塔里木盆地哈6区块奥陶系碳酸盐岩古岩溶储层特征识别及地质建模

塔里木盆地哈6区块奥陶系储层为碳酸盐岩古潜山岩溶缝洞型储层,其储集空间类型包括生物体腔孔、生物钻孔、粒内溶孔、铸模孔、溶蚀孔洞、断层和裂缝、未塌陷的溶洞洞穴系统、塌陷型溶洞—洞顶缝系统等。针对哈6区块奥陶系碳酸盐岩塌陷型溶洞—洞顶缝系统建立了缝洞体形成模型、井震模型、地震正演模型和油气藏模型,提出地震"串珠状"反射体实为大型缝洞体的反映,而大量的地下暗河溶洞段目前的地震技术仍然无法有效识别。针对洞顶缝进行了定义,提出溶洞上部塌陷形成的洞顶缝系统是哈6区块奥陶系碳酸盐岩主要的油气产层,其次塌陷型溶洞体本身也是主要的油气产层,但可通过洞顶缝系统采出其中的油气,因此洞顶缝概念的提出对钻井、录井和油气酸化压裂测试和试采具有重要意义。

Paleokarst Reservoir Recognition and Geology Modeling of Ordovician Carbonate of Block Ha 6 in Tarim Basin

The Ordovician carbonate reservoir in Block Ha 6 is characterized by karst fracture-cavern in buried hill. The reservoir space includes visceral cavity, burrow pore, intragranular dissolution pore, moldic pore, faults, fracture, cave system and collapsed cavern-ceiling crackle system. In this paper, series models were built on the basis of collapsed cavern-ceiling crackle system in Block Ha 6, fracture-cavern model, well logging-seismic integrated model, seismic forward model, and reservoir model were developed. "Moniliform"reflection of seismic was actually great collapsed cavern and fracture, but the subsurface river system could not be recognized effectively by current seismic technology. Ceiling crackle was defined. The ceiling crackle caused by top cave collapse was main oil and gas production interval in Block Ha 6. Secondly, the break-out dome was also oil and gas production interval; oil and gas could be produced through ceiling crackle. Therefore, the concept of ceiling crackle was very important to well drilling, well logging, acid fracturing test and production test.