摘要
中国北方地区众多的含油气盆地类型使得各盆地中的沉积物充填、成岩演化和储层性质有较大的差异,并最终导致了成岩类型的多样性、成岩演化的多向性和成岩机制的复杂性。中、新生界碎屑岩储层的基本特征是①发育冲积扇—河流—(扇)三角洲—滨浅湖沉积体系,主要油气砂体为三角洲平原和前缘中的辫状分流河道、水下分流河道、河口坝以及滨—浅湖中的滩坝砂体,其次为扇三角洲、浊积扇或湖底扇和河流等砂体。②砂岩储层的成分成熟度较低,以岩屑砂岩为主,其次为长石岩屑砂岩、岩屑长石砂岩和长石砂岩。从早到晚砂岩的成分成熟度趋于降低,与盆地构造演化的活动性逐渐增强是一致的。③砂岩以原生粒间孔隙为主,它的发育程度基本决定了储层性质的优劣;北方地区除了鄂尔多斯盆地三叠系延长统等少数地区发育溶蚀孔隙以致成为主要的储集空间外,大多数油气盆地从整体上讲,砂岩中原生孔隙的相对比例在50.0%以上,是砂岩储集空间的主要构成部分。砂岩孔隙类型的变化明显地表现出4个发育特点。④砂岩的成岩压实作用是储集性质的主要控制因素,各地区砂岩的压实减孔量占总减孔量的比例在50.0%?94.0%之间,基本上是胶结减孔量的2.0?10.0倍。因此,在北方含油气盆地中,研究砂岩的压实减孔规律对成岩作用和钻前储层性质的预测是十?
There are many types of oil and gas basins in North China. They are quite different from one another in sedimentary supply, diagenetic evolution and reservoir properties, ?nally leading to diversity of diagenetic types, diversity of diagenetic evolution and complexity of diagenesis. The basic characteristics of Mesozoic and Cenozoic clastic reservoirs are: (1) development of the alluvial fan – channel – (fan) delta – shore sedimentary system. The main oil and gas sandbodies are delta plain and frontal braided channels, underwater branch channels, mouth bar and shore – shallow lake beach bar sandbody.The secondary sandbodies are fan delta, turbidite fan or sublacustrine fan and channels. (2)The composite of sandstone is at low maturity, mainly the lithic sandstone and secondary feldspathic litharenite, lithic arkose and arkose sandstone. The maturity of sandstone became gradually lower from the early stage to the later stage, compatible with the gradually stronger activities of structural development in the basin. (3)The porosity of sandstone is mainly the original intergranular pore. The evolution of such pore basically determines the quality of the reservoir. Generally speaking, the relative proportion of original pore of sandstone in most of the oil and gas basins in North China exceeds 50 percent, except evolution of dissolved pores in some areas in Triassic Yangchang Formation in Ordos Basin. The original pores are the main space of the sandstone reservoir. Variations in sandstone pore type clearly indicate four evolution characteristics. (4) The diagenetic compaction of sandstone is the main controlling factor of the reservoir property. The amount of reduced pores caused by sandstone compaction in various areas accounts for 50~94 percent of the total amount of reduced pores, basically 2~10 times as high as the amount of reduced cement pores. Therefore, so far as the oil and gas basins in North China are concerned, the study of the law for pore reduction caused by sandstone compaction is of great importance to understanding diagenesis and predicting the reservoir properties before drilling exploration wells. There are many factors controlling sandstone diagenetic compaction. There are four types of the diagenetic mechanism. Based on elaboration on the basic characteristics of Mesozoic and Cenozoic clastic reservoirs in the oil and gas basins in North China, this article also elaborates on evaluation of sandstone reservoir properties and application of prediction for oil and gas exploration.
出处
《中国石油勘探》
CAS
2004年第5期31-39,共9页
China Petroleum Exploration
关键词
储层
勘探实践
碎屑岩
中新生界
含油气盆地
中国北方
reservoirs, exploration practice, clastic rock, Meso-Cenozoic, oil and gas basins, North China.
