CAJ | 학술논문

渤海湾盆地北塘凹陷古近系沙河街组三段白云岩分布广泛，是重要的油气储集层。根据钻井岩心、岩石薄片、扫描电镜、电子探针和地球化学特征等资料，对沙三段白云岩储层特征及其影响因素进行了详细研究。结果表明，沙三段白云岩有层状、结核状、均匀块状和裂缝充填等4种产状，岩石类型包括泥晶白云岩、粉晶白云岩和细晶白云岩，储集空间主要为次生孔隙和裂缝；白云岩储层物性较差，孔洞缝共同发育的层段是油气富集的有利层段，储层的含油性与储层的岩性及物性具有一定的相关性。目前白云岩储层正处于中成岩阶段，在埋藏过程中经历了机械压实、压溶、胶结、溶蚀、重结晶和白云岩化等成岩作用的改造，其中溶蚀作用可分为三期，后两期溶蚀作用极大地改善了储层物性，机械压实和胶结作用对储层物性起破坏作用；地球化学特征揭示了白云岩化作用的两种类型，即准同生期的回流渗透白云岩化和成岩期的埋藏白云岩化。影响白云岩储层物性的主要因素包括沉积环境、白云岩化作用和裂缝发育程度，沉积环境对白云岩储层物性起决定性作用，白云岩化作用对储集空间具有重要的改造作用，裂缝的发育极大改善了储层物性，提高了储层的储集能力。
발해만분지북당요함고근계사하가조삼단백운암분포엄범，시중요적유기저집층。근거찬정암심、암석박편、소묘전경、전자탐침화지구화학특정등자료，대사삼단백운암저층특정급기영향인소진행료상세연구。결과표명，사삼단백운암유층상、결핵상、균균괴상화렬봉충전등4충산상，암석류형포괄니정백운암、분정백운암화세정백운암，저집공간주요위차생공극화렬봉；백운암저층물성교차，공동봉공동발육적층단시유기부집적유리층단，저층적함유성여저층적암성급물성구유일정적상관성。목전백운암저층정처우중성암계단，재매장과정중경력료궤계압실、압용、효결、용식、중결정화백운암화등성암작용적개조，기중용식작용가분위삼기，후량기용식작용겁대지개선료저층물성，궤계압실화효결작용대저층물성기파배작용；지구화학특정게시료백운암화작용적량충류형，즉준동생기적회류삼투백운암화화성암기적매장백운암화。영향백운암저층물성적주요인소포괄침적배경、백운암화작용화렬봉발육정도，침적배경대백운암저층물성기결정성작용，백운암화작용대저집공간구유중요적개조작용，렬봉적발육겁대개선료저층물성，제고료저층적저집능력。
Dolostone is widely distributed in third section of Palaeogene Shahejie Formation from Beitang Sag in Bohaiwan Basin,which can develop good reservoir properties.In this paper,based on a vast amount of data from core drilling,rock thin sections,scanning electron microscope,electron probe and geochemistry characteristics,we study the characteristics and influencing factors of Sha 3 dolostone reservoir of Palaeogene Shahejie Formation in detail.Dolostone has four types of occurrence,including layered, nodular,massive and fracture filled.It is showed that the Sha 3dolostone reservoir rock types are mainly micrite dolostone,crystal powder dolostone and aplite dolostone.Reservoir space of Sha 3 dolostone reservoir mainly consists of dissolved intergranular pore and fractures.Dolostone reservoir is characterized by poor physical property,and the layer section with pores,caves and fractures can be performed as hydrocarbon enrichment zones.The oiliness of Sha 3 dolostone reservoir has a certain correlation with lithology and physical properties.The Sha 3 dolostone reservoir is now in the stage of mesodiagenesis,and the main diagenesis of which mainly including mechanical compaction,pressure solution,cementation, dissolution,recrystallization and dolomitization.Dissolution can be divided into three stages,and the latter two stages of dissolution lead to improve physical properties of dolostone reservoirs,while mechanical compaction and cementation result in the reducing of physical properties.Geochemistry characteristics reveal two types of dolomitization:penecontemporneous seepage reflux dolomitization and deep buried diagenetic dolomitization.Physical property of dolostone reservoir is mainly influenced by sedimentary environment,dolomitization and fracture development.Sedimentary environment plays a decisive role on the quality of dolostone reservoir and dolomitization plays an important role on the modification of reservoir space.Huge amount of fractures improves physical properties and enhances the reservoir capability of dolostone reservoir.