VSD模型在评估煤层气储量中的应用

煤层气是非常规天然气的一种,是国内天然气产量的重要组成部分.经过多年勘探开发,沁水盆地南部和鄂尔多斯盆地东部已经形成多了商业开发区块,获得了大量精确的储量数据;但中国煤层气分布广泛,勘探程度不一,储量认知程度严重不均衡.通过勘探程度较高的储量数据来预测所有区块的储量.为了正确预测和评价国内煤层气资源量.评价模型中选用VSD(variable shape distribution)模型,与常规分形分布模型相比,比如对数正态分布和帕累托分布,具有精度高,拟合灵活准确的特点.在成熟度高的气田储量基础上,拟合出VS模型所需的参数,然后利用这套参数预测评价出国内81个煤层气区块的资源量,为煤层气的勘探部署和经济分析提供参考数据.

Evaluate Proved Reserves of CBM in China by New Model

The coalbed methane (CMB) makes up a big proportion of unconventional natural gas in China. CBM is promising after exploration and development in the last decade. China has accumulated very rich data of reserves, especially in Qinshui Basin and Ordos Basin where CBM fields are in commercial developing stage. But these data is far from sufficient to evaluate Chinese CBM reserves. A lot of potential provinces have not obtained proved reserves. Although the CBM distributes widely but the degree of exploration is strongly unequal. According to previous research, there are 11 provinces of CMB whose reserves have proved. Other provinces, in Junger basin, Tuha basin and so on, have not shown their accurate reserves. This study focuses on predicting total proved reserves of CMB in China. To predict proved reserves, the variable shape distribution (VSD) model is chosen in this study, which is more accurate and flexible than Pareto distribution and Lognormal distribution. Furthermore, two parameters are introduced in this model to make it match real data more properly. This VSD model is utilized to predict proved reserves of 81 provinces. The result shows that there is huge potential for China to develop CMB industry. This can provide basic data for exploration development and economic analysis of CMB. But risks can not be ignored, including geology and policy. The details of risks are analyzed at the end of this study.