煤层气储层数值模拟研究的应用

APLICATION OF COALBED METHANE RESERVOIR SIMULATION

储层数值模拟是确定煤层气开发方案和评价采收率的有效方法,其遵循常规油气藏数值模拟步骤,通常包括选择模型、资料输入、灵敏度试验、历史拟合和动态预测5个环节。煤层气属于非常规天然气,其储层数值模拟基于解吸—扩散—渗流的地质模型,在具体模拟过程中具有自身的特点。结合在新集煤层气试验区开展的储层数值模拟研究工作,重点阐述了模拟研究中的两个重要环节:模拟模型的建立(资料输入)和历史拟合。模拟模型的建立是进行储层数值模拟工作的基础,试验区模拟模型的具体内容包括:确定模拟区域及边界条件,剖分网格、确定流体的PVT性质参数、处理储层描述数据和处理动态数据等。历史拟合是运用已有生产井的动态资料校正模拟模型的逆过程。通过历史拟合,获得了更能够真实反映试验区储层特征的参数,分析了5煤层和6煤层附近的大段砂岩层对煤层气产量的贡献,提出了排采作业建议,并采用历史拟合的储层参数进行了动态预测。

Coalbed methane reservoir simulation is the method currently available to determine operating strategies and estimate ultimate field recovery. Reservoir simulation follows the steps in performing a conventional reservoir simulation study. These steps involve selecting simulator, establishing simulation model, performing sensitivity analyses, adjusting history matching parameters and forcasting production. Coalbed methane is an unconventional natural gas. Based on the geology model of desorption-diffusion-Darcy flow,coalbed methane reservoir simulation has its own characters. Systemic reservoir simulation has been performed in Xinji test area of coalbed methane. The establishment of simulation model and history matching have been emphasized in the article. Simulating coalbed methane reservoirs is based on the establishment of simulation model, in Xinji test area which consists of determining the area of simulation and boundary conditions,designing the simulation grid, handling fluid PVT data,reservoir description data and recurrent data and so on. History matching is the process of calibrating a simulation model to past performance of wells. By history matching a reservoir model that describes the real reservoir has been created in Xinji test area. Whether the thick sandstone adjacent to No. 5 and 6 coal seam contributes to gas production is analysed. Then suggests aimed to the behavior of the production wells has been put forward. At last the history match data has been used to predict production rates of wells.