基于PDA方法的缝洞型油藏井控储量评价

缝洞型碳酸盐岩油藏储集体类型多样,非均质性极强,且流动规律复杂,有效评价此类油藏的井控储量是调整油田开发方案、制定油井改造措施的基础。为了克服常规方法在计算此类油藏井控储量上的不足,文中提出了基于PDA方法的缝洞型油藏井控储量评价方法。该方法针对缝洞型油藏的特点,建立了地质静态特征与开发动态特征相结合的生产井类型划分标准,对不同类型井进行地质概念特征与流体流动模式的假设,利用PDA方法拟合多条典型曲线,通过井底流压的折算、井控范围的修正与拟稳态条件下PVT的计算提高曲线拟合精度,形成了缝洞型油藏井控储量的评价流程。研究结果表明,基于该方法评价的井控储量与实际认识相符,研究区剩余可采储量主要存在于Ⅰ,Ⅱ类井钻遇区,存在形式以洞顶剩余油为主,这些剩余可采储量是进一步调整挖潜的目标。

Well-controlled reserves evaluation of fracture vuggy reservoirs based on PDA method

Fracture-vuggy reservoirs have various types of reserv oir bodies with strong heterogeneity and complex flow law.Evaluating reserves of this reservoir effectively is the basis for adjusting the oilfield development plan and formulating oil well reconstruction measures.In order to overcome the shortcomings of the conventional method in the well-controlled reserves calculation of such type reservoir,we proposed a method for reserves calculation of fracture-vuggy reservoirs based on the PDA method.According to the characteristics of the reservoirs,the division standard of production well types combining the geological static and production dynamic characteristics was established.The conceptual of geological model and fluid flow pattern are assumed for different type wells,and many curves by PDA method were fitted.By improving the precision of curve fitting through converting the bottom hole pressure fron wellhead pressure,correcting the well control range and calculating the PVT parameters at the pseudo-steady state,the evaluation process for well-controlled reserves of such reservoir was established.The results show that the well-controlled reserves evaluation is in conformity with oilfield actual understanding,and the remaining recoverable reserves mainly exist in the drainage area of the well which drilled cave,fracture or solution pore with good connectivity.The remaining oil is in the form of ceiling residual oil and it is the target of further adjusting.