澳大利亚S区块基于复合参数模型的煤层含气量预测

Coalbed methane gas content prediction by compound parameter model in S block of Australia

含气量预测的准确性对于煤层气开发至关重要。测井曲线作为含气量表征的最常用资料,不同测井资料对于含气量变化的响应灵敏程度不一样,单一的测井曲线预测含气量稳定性差。为了研究煤层含气量的精确预测方法,以澳大利亚S区块的煤层气为研究对象,以实验室分析数据、测井资料为基础,通过测井资料响应特征分析,实现测井资料的扩径校正以及含气量数据深度归位处理。在此基础上,根据含气量与测井资料相关性分析结果,选择煤层埋藏深度、声波时差、自然伽马和长源距密度等相关性好的测井数据作为含气量预测的基础参数。以基础参数对含气量的敏感性分析结果为依据,构建含气量预测的复合参数,建立基于测井资料的含气量复合参数预测模型。通过软件中编写含气量计算的外挂模块实现煤层气井含气量批量计算。复合参数预测模型在实际应用中,可以克服传统煤层含气量计算准确率低、稳定性差的缺点,同时可以实现批量化计算,极大地加快含气量计算进度,能够为S区块的后续煤层气开发奠定地质基础。

Gas content is the most important research content for coalbed methane（CBM） development. Accuracy characterization is very important for CBM. Logging characterization of gas content is the most commonly used method, while different logs have different sensitivity to the change of gas content, and single logging curve predicting coalbed methane content has the disadvantages of poor stability and low accuracy. In order to study the accurate prediction method of CBM, CBM reservoirs in S Block of Australia is taken as study object. Based on the laboratory analysis data and logging data, the logging data response analysis was carried out to realize logging data expansion correction and depth shift. Logging data such as buried coal depth, AC, GR and LSD were selected as the basic parameters for gas content prediction on the basis of correlation analysis between gas content and logging data. After the sensitivity analysis between gas content and logging data, compound parameters of gas content prediction were constructed, and finally the compound parameter prediction model for gas content prediction was established. Batch calculation of CBM was achieved by plug-in module of logging interpretation software. In the practical application, the prediction model can overcome the shortcomings of the low accuracy and poor stability of the traditional coal seam gas content calculation. At the same time, it can realize the batch calculation and greatly speed up the calculation of gas content. The prediction of gas content by compound parameters can also provide a solid geological foundation for the CBM subsequent development of S block.