苏里格南部地区地震储层预测技术研究——以盒8段为例

Study of seismic reservoir prediction technology in the southern area of Sulige:a case of 8th member of Shihezi formation

苏里格南部地区是近年来勘探评价的重点地区.该地区上古生界沉积体系、下古生界奥陶系风化壳和古隆起台缘斜坡礁滩相沉积体系中均孕育着巨大的天然气产能,成为鄂尔多斯盆地天然气勘探开发的战略接替区.研究区目标层埋深大,储层厚度小;下古生界地层间波阻抗差异小,地层反射能量弱,分辨率低.针对这些难点,本文利用精细闭合差技术刻画目的层,采用波形特征分析、叠前反演等方法精细描述目的层的构造形态并预测砂体厚度,采用谐振法对目的层进行含油气检测.研究结果表明:研究区北部砂体厚薄变化相对较快,而南部总体砂体厚度变化较小.根据砂体厚度分布、有效砂厚与试气成果对盒8段进行有利区评价,有利勘探目标约为7505 km^2,其中Ⅰ类面积约为4729 km^2,Ⅱ类面积约为2776 km^2,预测结果为钻探井位提供了准确依据.

The southern part of Sulige is a key area for exploration and evaluation in recent years.In the areas,the Upper Paleozoic sedimentary system,the Lower Paleozoic Ordovician weathering crust and the paleo-uplift marginal slope reef-shoal facies sedimentary system are bred with huge natural gas reserves,which are expected to become strategic replacement areas for natural gas exploration and development in Ordos Basin.The target layer of the study area is deeply buried,and the reservoir thickness is small;the difference of wave impedance between the Lower Paleozoic strata is small,and the reflection energy is weak,also the resolution is low.To deal with these difficulties,the target layer is characterized by the fine mis-tie correction technique.And feature analysis,prestack inversion are taken to detailly describe the structure of the target layer and thickness prediction,aslo the Resonance method is used to hydrocarbon detection.The result shows that the sand thickness in the northern part of the study area changes relatively fast,while the change in the south is small.According to sand thickness distribution,effective sand thickness and gas test results,the favorable area of he 8 is evaluated,and the area is 7505 km^2,in which the area of classⅠis about 4729 km^2,and the area of classⅡis about 2776 km^2.The predicton result provides an accurate basis for drilling wells.