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随着塔中地区下古生界碳酸盐岩油气勘探地持续深入,分别在野外露头,塔中地区相关探井奥陶系储层中发现有萤石、闪锌矿、天青石、重晶石、硬石膏、焦沥青及热液石英等一系列热液矿物及其组合,越来越多的地质资料表明热液岩溶储层可能是塔里木盆地下古生界碳酸盐岩油气勘探中被忽视的一个重要储层类型。通过总结近6年大量的针对野外露头热液岩溶现象地实地观察测量,以及通过对塔中82井区—24井区奥陶系储层发育段大量的岩石薄片观察、矿物能谱测定、地层水锶同位素测试,断裂性质的分析,深入研究热液溶蚀流体的活动特点以及对形成优质储层的控制作用,最终建立了热液岩溶储层的地质模型。研究表明,热液矿物主要沿断裂伴生的构造溶蚀缝和溶蚀孔洞发育,断裂是热液运移的主要通道,是形成优质储层的重要控制因素。塔中地区沿海西期走滑断裂附近的奥陶系灰岩将广泛发育热液溶蚀改造形成的储层,为塔中西部上奥陶统沿走滑断裂向内带拓展油气勘探打下了基础。
With the continued exploration of the Lower Paleozoic carbonate rocks in Tazhong area, fluorite, sphalerite, celestite, barite , Anhydrite, pyrophyllite and hydrothermal quartz, and more and more geological data show that hydrothermal karst reservoirs may be overlooked in the Lower Paleozoic hydrocarbon exploration in the Tarim Basin An important reservoir type. By summarizing a large number of field observation measurements of the outcrop hydrothermal karst in recent 6 years, and by observing a large number of thin sections of the Ordovician reservoir in the Tazhong 82 well block, mineral energy spectrum determination, Water and strontium isotope test, the nature of the fracture analysis, in-depth study of hydrofluid fluid activity characteristics and the formation of high-quality reservoir control, and ultimately established a geological model of hydrothermal karst reservoir. The results show that the hydrothermal minerals are mainly developed along fault-structure tectonic dissolution fractures and dissolved pores, and fracture is the main channel for hydrothermal migration, which is an important controlling factor for the formation of high-quality reservoirs. The Ordovician limestone near the coastal strike-slip faults in the Tazhong area will extensively develop the reservoirs formed by hydrothermal dissolution alteration, laying a foundation for the extension of oil and gas exploration along the strike-slip faults in the upper central Tarim Basin.