The development and application of chemical-in-gas stable dispersions is described for use as a novel approach to IOR/EOR in tight formations. The development of this unique process as a stimulation and recovery method is described through workflow processes and field examples.
The injection of chemical-in-gas stable dispersions was first proposed, outlined, and described in two key publications by Restrepo et al. in 2012 [Restrepo et al, 2012]. Since then, an extensive suite of successful enhanced-recovery well trials and operations have been executed, across the complex compositional reservoirs of the Andes foothills. Detailed information related to droplet transport, retention, and adsorption phenomena, occurring during placement, soaking and back production; has been obtained. These behaviors have then been examined using mathematical models and numerical approximations; as well as being calibrated to core results.
Widespread and successful IOR/EOR field applications have included condensate bank removal, gas injection conformance, asphaltenes dissolution/inhibition and induced water blockage removal. Typical oil and gas production increases, achieved after the injection of the chemical-in-gas dispersions for IOR, have ranged between 15% and 35% depending upon the pre-existing well/reservoir conditions, available data for planning and the detail of the treatment characteristics itself. Also, for IOR, long term production sustainability of between 3 to 15 months has been achieved depending upon the chemical adsorption and desorption effectiveness and damage restoration rates. This period of sustainability is 2 to 3 times that achieved by more conventional methods. Most recent enhancements to the technique include the chemical screening and core-flood testing of new and advanced IOR/EOR chemical solutions. These include the application of dispersible RPMs as well as encapsulated acids for clay dissolution; this has been complemented by the development of bespoke simulation tools to simulate the fundamental physics of the process.
This work presents a detailed overview of the observations, learnings and remaining challenges related to the injection of chemical-in-gas stable dispersions. Reporting on several field applications that are then also history matched with the latest modelling approach. Finally, a discussion pertaining to the most recent chemical-in-gas dispersion systems and deployment prototypes will be presented as the foundation for a suite of new and novel IOR/EOR techniques available to the industry.