志丹油田寨科区延长组长2油层储集条件研究

通过对志丹油田寨科区长2储集层沉积特征、岩石学特征、储层物性、孔隙结构研究及影响储层物性因素分析认为，寨科区长2期为三角洲平原亚相沉积，主要发育平原分流河道微相，砂体发育。储层沉积之后，经历了强烈的成岩作用，压实压溶、自生矿物充填、长石石英次生加大等使储层孔隙减少，物性变差。同时，碎屑颗粒表面自生绿泥石薄膜抑制了成岩过程中自生矿物的充填。使得原生粒间孔有较多保存，强烈的溶蚀作用也使储层物性得到改善。因此，相对陕北其他地区延长组储层而言，研究区延长组长2储层物性条件较好，这也是该区油井产量较高，稳产时间长，成为陕北地区少有的“小而肥”油田的重要原因。

Research on Reservoir Conditions of Chang 2 Reservoir in Yanchang Formation of Zhaike Area, Zhidan Oil Field

Through studying the characteristics of sedimentary, petrology, reservoir physical property, and pore structure and analyzing the effect factors on reservoir physical property of Chang 2 reservoir in Yanchang formation of the Zhaike area, Zhidan oil field, the authors hold that the Chang 2 sedimentation of this area is a delta-plain sub-facies, with the plain distributary channel microfacies and the sand bodies being well developed. After reservoir was deposited, it experienced a strong epigenesis, compaction pressure solution, filling authigenic minerals, and the secondary enlargement of and feldspar and quartz, making the reservoir decrease in porosity and become poor in physical property. Meanwhile, authigenic chlorite film of the debris surface prevented filling authigenic mineral during the diagenetic process, enable more primary intergranular pores to be preserved, and strong dissolution also improved reservoir physical property. Therefore, compared with Yanchang formation of the other areas of northern shaanxi, the physical property of Yanchang formation Chang 2 member in the research area is better, that is the key cause of higher single well production, better stable yield. It is these factors that makes it a ＂small-and- rich＂ oil field in north Shannxi.