摘要
通过苏里格气田气层与非气层的岩石学特征、成岩作用、储集特征对比,分析了气层与非气层成岩相的差异。气层主要发育在粗粒岩屑石英砂岩溶孔成岩相和含泥粗粒岩屑石英砂岩溶孔相中,非气层则主要发育在含泥(中)细粒岩屑石英砂岩致密压实相和含泥(中)粗粒岩屑石英砂岩残余粒间孔相中。通过流体-岩石相互作用物理和数学模拟,在成岩演化中成岩阶段A期,大量有机酸的排出,溶蚀了苏里格气田储层凝灰质和长石等易溶组分,形成次生孔隙。由于沉积水体能量强弱差别、成岩作用的不同,中粗粒与细粒沉积物成岩演化途径不同,中粗粒沉积物次生孔隙发育,残余一定的原生孔隙,总孔隙度较大,易形成气层;细粒沉积物原生孔隙消失殆尽,次生孔隙少,总孔隙度很小,不易形成气层。
Based on a comparison in petrological features, diagenesis and reservoir characteristics between gas and non-gas reservoirs, the difference in their diagenetic facies is analyzed. Gas reservoirs are mainly developed in solution pore diagenetic facies of coarse-grained lithic quartzose sandstone and mud-bearing coarse lithic quartzose sandstone, whereas non-gas reservoirs mainly occur in compact diagenetic facies of mud-bearing medium-fine lithic quartzose sandstone and residual intergranular pore diagenetic facies of mud-bearing medium-coarse lithic fluid-rock interaction stage A of the middle quartzose sandstone. The mechanism of secondary pore formation was studied through physical and mathematic modeling. The results show the following mechanism: during diagenetic evolution phase, substantial organic acid was expulsed from source rocks and dissolved more soluble components such as tuff and feldspar in reservoirs of the Sulige gas field, thus forming secondary pores. The medium- and coarse-grained sediments and fine-grained sediments experienced different diagenetic evolution paths because of different energy intensities of their water bodies and their diagenesis. Medium- and coarse-grained sediments are easy to form gas reservoirs because their secondary pores are well developed, there are certain residual primary pores and the total porosity is high. However, fine sediments are not easy to form gas reservoirs because all their primary pores disappear, secondary pores are scarce and the total porosity is very low.
出处
《中国地质》
CAS
CSCD
2007年第2期276-282,共7页
Geology in China
基金
国家"973"项目(2001CB209103)资助。
关键词
鄂尔多斯盆地
苏里格
储层
成岩作用
孔隙演化
Ordos basin
Sulige gas field
reservoir
diagenesis
pore evolution
simulation