频率域薄储集层预测技术在煤系地层中的应用  

Application of Thin Reservoir Prediction Technology Based on Frequency Domain in Coal Measure Strata

作　　者：冯昕鹏 王涛[2] 白志涛 聂万才 何争光 FENG Xinpeng;WANG Tao;BAI Zhitao;NIE Wancai;HE Zhengguang(Changqing Branch of GRI,BGP,Xi’an,Shaanxi 710021,China;PetroChina Changqing Oilfield Company,Yihuang Natural Gas Division,Xi’an,Shaanxi 710018;PetroChina Changqing Oilfield Company,No.1 Gas Recovery Plant,Xi’an,Shaanxi 710000,China)

机构地区：[1]东方地球物理公司研究院长庆分院,西安710021 [2]中国石油长庆油田分公司宜黄天然气项目部,西安710018 [3]中国石油长庆油田分公司第一采气厂,西安710000

出　　处：《新疆石油地质》2021年第5期605-611,共7页Xinjiang Petroleum Geology

基　　金：国家科技重大专项(2017ZX05069)。

摘　　要：下二叠统太原组和中二叠统山西组山2段是鄂尔多斯盆地东部气田致密岩性气藏的主要产气层,分别属于海陆过渡相和三角洲前缘相,砂体薄,横向规模小。太原组—山西组发育多套煤层,以山2段中下部4+5号煤层及太原组底部9号煤层最发育。煤岩波阻抗低,与高波阻抗砂泥岩地层形成强反射,屏蔽了砂泥岩之间的弱反射,应用叠前反演、地震属性等常规方法难以有效预测薄砂体。建立研究区目的层段砂泥岩地质模型,通过模型正演和时频分析方法对比发现,广义S变换能根据信号频率变化自适应调节时频分析时窗,具有更高的分辨率;实际应用中,首先压制煤层强反射,在此基础上采用广义S变换对研究区的薄储集层进行预测,井震符合率高,有效解决了研究区煤层背景下的薄储集层预测难题。The Lower Permian Taiyuan formation of marine-continental transitional facies and the second member of the Middle Permian Shanxi formation(Shan 2 member for short)of delta front facies are primary natural gas pay zones in eastern Ordos basin.They are tight lith⁃ologic gas reservoirs characterized by thin sand body and small scale.In the Taiyuan formation and the Shanxi formation,there are several coal seams,among which No.4+5 coal seam in the middle-lower Shan 2 member and No.9 coal seam at the bottom of the Taiyuan forma⁃tion are most developed.With lower wave impedance,coal seams show stronger reflection than sandstone and shale with higher wave im⁃pedances,so that the former shield the weak reflection from the latter,making it difficult to effectively predict thin sand bodies by using conventional methods such as prestack inversion and seismic attributes.On the geological model of sandstone and shale reservoirs in the target intervals in the study area,we carried out forward modeling and time⁃frequency analysis,and found that generalized S⁃transform could adaptively adjust time⁃frequency analysis window according to signal frequency,and its resolution was higher.In the actual applica⁃tion,strong reflections from coal seams were suppressed,then generalized S⁃transform was performed to predict thin reservoirs in the study area.The result shows a high coincidence rate between seismic data and well logging data.The method can effectively predict thin reser⁃voirs on the background of coal seams.

关 键 词：鄂尔多斯盆地 薄储集层预测 煤系地层 强反射压制 频率域 时频分析 广义S变换 

分 类 号：P631.445.91[天文地球—地质矿产勘探]