南堡3号构造中深层中低渗储层微观孔喉特征

Microscopic Pore- Throat Structure Characterization of Medium- Deepand Medium- Low Permeability Reservoirs in Nanpu Structure3

岩心观察、薄片鉴定、全岩矿物等测试分析表明,南堡3号构造中深层中低渗储层岩石类型为长石砂岩和岩屑长石砂岩,在碎屑组分中长石含量较高,存在钾长石、斜长石、微斜长石等多种类型,进一步观察发现储层碎屑组分成分成熟度和结构成熟度偏低,为近物源快速堆积。利用铸体薄片及分析化验资料进一步分析了储层微观孔喉特征,结果表明:南堡3号构造中深层储层孔隙以次生孔隙为主,主要为粒间溶蚀孔隙、粒内溶蚀孔隙,喉道主要为片状或弯片状喉道,共发育6种孔喉结构,并以中孔细喉型和小孔细喉型为主,储层类型为中等—差储层,对该储层喉道加以改造,可有效改善储层物性。

Core observation,thin section analysisand whole rock- mineral test shown that the medium- deep andmedium- low permeability reservoir rock in Nanpu Structure 3 consists of arkose anddebris- feldspar. The detrital component with relatively high content of feldspar also includes feldspar,plagioclase,microcline,etc. Further observation indicated that thecompositional maturity and textural maturity of the reservoir detrital component are relatively low and it rapidly accumulated by near- source. The reservoir microscopic pore- throat structure was further characterized by using casting thin sections and test data. Result demonstrates that the pores of medium- deep reservoirs in Nanpu Structure3 are dominated by secondary pores,which mainly include intergranular dissolved pores and intragranular dissolved pores. Throats are dominated by lamellar throats and curved lamellar throats. Six types of pore- throat structures were mainly developed in the reservoirs and the dominant types are mesopores- finethroat and micropore- finethroat. Reservoirs wereclassified as medium- poor types and the physical properties of reservoirs can be effectively improved in case of stimulating reservoir throats.