一种新型增长曲线预测气田开发指标的方法

A METHOD OF PREDICTING GAS FIELD DEVELOPMENT INDEXES BY A NEW INCREASE CURVE

对于气田，凡是能满足如下条件，即当ｔ＝０时，Ｇｐ＝０，以及当ｔ→∞时，Ｇｐ＝ＧＲｍａｘ的函数表达式，统称为用于气田开发指标预测的增长曲线。提出了一种预测气田开发指标的新型的增长曲线：Ｇｐ＝ＧＲｍａｘｂｔ－１ｂｔ＋ａ，推导了这种增长曲线的Ｑｇ—ｔ、ｔｍ、Ｑｇｍａｘ以及ＲＰＲ的计算公式。用图形研究了这种增长曲线Ｑｇ—ｔ关系的变化特点。根据研究发现了一个重要的关系：气田产量达到最大值Ｑｇｍａｘ时对应的累积产气量Ｇｐ（Ｑｇｍａｘ）与最大可采储量ＧＲｍａｘ的比值恒等于ａ－１２ａ，即Ｇｐ（Ｑｇｍａｘ）ＧＲｍａｘ≡ａ－１２ａ，称为Ｇｐ＝ＧＲｍａｘｂｔ－１ｂｔ＋ａ型增长曲线预测气田开发指标的ａ－１２ａ准数。提出了根据实际资料计算ＧＲｍａｘ、ｂ和ａ等参数的重复线性回归法。相国寺气田的计算实例表明这种增长曲线实际应用的重大价值。

The functional expression,which can satisfy the following conditions,i.e.if t =0,then G p=0;if t =∞,then G p= G Rmax is called an increase curve used for predicting gas field development indexes. In the paper,a new increa curve of G p= G Rmax b t-1 b t-a mould for predicting gas field development indexes is proposed ,the formulas of Q g vs t , t m, Q gmax and RPR(reserves production ratio)of the increaese curve are derived and the change of Q g vs t of the increase curve is studied by drawing. In accordance with the research, an important relation has been found,i.e.while the gas field,production reaches the maximum ( Q gmax ),the relevant cumulative gas production G p ( Q gmax ) to the maximum recoverable reserves G Rmax ratio is identi cally equal to a-12a ,i.e. G p( Q gmax ) G Rmax ≡ a-12a ,which is called a-12a criterion for predicting gas field development indexes by the G p= G Rmax b t-1 b t+ a mould increase curve. The method of repeated linear regression is proposed for calculating the parameters as G Rmax , b and a ,etc.,according to actual data. Through a calculation for Xiangguosi gas field,it is shown that this increase curve is of great useful value in practice.