苏丹Melut盆地北部油田储集层孔隙结构特征分析

对苏丹Melut盆地北部油田储集层孔隙结构研究结果表明，该油层储集层以岩屑石英砂岩及长石石英砂岩为主，结构成熟度、成分成熟度中等；成岩作用类型多样，成岩阶a为早成岩B亚期；孔隙类型以原生粒间孔为主，少量溶蚀孔；孔隙结构以粗孔粗喉型为主，中孔中喉型次之；黏土矿物包括高岭石、伊利石、伊／蒙混层等，其中高岭石含量最高，具有潜在速敏性。分析认为，在油田注水开发时，为防止伤害孔隙结构导致降低开发效果，应将注水速率控制在储集层岩石临界速率以内。图3表3参8

Pore structure characteristics analysis of the oilfield in north Melut Basin, Sudan

The pore structure characteristics of reservoir in the north Melut Basin,Sudan,including the effect of lithology,diagenesis,pore types and clay minerals on pore structure,show that the reservoir's lithology is mainly lithic quartz arenite and feldspathic quartz arenite,and has middle textural and compositional maturity.It has various kinds of diagenesis types and the diagenesis stage belongs to subage of type B in an early stage.Original inter-granular pore is the major pore type along with a few secondary pores and other types of pores in the reservoir.Pore structure is mainly large pore with large throat,followed by medium pore with medium throat.The clay minerals include kaolinite,interstratified zones of illite and smectite,and illite,in which the kaolinite content is the highest and has a destructing role to pore structure because of fast water injection.To prevent from damaging pore structure and reduce the oil recovery cost in waterflooding,the flowing velocity of injected fluid should be below the threshold velocity of rocks.