Enhance Recovery By Numerical Modeling Of Nitrogen Injection In Ultra-low Permeabiltiy Oil Field

Shanbei oil fields are low permeability or ultra-low permeability oil fields. It’s physical property is complicated and aeolotropism is powerful. Although some valid treatments are took, such as injecting water, but water quality requirement and cost are high, pressure difference is great. This cause casing deformation, casing failure, water well’s low availability and some reservoir flooding failure. Moreover, low permeability reservoir’s shale content is high, water sensitivity is powerful, this can create unrecoverable damage, this lead most part crude oil left-in-place. Considering the situation, gas drive is fit for low permeability reservoir at the moment, gas drive measures’gas is different, the oil displacement mechanism is different too. The CO2and hydrocarbon gas miscible displacement is effective, but the lack of this resource lead to these measurements’use and spread. In twentieth Century eighty years later, because the N2’s wide source, low price, no corrosion, no pollution and the unique superiority, the nitrogen flooding has became gas drive’s new technique and method. Especially for low permeability reservoir, condensate gas reservoir and steep structural reservoir, nitrogen flooding has achieved very god results. From50time begin to study until now, Reservoir numerical simulation technology has developed into a relatively mature technology. In oilfield development programming and identify, oil production measures of adjustment and optimization, and to improve oil recovery, this has gradually become an indispensable main research method. Relative to the field experiment,it is low cost, low risk. Therefore, exploring the N2injection EOR methods is meaningful to improving in ultra low permeability reservoir development effect in Shanbei oil field and sustainable development.This passage focuses on the application of the EOR technology—injecting nitrogen towards ultra-low permeability reservoir. Author chose the western part of Danba block as the research area. specific numerical model was built employing the real production data. At the same time, author also conducted PVT test on nitrogen and crude oil and the relative miscibility pressure study. Then,3D geologic model was built and it was used to simulate gas injection and water alternating gas injection. Result shows water alternating gas injection is the better choice, for it can enhance the recovery efficiency as to4.26%. This passage provides a positive measure for injection nitrogen technology.