气藏动态储量计算中的几个关键参数探讨

A discussion on several key parameters of gas reservoir dynamic reserves calculation

传统的计算方法以物质平衡公式为基础,利用关井测压数据来计算动态储量。现今以"气井生产动态曲线特征图版拟合法"为主的动态计算储量方法,特点是利用流动压力计算气井动态储量。在对比分析这两种方法的基础上,结合国内外已开发气田动态储量计算实例,研究了关井测压数据和岩石有效压缩系数对动态储量计算的影响。结果表明,在没有关井测压资料的情况下,利用现今的方法可以计算动态储量,并能够准确拟合生产历史,但会使动态储量计算结果存在很大的不确定性。因此关井测压资料对动态储量的准确计算十分重要。对于异常高压气藏,储层岩石有效压缩系数对动态储量计算结果的影响不可忽视,岩石有效压缩系数取值越小,动态储量计算结果越大,在开发早期计算动态储量时应该确定可靠的岩石有效压缩系数值。

The traditional method which is based on the material balance formula uses the shut-in pressure measurement data to calculate the dynamic reserves.However,the modern method,with the plate fitting method of gas well production performance curve characteristics as the primary method,uses the flowing pressure to calculate gas well dynamic reserves.Then based on the analytical comparison of these two methods and the cases of dynamic reserves calculation in the developed gas fields at home and abroad,the study of influences of shut-in pressure data and rock effective compressibility on the dynamic reserves calculation is conducted.The results show that without shut-in pressure measurement data,the modern method can still be used to calculate dynamic reserves and can accurately fit the production history,but there will be great uncertainty about the results.Therefore,the shut-in pressure measurement data is of great importance to the dynamic reserves calculation;while for the abnormally high pressured gas reservoirs,the influence of reservoir rock's effective compressibility on the dynamic reserves calculation can not be neglected,the smaller the rock compressibility value is,the bigger the dynamic reserves calculation result is,hence,the reliable rock effective compressibility should be determined when calculating the dynamic reserves at the early development stage.