准噶尔盆地车排子地区侏罗系下切谷充填特征及地质意义

Infilling characteristics of the jurassic incised valley and its geological significance in the Chepaizi area of the Junggar Basin

金杰华 王永诗 操应长 韩宏伟 陈林 王艳忠

中国石化胜利油田分公司物探研究院，山东 东营 257022 胜利石油管理局博士后科研工作站，山东 东营 257000 中国石化胜利油田分公司，山东 东营 257015 中国石油大学（华东），山东 青岛 266580 中国石化胜利油田分公司勘探开发研究院，山东 东营 257015

Geophysical Research Institute, Shengli Oilfield Company, SINOPEC, Dongying 257022, China Working Station for Postdoctoral Scientific Research, Shengli Petroleum Administrative Burea, SINOPEC, Dongying 257000, China Shengli Oilfield Company, Dongying 257015, China China University of Petroleum, Qingdao 266580, China Exploration and Development Research Institute, Shengli Oilfield Company, SINOPEC, Dongying 257015, China

综合运用地震、测井、录井、钻井岩心及薄片等资料，开展准噶尔盆地西缘车排子地区下切谷沉积相类型及充填特征分析。研究表明，车排子地区发育单一型、多分支河道型及复合型下切谷，下切谷横剖面主要呈“V”形、“U”形及碟形。下切谷内部充填的沉积砂体主要为河流相、坡积扇相及支流扇相。河流相岩性以砂砾岩、含砾砂岩、含砾泥岩为主，颗粒呈次圆状，分选性中等—好，成熟度相对较高，测井曲线主要表现为低幅度齿化箱形。坡积扇相岩性以角砾岩为主，颗粒支撑结构，分选性差，砾石粒径变化大，主要分布在2~6 mm，最大可达数十厘米，呈棱角—次棱角状，杂基主要为砂和泥，成熟度低，基本不显示层理，地震上主要表现为空白反射地震相及杂乱反射地震相，测井响应主要为箱形或齿化箱形。支流扇相岩性以砂砾岩及含砾泥质砂岩为主，砾石粒径主要分布在2~4 mm，可见厘米级砾石，呈次棱角—次圆状，分选性相对较差，颗粒支撑结构，录井上表现为底部砂砾岩、顶部砂岩的特征，测井曲线表现为弱齿化箱形和钟形。下切谷中央主要发育河流相砂体，两侧以叠覆堆积的形式与坡积扇和支流扇交互堆积，下切谷河流相砂体是储层发育的有利区，坡积扇和支流扇不利于储层发育，其杂基含量高，胶结作用强烈，可作为储层的侧向封堵层。

Abstract: By comprehensively using the data of seismic exploration, well logging, drilling core and thin section, the sedimentary facies types and infilling characteristics of the incised valley in the Chepeizi area located on the western margin of the Junggar Basin were analyzed. The results showed that the incised valley was divided into single type, multi?鄄branch channel type and compound type, the cross section of which presented "V" shape, "U" shape and disk shape. Sedimentary sand body infilled in the incised valley were mainly fluvial facies, talus fan and alluvial fan. Fluvial facies were mainly composed of conglomerate, pebbly sandstone and pebbly mudstone, which were featured by sub?鄄circular particle, medium to good sorting and relatively high maturity. The logging curves mainly showed low?鄄amplitude toothing box shape. Talus fan was predominantly composted of breccias with granular supporting structure and poor sorting. Gravel size varied mainly from 2 mm to 6 mm, the maximum of which reached up to tens of centimeters. These components presented angular shape to sub?鄄rounded shape. The matrix was mainly observed as sand and silt with low maturity. No bedding was observed in the talus fan. The seismic facies were distinguished as blank or clutter, and the logging curve showed box shape or gear box shape. The alluvial fan was mainly composed of glutenite and gravel-bearing argillaceous sandstone. The gravel size ranged from 2 mm to 4 mm, and centimeter?鄄scale gravel can also be seen in cores. The particles presented sub angular shape and sub circular shape with a relatively poor sorting and granular supporting structure. The logging lithology was characterized by the glutenite on the bottom and sandstone on the top. The logging curves showed weak tooth box shape and bell shape. Fluvial facies were mainly developed in the central part of the incised valley. The talus fan and alluvial fan were deposited interactively on both sides of the valley in the form of overlapping accumulation. Fluvial sand bodies are favorable areas for developing reservoirs, while talus fan and alluvial fan are not conducive to the development of reservoirs due to their high matrix content and strong cementation. The talus fan and alluvial fan can be acted as the lateral sealing layer of reservoir.

10.6056/dkyqt202206014