利用高温热处理提高致密储层渗透性

Advantages in Formation Heat Treatment to Enhance Permeability in Tight Reservoir

储层高温热处理是在常规增产改造效果不佳及致密油气资源亟待大规模开发的背景下形成的以岩石渗透性为对象、温度为核心的增产改造技术。梳理了高温热处理的室内实验评价方法。综合分析指出,高温下致密岩石所产生的一系列物理—化学变化,其实质是沿着一条孔隙水蒸发、矿物结构改变、裂缝网络形成的多尺度路径进行的,热应力作用下的微裂缝萌生、扩展及连通形成网络是强化其渗透性的主要机理。评述了高温热处理技术的现场成功案例。从致密储层多尺度效应及生产机理的角度,突出了高温热处理的优势,主要体现在解除水相圈闭损害、降低破裂压力、形成裂缝网络及增强气体在基块孔喉中的解吸和扩散能力,提出了集成高温热处理与压裂酸化以打造致密储层全方位、多尺度的增产改造措施。

As the effectiveness of conventional stimulation treatment is under-expected for tight reservoir and unconventional resources are urged to exploit,based on thermal properties of rock,formation heat treatment（FHT）,is developed as an innovative well stimulation technique,which is focused on the permeability of rock.Experimental evaluation methods of FHT are shown in this paper.Comprehensive analysis indicates that the essence of the physical-chemical changes for tight rock under high temperature is a set of multi-scale processes involving evaporation of water in pore,change of mineral structure and generation of fracture network.Under the action of thermal stress,the main mechanism of enhancing permeability is the fracture network developed from micro-fracture and fracture propagation.Successful field cases of FHT are presented.On the basis of multi-scale effect in tight reservoir and its production mechanism,the advantages of FHT are reflected in preventing water phase trapping,decreasing fracture pressure,forming fracture network,enhancing-desorption and diffusion of gas in pore.In view of multi-scale mass-transfer theory,a new well stimulation technique,integrated the superiority of FHT,fracturing and acidizing is expected.