亚期 meaning in English
substage
subage
Examples
- The faulting activity of this area is divided into two phases and four sub - phases
本区断裂活动分为两期四个亚期。 - And the most deposital velocity was 220 . 2mm / ka during c17 . 3n sub - period , which mainly occurred at the unloaded area in the front of the delta
其中在c17n ? 3n极性亚期内，最大沉积速率可达220 . 2mm / ka 。这主要发生在三角洲前缘的沉积物卸载区。 - The variations in trace element contents and ratios may hold up a mirror to the lake - level fluctuations and climatic changes , which , in turn , have exerted a direct and important effect on the sequence stratigraphic development . collectively , the reservoir rocks from the yanchang formation consist dominantly of the delta front subfacies subaqueous distributary channel and channel - mouth bar microfacies and delta plain subfacies subaerial distributary channel microfacies fine - grained feldspar sandstones and siltstones . the reservoir rocks have been subjected to three stages of diagenetic and porosity evolution : ( 1 ) the porosity reduction by the mechanical compaction and chemical pressure solution during the early diagenetic stage ; ( 2 ) the porosity increase by the dissolution during the a substage of the late diagenetic stage , and ( 3 ) the porosity reduction by the cementation and filling during the b substage of the late diagenetic stage
系统的储层特征研究表明，该区延长组储层成因类型主要为三角洲前缘水下分流河道、河口砂坝及三角洲平原水上分流河道微相细粒长石砂岩、粉砂岩；储层岩石经历了压实，胶结，溶蚀等成岩作用，历经早成岩机械压实和化学压溶孔隙缩小期、晚成岩a亚期溶蚀作用孔隙扩大期及晚成岩a亚期( b亚期)胶结充填孔隙缩小期三个成岩-孔隙演化阶段；储层物性总体上具有较低孔渗、低孔渗的特点，孔隙类型主要为粒间溶孔、残余粒间孔隙、粒内溶孔、晶间孔及晶间溶孔，裂缝不发育，储集岩排驱压力和中值压力较高，孔隙结构类型以细小孔-微孔隙，微细喉-微喉型为主。