姬塬、陕北地区长8_1浅水三角洲水下分流河道砂体对比研究  

Comparative Study of Underwater Distributary Channel Sandbodies in the Shallow-water Delta from Chang 8_1 of Jiyuan and Northern Shaanxi Area

作　　者：李树同[1] 姚宜同 刘志伟[3] 汪洋[1,4] 牟炜卫 闫灿灿[1,4] 

机构地区：[1]甘肃省油气资源研究重点实验室/中国科学院油气资源研究重点实验室,甘肃兰州730000 [2]西南石油大学地球科学与技术学院,四川成都610500 [3]长庆油田分公司工程技术管理部,陕西西安710021 [4]中国科学院大学,北京100049

出　　处：《天然气地球科学》2015年第5期813-822,共10页Natural Gas Geoscience

基　　金：国家科技重大专项(编号:2011ZX05025-006-03);中国科学院战略性先导科技专项(编号:XDA03030300);中国科学院"西部之光"项目联合资助

摘　　要：利用测井、岩心、薄片等资料,从储层沉积学的角度对比研究了姬塬地区和陕北地区长81水下分流河道砂体的迥异性。研究表明:2个地区砂岩均为岩屑长石砂岩和长石岩屑砂岩,属于细砂岩和极细砂岩,但陕北地区砂体粒度比姬塬地区更细,分选更好。姬塬地区砂体厚度大、泥质含量低,叠加期次不明显,垂向和纵向上连续性好;而陕北地区砂体单层厚度薄、泥质含量高,具有明显的多旋回性,垂向和纵向上连续性差。姬塬地区长81属于浅水沉积环境,近物源、物源供给相对稳定且充足,湖水扩张动力大于河流入湖动力,形成了"连续退积式"的厚层砂体;而陕北地区长81同样属于浅水沉积环境,湖水水体相对姬塬地区浅,远物源、供给量稳定但不充足,湖水扩张动力和河水动力均较弱,形成了"拉锯式"的薄层砂体。2个地区砂体孔隙以粒间孔和长石溶孔为主,整体上姬塬地区长81水下分流河道砂体储集性能优于陕北地区,但是陕北地区长81水下分流河道砂体同样具备油气储集能力。Using data of logging,drilling core and thin sections,this paper studies the different properties of underwater distributary channel sandbodies in the shallow-water delta from Chang 81 between Jiyuan and northern Shaanxi area from the perspective of reservoir sedimentology.The study shows that the sandstone from the two areas is lithic-feldspathic sandstone and feldspathic-lithic sandstone,regarded as fine sandstone and very fine sandstone,but the particle size of sandstone in northern Shaanxi area is finer and better sorted than that in Jiyuan area.Jiyuan area has large thickness of sandbodies with low content of shale,unobvious superposition stages,and good continuity in vertical and longitudinal direction.However,northern Shaanxi area has thin monolayer sandbodies with high content of shale,significant multiply cyclicity,and poor continuity in vertical and longitudinal direction.Chang 81 member in Jiyuan area belongs to shallowwater deposits and closes to the provenance,the provenances are enough and have stable supply ability,the driving force of the water expansion is greater than that of the river flowing into the lake,thereby creating a continuous retrogradation thick sandbody.However,Chang 81 member in northern Shaanxi area also belongs to shallow-water deposits where the water is relatively shallower than that in Jiyuan area.It is far away from the provenance which led to stable but insufficient supplication,and the water power of lake and river was weak,forming a see-saw type thin sandbody.The dominating reservoir pore type of the two areas is inter-granular pore and feldspar-dissolved pore.Overall,the sand reservoir performance of underwater distributary channel sandbodies from Chang 81 of Jiyuan area is better than that of northern Shaanxi area;however,the underwater distributary channel sandbodies from Chang 81 of northern Shaanxi area also have hydrocarbon accumulation capacity.

关 键 词：浅水三角洲 水下分流河道 沉积环境 成因模式 鄂尔多斯盆地 

分 类 号：TE122.2[石油与天然气工程—油气勘探]