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塔里木盆地寒武系发育大规模优质台地边缘相礁滩型白云岩储层,油气勘探前景广阔。通过对柯坪地区7条下寒武统野外露头剖面的精细测量及室内岩石薄片观察和物性测试,明确了该区下寒武统肖尔布拉克组的岩石地层和沉积储层特征,并通过剖面对比厘清了台缘带内部沉积结构和储层空间展布规律,最终建立了台缘礁滩型白云岩沉积储层模型。研究表明,该区肖尔布拉克组可分为上、下2段,肖下段以泥粉晶白云岩为主,为缓坡型台地边缘潮下带低能沉积;肖上段可划分为3个亚段,以藻纹层白云岩、微生物礁白云岩、球粒白云岩和叠层石白云岩为主,为弱镶边型台地边缘高能沉积。台缘带白云岩储层的发育受沉积相控制,主要发育在肖上二亚段和肖上三亚段的颗粒滩相白云岩中,储集空间以溶蚀孔和晶间孔为主,孔隙度范围为0.6%~9.02%,平均为5.5%,储层平均厚度为30~40m,在垂直台缘带方向展布宽度在25km以上。
The Cambrian of the Tarim Basin has developed large-scale, high-quality platform-edge dolostone reservoirs with reef-shoal type dolomite reservoirs with broad prospects for oil and gas exploration. Based on the detailed measurements of seven outcrops of the Lower Cambrian in Keping area and the observation and physical testing of the in-situ rock slices, the lithostratigraphy and sedimentary reservoir characteristics of the Lower Cambrian Shoalbulak Formation in this area are confirmed The cross-section comparison clarifies the sedimentary structure and the spatial distribution of reservoirs in the platform margin, and finally establishes the dolomite sedimentary reservoir model of the platform margin reef-shoal type dolomite. The study shows that the Shoalbulak Formation in this area can be divided into upper and lower 2 sections, while the lower section of this section is dominated by mud dolomite dolomite, which is the low energy sedimentary subtidal zone with gentle slope. The upper section can be divided into 3 sub-sections , Algae layer dolostone, microbial reef dolomite, pelletizers dolomite and strata dolomite mainly for the edge of weakly striped platform high-energy deposition. The development of dolomite reservoirs in the margin zone is dominated by sedimentary facies and mainly occurs in the dolomitic facies dolostones of the Xiao Shang II section and the Xiao Shang Sanya section. The reservoir space mainly consists of dissolved pores and intergranular pores, while the porosity The range is from 0.6% to 9.02%, with an average of 5.5%. The average thickness of the reservoir is 30-40 m, and the width of distribution in the direction of vertical platform margin is more than 25 km.