页岩及其矿物和有机质成分对多组分气体的吸附与解吸附机理研究

The calculation of gas in place and fluids rate forecast for shale gas which are important unresolved problems base on the flow mechanism in which involves three points of difficulty, the adsorption and desorption, gas flow in nanoscale pores, mass transfer process of multi-mechanism in multiscale porous media which from matrix to natural crack and to artificial fracture network. The latter two points are difficult to study on the condition of research at present, only the gas adsorption and desorption which is starting and basis of mass transfer of gas in the shale can research by adsorption isotherm experiment, but it received less attention while drilling and reservoir reconstruction and evaluation are research focus generally. So the project focus on mechanism of adsorption and desorption of multicomponent gas to shale and its mineral and organic matter composition, analyse by adsorption isotherm and desorption experiments and model it ,provide a theoretical support for efficient development of shale gas .

页岩气的储量计算和产能预测是其开发中亟待解决的重要问题，研究两者都要以渗流机理为基础，其所包括的纳米级孔隙中的气体渗流和气体从基质到自然裂缝再到人工裂缝网络的含解吸与扩散耦合渗流的研究条件还相对不成熟，唯页岩气的吸附与解吸附可通过宏观实验来实现，目前国内页岩气研究热点也主要在钻井、储层评价和改造等与工艺密切相关的领域，对页岩气渗流的起点或基础- - 吸附和解吸附关注相对较少，所以本项目拟从最基础做起，集中针对页岩及其储层各种矿物和有机质成分对多组分气体的吸附与解吸附机理进行研究，由单一矿物和有机质样品到混合样品再到真实页岩岩样，由单一的甲烷气到烃类混合气再到烃类和非烃类混合气逐步推进，进行等温吸附和解吸附实验，并分析和建立相对应的吸附与解吸附数学模型，为页岩气高效开发提供理论支撑。

近年来得益于钻井和压裂技术的进步，来自页岩气藏的天然气产量正稳步提高。页岩气藏与常规气藏的区别在于，除游离气外，页岩中的气体还吸附在基质孔隙中。页岩气的吸附、解吸、扩散乃至渗流机理及影响因素是页岩气资源评价和产能预测研究的基础。本课题进行了页岩及其有机质和粘土矿物的等温吸附、孔隙体积分布测试和气体解吸扩散实验研究，得到了页岩组成、孔隙性质和温压条件以及样品含水率和粒径对页岩中气体吸附、解吸和扩散过程的影响规律。此外，还进行了页岩扩散系数和视渗透率的理论计算，和考虑了页岩对气体吸附的储层敏感性和伤害评价研究，以分析气体在页岩中解吸、扩散和渗流耦合过程机理。