Development of Karst Formation in Area 4 of Tahe Oil field

The main oil-bearing formation of Area 4 of Tahe oilfield is in Yingshan Group of Ordovician consisted of thick pure limestone. The types of the pore space contain the pore, fissure, cave as well as fracture formed by solution collapse. The primary porosity and tectonic fracture are of poor growth. Therefore, the formation growth is mainly controlled by hydraulic units of the palaeo-karst. There are three palaeo-hydraulic zones: vadose zone (including infiltration sub-zone and percolation sub-zone), phreatic zone and tranquil zone. They are identified by retrieving the palaeo-geographical karst environment. The pore space of the infiltration zone is mainly solution fissures, small solution cavities and solution pores. The growth and lateral connection of the formation are favorable. The reservoir/formation ratio is 0.54. The pore space of the phreatic zone developed large size cavities and fractures related to cave collapse. The height of the cavity can reach 71m. The fractures by collapse have a influencing range of more than 100m, and its reservoir/formation ratio is 0. S1. But the lateral connection is unfavorable. The percolation subzone and the tranquil zone are of relatively poor growth with the reservoir/formation ratio less than 0.3.     

塔河油田奥陶系潜山碳酸盐岩储层特征及测井评价技术

新疆塔河油田储集层为下奥陶统风化壳，以裂缝溶洞型储集层为主。影响储集空间性能的主要因素是构造应力和风化淋滤作用。该类储集层的特点是储集空间类型多，复杂，非均质性极强，储集层评价困难。从基础测井资料入手，分析了该类储集层的储层特征，并运用岩心分析技术、交会图技术、经验公式等方法建立了储层孔、渗、饱参数的解释模型，利用Petrophysics软件包实现了裂缝溶洞型潜山油藏的储层参数测井定量解释，初步形成了该类储集层的测井评价方法，实际应用效果比较显著。     

塔河油田奥陶系潜山油藏油水关系分析

油水关系特征及油水分布状况是油藏描述的重要内容之一。正确认识油藏的油水分布特征,对于油藏的方案编制、注水开发等起着至关重要的作用。潜山油藏不同于碎屑岩油藏,由于其特殊的储层结构以及储集空间类型,导致该类油藏中流体空间分布更具复杂性。以塔里木盆地塔河油田奥陶系油藏为例,根据单井以及井组的开发特征,结合该区储层分布特点,总结归纳了缝洞型碳酸盐岩潜山油藏油水关系模式,主要有普通式、隔油式、隔水式、复合式以及纯油式;针对每一类模式,实例分析了典型井以及井组的生产或见水特征。     

塔河油田4区奥陶系油藏缝洞单元的划分

缝洞单元目前广泛应用于潜山油蒇连通状况研究,对于即将实施注水开发的潜山油藏来说,缝洞单元的划分尤为重要,其目的就是认清井闻的储层连通关系,保证注水开发效果.应用塔河油田4区的动态资料、静态资料,从流体性质、压力系统特征和井间储层连通关系,对近60口井进行了缝洞单元的划分.全区共划分了31个缝洞单元,并根据缝洞单元的连通范围及天然能量大小,将其划分为Ⅰ、Ⅱ、Ⅲ共3类,其中Ⅰ类1个,Ⅱ类7个,Ⅲ类23个,并在该划分结果基础上,实施注水开发,取得了较好的开发效果,验证了划分结果的正确性.