伊犁盆地伊宁凹陷二叠系-侏罗系储层评价与预测

Evaluation and Prediction of Permian-Jurassic Reservoir in Yining Depression,Yili Basin

基于露头、钻井、薄片及地震等分析化验资料的综合研究表明,伊宁凹陷二叠系—侏罗系砂岩储层的主要沉积微相类型为冲积扇相和扇三角洲分流河道相、浊积扇相等,粒度整体偏粗,以岩屑和长石溶蚀孔隙为主,二叠系储层属于Ⅲ级储层,三叠系和侏罗系均属于Ⅱ级储层。根据测井约束地震反演得出储层砂岩厚度及孔隙度等值线图反映较厚的有利砂岩储层受凹陷结构和沉积微相控制,在近源的凹陷北部和东部冲积扇和扇三角洲地区加厚;孔隙度与砂体厚度及沉积微相有关,在凹陷北部厚层砂岩分布区和中南部成分及结构成熟度高值区局部增大。有利的较高孔隙度厚层砂岩主要发育在工区北部和东部的河道带上。

The comprehensive study,based on analysis of outcrops,cores,thin sections and seismics,demonstrate that the main sedimentary facies of Permian-Jurassic reservoirs in Yining Depression are alluvial fans,fan delta distributary channels and turbidite fans.The whole reservoir rock was nearly coarse-grained and most of the pores are filled with feldspar grains and fragments secondary dissolution pore,Permian reservoir with pore texture of grade Ⅲ,Triassic and Jurassic reservoirs with pore texture of grade Ⅱ.By the logging constrained seismic inversion thickness and porosity of reservoir sandstones,the authors found that favorable sandstones controlled by depression structure and sedimentary facies.Alluvial fan sandstones and fan delta sandstones were thick in the northern and eastern.The porosity was related to the thickness of sandstones and sedimentary facies.In the northern,where sandbodies were extensively distributed,the porosity was good.In the central and southern areas,high porosity values appeared where sandbodies with high compositional and textural maturity.Benefit high porosity thick sandstones were developed in the northern and eastern of river belts of the study area.