高含凝析油凝析气藏中油环判别方法探索应用

Application of Oil Rim Identification in Condensate Gas Reservoirs with High Condensate Content

油环的判别是凝析气藏开发的基础,特别是对于高含凝析油凝析气藏,判别是否存在油环尤为重要。判别油环存在有两大类方法,即实际资料分析对比判别法和经验统计判别法。常用的经验统计判别法包括C_(5)^(+)含量法、C1/C_(5)^(+)比值法、组合参数φ1法、秩类法、两组合参数Z因子法和四组合参数法。某深层构造高部位高含凝析油凝析气应用常用的经验统计判别法进行油环判别,除了四组合参数判别为油藏,其余方法皆判别为高含凝析油凝析气藏带油环。构造低部位后钻评价井MDT取样取到挥发油样,实际证明了此高含凝析油凝析气藏带有油环。应用经验统计法判别高含凝析油凝析气藏油环存在的结果表明:绝大多数常用的经验统计判别法适用于高含凝析油凝析气藏的油环判别,只有四组合参数不适用,主要原因系高含凝析油凝析气C_(2)^(+)摩尔量超过30%,需结合其他经验统计法共同判别。

The identification of oil rim is the basis for the development of condensate gas reservoirs, and there is oil rim or not is particularly important especially for that with high condensate content.There are two kinds of methods of identifying oil rim,namely,the discriminant method of actual data analysis and comparison and the one of empirical statistics.The commonly used empirical statistical discriminant methods include C_(5)^(+)content method,C1/C_(5)^(+)ratio method,combined parameter φ1 method,rank class method,two combined parameter Z-factor method and four combined parameter method.The method of empirical statistics is used to discriminate oil rim for condensate gas in high position of deep structure.It is discriminated as oil reservoir by the method of four combined parameters,and as condensate gas reservoirs of oil rim with high condensate content by other three methods.Volatile oil samples were found in the MDT samples of the appraisal well drilled at the low position of the structure,which prove that the oil rim exists in the condensate gas reservoirs with high condensate content.The oil rim in the condensate gas reservoirs with high condensate content may be identified mostly by the empirical statistics method.It shows that the most commonly used empirical statistical methods are suitable for discriminating the oil rim in the condensate gas reservoir with high con-densate content except for four combined parameters method,and the main reason is more than 30% of C_(2)^(+)molar content in the condensate gas with high condensate content.The four combined parameters method should be applied together with other empirical statistics methods.