ZT 1井钻探分析及周口TZ-SQ凹陷勘探思考

ZT 1 well drilling analysis and speculations on Zhoukou TZ-SQ sag exploration

位于南华北盆地周口坳陷中部凹陷带TZ-SQ凹陷的ZT 1井实钻结果与前人研究成果存在着巨大差异,颠覆了对该区构造的传统认识。通过对ZT 1井所在地区生烃条件、储集条件、沉积环境的分析,认为ZT 1井所在区块K1统沉积了巨厚烃源岩,这些烃源岩生油条件中等,处于成熟到高成熟阶段;实钻结果显示ZT 1井目的层系储集岩物性差,但微孔隙发育且存在裂缝性储渗空间。通过ZT 1井K1统地层砂泥比、重矿物、纵向与横向岩性变化的对比分析,判断TZ-SQ凹陷在K1世可能是一个整体湖盆,中部构造带在K1世为沉积沉降中心,为湖盆中央或接近湖盆中央,并非传统认识的分隔TZ-SQ凹陷南部与北部的凸起。基于实钻资料带来的新认识,提出加强古构造研究、寻找有利相带、兼顾孔隙性储集层与裂缝性储集层、以气为主、油气并举、注重常规油气层勘探的同时兼顾致密油气与页岩气勘探等勘探建议。

The real-drilled results of ZT 1 well,located in TZ-SQ sag of the central Zhoukou depression zone,southern North China Basin,are greatly different from the previous research results,which subverts the traditional understanding of the structure in this area.Through the analysis of hydrocarbon generation conditions,reservoir conditions and depositional environment in the area where the ZT 1 well is located,it is considered that the K1 series in the block where ZT 1 well is located has deposited hugely thick source rocks.These source rocks have medium oil generation conditions and are in mature to high mature stage.The real-drilled results show that the physical properties of reservoir rocks in the target series of strata of ZT 1 well are poor,but the micro pores are developed and there is a fractured storage space.Through the analysis of the ratio of sand to shale,heavy minerals,and comparison of longitudinal and lateral lithology changes for K1 series strata of ZT 1 well,it is concluded that TZ-SQ sag may be a whole lake basin in K1 epoch.The central structural belt was the deposition and subsidence center in the K1 epoch,which was the center or close to the center of the lake basin,rather than the uplift separating the south and north of TZ-SQ sag as traditionally recognized.Based on the new understanding brought by real-drilled data,the paper puts forward some exploration suggestions,such as strengthening the study of paleostructure,searching for favorable facies belts,taking into account both porous and fractured reservoirs,giving priority to gas and developing oil and gas at the same time,while focusing on conventional hydrocarbon reservoir exploration,tight oil and gas and shale gas exploration are also considered.