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TU Clausthal
24.06.2021 | Research, Publications

Research report published: Numerical and model-physical investigations of innovative frac technologies with alternative frac fluid for tight gas formations also with re-frac options

The DGMK Project 814 'Numerical and Model-Physical Investigations on Innovative Frac-Technologies with Alternative Frac-Fluids for Tight Gas Formations and Re-Fracturing Options' was completed. The following is a brief description of the project.

Hydraulic fracking treatment is the first choice for increasing the productivity of tight gas reservoirs. However, conventional frac fluids cause delayed fracture closure and inadequate cleaning, resulting in inefficient fracturing operations. The solution is to replace the existing water-based fluids with alternative fluids to overcome the technical challenges in tight and ultra-tight gas reservoirs for better proppant placement and fracture conductivity. Moreover, the environmental issues such as excessive water consumption and wastewater disposal could be minimized. In this context, light alkanes are proposed as alternative frac fluids. In order to model the temperature, pressure and composition dependent behavior of light alkanes for hydraulic fracturing, a multiphase thermo-hydromechanically coupled multicomponent numerical simulator was developed and verified.

Application of the developed model to the case study of a tight gas reservoir in Germany and sensitivity analysis showed that the alternative fluid leads to fast fracture closure and fast flowback, resulting in better well-fracture connectivity and minimization of phase trapping while limiting water consumption. A new production optimization model was also implemented using proppants of different shapes. The use of rod-shaped proppants can further strengthen well productivity compared to spherical proppants due to the higher porosity and permeability of cylindrical proppant packing.

Research Center

Institute of Subsurface Energy Systems, TU Clausthal

DGMK-Research Report 814 has been published in English and can be ordered now. directly from the DGMK .