基于砂体构型精细刻画潮坪砂坝优质砂体——以大牛地气田D17井区太原组2段为例

Configuration-based fine description of high-quality sand bodies in tidal-flat bar—Taking the tight sandstone reservoir in the 2ndmember of the Taiyuan Formation in D-17 wellblock in Daniudi gasfield as an example

以大牛地气田未开发区（ D17井区）太原组2段潮坪沉积为研究对象，基于测井、岩性等特征分析，对潮坪砂坝进行了精细刻画，共识别出了砂坝主体、砂坝侧翼及砂坝侧翼叠置3个沉积微相单元，并建立了沉积微相－岩相－测井相－物性－非均质性－试气成果响应模板。对比结果显示，砂坝主体微相岩性主要为（含砾）石英粗砂岩及岩屑石英砂岩，测井曲线具光滑箱形；砂坝侧翼微相岩性主要为中－细粒砂岩岩屑砂岩、岩屑石英砂岩，测井曲线为齿化箱形、齿化钟形以及漏斗形。根据砂体组合类型，区域上划分出了砂坝主体型砂体带与砂坝侧翼型砂体带。前者砂坝宽度为6～8 km，砂体平均厚度为14.5 m，砂地比平均值为0.53，平均渗透率为0.48×10－3μm2。后者砂坝宽度为4～6 km，砂体平均厚度为10.56 m，砂地比平均值为0.36，平均渗透率为0.36×10－3μm2。砂坝主体型砂体带砂体发育规模大，分布范围广，砂体物性好，中等非均质性，试气成果明显，应作为优先开发的地区。

Logging data and lithological analyses of the tidal-flat depositsin the 2 nd member of the Taiyuan Formation （ D-17 wellblock ） in the Daniudi gas field revealed three sedimentary microfacies：mainsandbar ,sandbar flanking and overlain sandbar flanking-.A response-template of sedimentary micro-facies-lithofacies-logging facies-physical property-heteroge-neity-gas test was also established .Correlation shows that the main sandbar is mainly gravel-bearing quartzose laterite and lithic quartz sandstone , corresponding to smooth-box type logging curves;and thelatter two are mainly medium-to fine-grained lithic sandstone and quartz sandstone , corresponding to dented box-and bell-shaped or funnel-shaped logging curves.Regionally,two belts were identified based on sand body assemblage types：sand body belt consisting main sand-bar and sand body belt consisting sandbar flanking .The former is 6-8 km wide,and has an average thickness of 14.5 m, an average net-to-gross ratio of 0.53 and an average permeability of 0.48 ×10-3μm2 .The latter is 4-6 km wide and has an average thickness of 10.56 m,an average net-to-gross ratio of 0.36 and an average permeability of 0.36 ×10-3μm2 .The former with its well developed and widely distributed sand bodies is considered to be a better development target as it has better physical properties and strong heterogeneity and good gas testing results .