评价气藏原始地质储量和原始可采储量的动态法——为修订的《SY/T 6098—2010》标准而作

Dynamic methods for estimating initial gas in-place and initial recoverable reserves in gas reservoirs--For the revised《SY/T 6098—2010》

气藏的原始地质储量(Initial gas in-place)和原始可采储量(Initial recoverable reserves)是对气藏的标量名称。我国将两者简称为地质储量(Gas in-place)和可采储量(Recoverable reserves)是不准确的。气藏的原始可采储量等于原始地质储量与采收率的乘积。由于不同地质与开发条件的影响,气藏的采收率是难以准确确定的,因而,利用动态法评价气藏的原始地质储量和原始可采储量就显得非常重要。用于评价气藏原始地质储量的动态法有:物质平衡法、压降法和弹性二相法;用于评价气藏原始可采储量的动态法有:产量递减法和预测模型法。根据气藏类型和拥有的动态数据情况,可以选用合适的方法进行原始地质储量、原始可采储量和剩余可采储量(Remaining recoverable reserves)的评价。由于剩余可采储量最具有实际意义,因此,国际上统一的年报均为剩余可采储量并简用reserves一词表示。剩余可采储量是原始可采储量与累积产量的差值,它与年度产量之比值为储采比(RPR)是重要参数。为此基于近年新的研究成果,对上述5种动态法进行完善推导,并通过实例加以应用。

Both initial gas in-place and initial recoverable reserves are two scalar terms for gas reservoirs.However,that they are abbreviated for"gas in-place"and"recoverable reserves"by some Chinese scholars is inaccurate.For one gas reservoir,the original geological reserves multiplied by the recovery factor equals the original recoverable reserves.Affected by different geological setting and development conditions,it is difficult to accurately determine the recovery factor.Therefore,it is very important to use some dynamic methods to evaluate the initial gas in-place and initial recoverable reserves.The evaluation methods for the initial gas in-place include material balance method,pressure drop method,and elastic two-phase method.While those for the initial recoverable reserves contain production decline method and prediction model method.According to reservoir type and available dynamic data,certain appropriate methods can be used to evaluate the initial gas in-place,the initial recoverable reserves,and the remaining recoverable reserves.Because the remaining recoverable reserves have the most practical significance,remaining recoverable,as an international and unified term abbreviated as reserves,is used in annual report.The remaining recoverable reserves are the difference between the original recoverable reserves and the cumulative production.The ratio of the remaining recoverable reserves to the annual production is an important parameter of the reserve-production ratio(RPR).Based on the latest achievement,these mentioned-above five dynamic methods are perfected and derived,and have been applied in practice.