气储层成岩作用特征及其对储层的控制作用认识不清，给该地区天然气勘探带来了极大的风险。综合运用铸体薄片、扫描电镜观察、流体包裹体分析及岩心物性分析等多种技术方法，对东营凹陷民丰洼陷北带沙四下亚段深层天然气储层成岩作用特征及其对储层物性的影响进行了系统的研究。结果表明，该区北带沙四下亚段深层天然气储层为近岸水下扇砂砾岩，成岩作用具有强压实、欠压实、多期溶解、多期胶结、复杂交代和灰泥组分重结晶的特征。主要胶结溶解作用序列为长石溶解/石英次生加大→碳酸盐胶结/石英溶解→碳酸盐胶结物溶解/石英次生加大→黄铁矿胶结/沥青充填。近岸水下扇不同亚相(微相)沉积特征的差异性导致了埋藏过程中成岩作用的差异性，并决定了储集物性的差异性。扇根砾岩在埋藏过程中成岩作用以压实作用和灰泥杂基重结晶作用为主，溶解作用微弱，物性持续降低。在中深层灰泥杂基的重结晶作用使扇根砾岩物性快速降低而形成致密层，扇根砾岩全部为干层。由于早期异常高压和早期油气充注对储层保护以及酸性溶解对储层改造的综合作用，扇中辫状水道远离泥岩、砂砾岩储层在中深层仍发育大量原生孔隙和少量的次生孔隙，储层物性较好，可作为良好的天然气储层。扇中辫状水道靠近泥岩层储层、扇中水道间以及扇缘部位因发生强烈胶结作用，在砂体顶底形成致密的胶结壳，可作为较好的盖层。
由于對東營凹陷民豐窪陷北帶深層天然氣儲層成巖作用特徵及其對儲層的控製作用認識不清，給該地區天然氣勘探帶來瞭極大的風險。綜閤運用鑄體薄片、掃描電鏡觀察、流體包裹體分析及巖心物性分析等多種技術方法，對東營凹陷民豐窪陷北帶沙四下亞段深層天然氣儲層成巖作用特徵及其對儲層物性的影響進行瞭繫統的研究。結果錶明，該區北帶沙四下亞段深層天然氣儲層為近岸水下扇砂礫巖，成巖作用具有彊壓實、欠壓實、多期溶解、多期膠結、複雜交代和灰泥組分重結晶的特徵。主要膠結溶解作用序列為長石溶解/石英次生加大→碳痠鹽膠結/石英溶解→碳痠鹽膠結物溶解/石英次生加大→黃鐵礦膠結/瀝青充填。近岸水下扇不同亞相(微相)沉積特徵的差異性導緻瞭埋藏過程中成巖作用的差異性，併決定瞭儲集物性的差異性。扇根礫巖在埋藏過程中成巖作用以壓實作用和灰泥雜基重結晶作用為主，溶解作用微弱，物性持續降低。在中深層灰泥雜基的重結晶作用使扇根礫巖物性快速降低而形成緻密層，扇根礫巖全部為榦層。由于早期異常高壓和早期油氣充註對儲層保護以及痠性溶解對儲層改造的綜閤作用，扇中辮狀水道遠離泥巖、砂礫巖儲層在中深層仍髮育大量原生孔隙和少量的次生孔隙，儲層物性較好，可作為良好的天然氣儲層。扇中辮狀水道靠近泥巖層儲層、扇中水道間以及扇緣部位因髮生彊烈膠結作用，在砂體頂底形成緻密的膠結殼，可作為較好的蓋層。
유우대동영요함민봉와함북대심층천연기저층성암작용특정급기대저층적공제작용인식불청，급해지구천연기감탐대래료겁대적풍험。종합운용주체박편、소묘전경관찰、류체포과체분석급암심물성분석등다충기술방법，대동영요함민봉와함북대사사하아단심층천연기저층성암작용특정급기대저층물성적영향진행료계통적연구。결과표명，해구북대사사하아단심층천연기저층위근안수하선사력암，성암작용구유강압실、흠압실、다기용해、다기효결、복잡교대화회니조분중결정적특정。주요효결용해작용서렬위장석용해/석영차생가대→탄산염효결/석영용해→탄산염효결물용해/석영차생가대→황철광효결/력청충전。근안수하선불동아상(미상)침적특정적차이성도치료매장과정중성암작용적차이성，병결정료저집물성적차이성。선근력암재매장과정중성암작용이압실작용화회니잡기중결정작용위주，용해작용미약，물성지속강저。재중심층회니잡기적중결정작용사선근력암물성쾌속강저이형성치밀층，선근력암전부위간층。유우조기이상고압화조기유기충주대저층보호이급산성용해대저층개조적종합작용，선중변상수도원리니암、사력암저층재중심층잉발육대량원생공극화소량적차생공극，저층물성교호，가작위량호적천연기저층。선중변상수도고근니암층저층、선중수도간이급선연부위인발생강렬효결작용，재사체정저형성치밀적효결각，가작위교호적개층。
The diagenetic characteristics of deep natural gas reservoirs and the control of diagenesis on reservoirs in the lower part of the Fourth Member of the Shahejie Formation (Es 4 x)in the north zone of the Minfeng sag in the Dongying depression haven’t been clearly understood,which have led to great risks to hydrocarbon exploration in this area.Based on a combination of thin-section identification, scanning electron microscope (SEM) observation,fluid inclusion analysis and an analysis of core properties,it has been systematically studied about the diagenetic characteristics and its influence on the reservoir property. Nearshore subaqueous fan glutenite is the main regional reservoirs, and the diagenesis is characterized by strong compaction,poor compaction,dissolution and cementation of many stages,complex metasomatism and lime-mud matrix recrystallization.The main cementation-dissolution sequence is feldspar dissolution/quartz overgrowth → carbonate cementation / quartz dissolution →carbonate dissolution /quartz overgrowth → pyrite cementation and bitumen filling.The difference of sedimentary characteristics in different sub/micro-facies of nearshore subaqueous fan controls the difference of diagenetic characteristics, which also determines the difference of reservoir physical property. The conglomerate in inner fan mainly experiences compaction and lime-mud matrix recrystallization,with weak dissolution,and its physical properties keep reducing.The lime-mud matrix recrystallization results in a rapid reduction of physical properties in middle-deep layers.The present physical property of inner fan becomes extremely poor and mainly develops dry layers.Because acid dissolution reconstruct the reservoirs and early hydrocarbon filling and abnormal high pressure can protect reservoirs,the reservoirs far away from mudstone layers in the braided channels of middle fan develop a great number of primary pores and a few secondary pores,have a higher porosity and permeability,and can be effective reservoirs for natural gas.The parts in interdistributaries of middle fan and outer fan develop intensively cementation,it forms dense cemented crusts at the top of the sandstone,and therefore they mainly act as cap rocks.
