王官屯油田官142地区中生界地层特征

Formation Characteristics of Mesozoic in Guan142 Area of Wangguantun Oilfield

王官屯油田地处河北省沧县王官屯乡境内,区域构造位置为黄骅坳陷南区孔店构造带的西南端,处于孔东断裂带两侧。根据钻录井特征、地球物理响应特征,结合区域地层对比,将王官屯油田官142地区中生界地层划分为中下三叠统、中下侏罗统、上侏罗统-下白垩统三套旋回。通过对该区地层特征的分析,认为中下三叠统以棕红、紫红色粉细砂岩和泥岩互层为主;中下侏罗统下部主要为暗色泥岩夹砂岩,上部为一套巨厚砂砾岩,并作为中生界油藏主要储集层;上侏罗统-下白垩统发育紫红色砂岩及安山岩。通过分析各时期的构造运动特征,认为印支运动以整体抬升为主,发育了三叠系地层;燕山早期以走滑和挤压为主,盆地规模较小,发育中下侏罗统的河湖相沉积;燕山中期火山活动强烈,发育火山物质为主的晚侏罗世-早白垩世地层;燕山晚期该区整体抬升遭受剥蚀,缺失上白垩统地层。而喜山时期的升降运动对中生界油气成藏具有重要意义。

Wangguantun oilfield locates in Wangguantun country,Cang county,Hebei province.Its regional structural position is the southwestern end of Kongdian structural beh in the south region of Huanghua depression situated at both sides of Kongdong fracture belt.According to drilling and mud logging features and geophysi- cal response characteristics,the Mesozoic formations of Guan142 area in Wangguantun oilfield are divided into three sets of cycle in middle-lower Triassic ,middle-lower Jurassic ,upper Jurassic-lower Cretaceous combined with regional stratigraphic correlation.By analyzed the formation characteristics in this area,the middle-lower Triassic formations are dominated by henna and fuchsia fine sandstone-sihstone and mudstone interbed;there are mainly dark mudstone and sandstones in the lower part,and a set of thick glutenite as the important reservoirs of the Mesozoic in n the upper part of the middle-lower Jurassic;mauve sandstones and andesite developed in upper Jurassic-lower Cretaceous formations.After the characteristics of tectonic movement in each period are analyzed,it is considered that the main overall uplift in Indochina movement causes the Triassic formation;there were strike-slip and extrusion structure in early Yanshan movement and fluvial facies in small-scale basin developed in the middle-lower Jurassic;intense volcanic activity in the mid-Yanshan causes late Jurassic-early Cretaceous formations with volcanic material dominated;overall uplift and denudation in later-Yanshan movement in this area cause the lack of Cretaceous strata.The elevating movement in the Himalayan period is important to hydrocarbon accumulation of Mesozoic era.