基于岩石物理相研究特低渗透油藏宏观剩余油分布

对于低渗、特低渗透储层,由于其所受沉积、成岩和构造等一系列作用的影响,致使该类油藏的储集性能和渗流结构存在较大的差异,储层具有较强的非均质性,剩余油分布异常复杂;而储层的非均质性在一定程度上控制着该类油藏的剩余油分布。因此,以延长东部某特低渗透非均质油藏长6_1~1油层为例,提出利用岩石物理相研究该类非均质油藏宏观剩余油的方法。通过建立岩石物理相定量综合评价指标体系,将储集层分为几种不同类别的岩石物理相。针对不同类别岩石物理相分别计算单井储量、标定技术采收率以及研究剩余可采储量分布。研究结果表明岩石物理相是控制该类油藏剩余油分布的基本单元,同种岩石物理相内剩余油的分布规律相似,从而阐明了有利的岩石物理相剩余油潜力分布的特点,实现了宏观剩余油的研究从笼统研究到精细化研究的转化,为油区后期剩余油的挖潜提供了可靠的地质依据。同时也为同类型的特低渗透非均质油藏剩余油潜力分布的研究提供了新颖的研究思路和方法。

A study on macroscopic remaining oil distribution of ultra-low permeability oil Reservoir using petrophysical facies

For low, extra-low permeability reservoir, it is the influence of sedimentation, digenesis, construction and a series of effects that result in the major difference in the reservoir property and percolation structure of the reservoir, the reservoir has strong heterogeneity and its remaining oil distribution is very complicated, whereas the heterogeneity controls the remaining oil distribution to some extent. Therefore, this article takes a extra-low permeability heterogeneity reservoir in the eastern part of Yanchang oilfield for example, making use of petrophysical facies to study By establishing petrophysical facies ration comprehensive assessment target system, dividing the reservoir into several kind of petrophysical facies. For each kind of petrophysical facies, the article calculates single well reserves, demarcate technology recovery efficiency and study residue recoverable reserve distribution respectively. The research results show that petrophysical facies are elementary units that control the remaining oil distribution of this kind of reservoir. The same kind of petrophysical facies has the same remaining oil distribution law, thereby illuminating advantageous petrophysical facies remaining oil potential distribution characteristics and realizing from general research to elaborate research about macroscopic residual oil, it provides reliable geological basis for remaining oil potential tapping at the later period, meanwhile, it provides a neoteric research thought and method for remaining oil potential distribution research of the same type of extra-low permeability heterogeneous reservoir.