基于实验测量和文献调研建立了包含700多个样本的凝析气藏数据集,对常用的计算露点压力的经验关系式和状态方程进行了评估,并新建了一个经验关系式,对各种关系式及Peng-Robinson状态方程进行了对比评估和参数敏感性分析。研究表明,目前常用的凝析气判别标准不够准确;Peng-Robinson状态方程不具有唯一解,受C7+组分的表征关系式和分割方案等多种因素的影响;应用于建立的数据集时,Nemeth-Kennedy关系式准确度最高,其次为Elsharkawy关系式和Godwin关系式,Shokir关系式由于无法用于不含C7+组分的样本,准确度最低;新建关系式的平均绝对误差、均方根误差和决定系数分别为7.6%,588和0.87,在统计学意义上优于前人4种关系式。通过与实验数据和Peng-Robinson状态方程模拟结果进行对比验证了新建关系式的准确性和有效性。图13表16参36
ALAROUJ Mutlaq
,
ALOMAIR Osamah
,
ELSHARKAWY Adel
. 凝析气藏露点压力计算方法[J]. 石油勘探与开发, 2020
, 47(5)
: 1016
-1026
.
DOI: 10.11698/PED.2020.05.16
A large data bank of more than 700 gas-condensate samples collected from literatures and experiments was established. On this basis, empirical correlations equations of state commonly used to calculate dew-point pressure (DDP) were evaluated, a new model for estimating DPP was proposed, all the empirical correlations and Peng-Robinson state equation were compared, and sensitivity of parameters was analyzed. The current standard used to identify gas condensate isn't accurate enough. The Peng-Robinson state equation has no unique solution and is affected by multiple factors such as the characterization relation of C7+ components and the splitting scheme. The Nemeth-Kennedy correlation has the highest accuracy when applied to the data bank established in this study, followed by Elsharkawy correlation and Godwin correlation, Shokir correlation can't be used to samples without C7+ components and thus is the lowest in accuracy. The newly proposed model has an average absolute error, root mean square error and coefficient of determination of 7.5%, 588, and 0.87, respectively, and is better than the above four correlations statistically. The proposed model was proved accurate and valid by comparing its results with experimental data and the results of simulation with Peng-Robinson state equation.
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