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S88及TS1井是塔河油田钻遇下古生界巨厚白云岩地层的典型钻井。对这2口井的岩样进行岩心观察、矿物鉴定、流体包裹体测温及地球化学研究表明,S88井奥陶系蓬莱坝组及TS1井寒武系下丘里塔格组白云岩地层除受原地盆地流体的影响外还可能存在深部热液流体的影响,流体性质以高温、富87Sr且携带热化学硫酸盐还原作用产物(H2S和CO2)的酸性流体为主。热液流体的运移导致这2口井深部储层次生溶蚀孔洞的发育,使得储集物性得到改善。研究还表明,这2口井疏导层的存在为深部热液流体的向上运移及进入储层提供关键通道。S88井热液流体对储层的影响主要受控于岩相和裂缝的发育程度,白云岩段储层好于灰岩段,裂缝发育段储层优于不发育段;TS1井白云岩储层的发育主要受控于岩性组合,下部井段的膏盐层与白云岩层的共生可能是其岩石物性优于上部纯白云岩井段的主要原因。
S88 and TS1 wells are typical wells drilled by the Paleozoic giant dolomite in the Tahe oilfield. The core observation, mineral identification, fluid inclusion temperature measurement and geochemistry of these two wells show that the Ordovician Penglai Dam S80 and the Cambrian Lower Huliqitag Formation of TS1 well are dominated by In addition to the influence of fluids in the in-situ basins, there may be deep hydrothermal fluids, which are characterized by high-temperature, 87Sr-rich acidic fluids carrying thermochemical sulfate reduction products (H2S and CO2). The migration of hydrothermal fluids led to the development of secondary dissolution pores in the deep reservoirs of these two wells, which resulted in the improvement of reservoir properties. The study also shows that the presence of the drainage layer in these two wells provides a key channel for the upward migration of deep hydrothermal fluids and their entry into the reservoir. The influence of hydrothermal fluids in S88 well is mainly controlled by the development of lithofacies and fractures. The dolomite reservoir is better than limestone reservoir and the fracture development reservoir reservoir is superior to undeveloped reservoir. TS1 well dolomite reservoir Is dominated by lithologic assemblages. The symbiosis of the gypsum salt and dolomite formations in the lower part of the well may be the main reason for its superior petrophysical properties over the upper pure dolomite well.