Aigerim Raimbay

MSc 2015

Co-advisor: Dr. E. Kuru

Research topic: “Effects of Proppant Characteristics on Gas-Water Flow in Rough Fractures” 

Thesis

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Proppant embedment is one of the critical aspects in fracking design. The embedment of proppants depends on aperture distribution, contact area, and closures, which are functions of the surface roughness. Therefore, the optimum distribution of propping agents that prevents “healing” and, thus, offers the greatest permeability is under the scope of the most recent studies. However, there are very limited studies on the effect of different rock types with different roughness characteristics on permeability in the presence of proppant agent.

The objective of this research is to examine fluid-gas flow and proppant transport in rough fractures of different rock samples (e.g. granite, marble, and limestone), and their effect on permeability of different fractal dimension fractures. Two main aspects are under the study in this research:

1. Selection the proppant type and concentration, which would provide the highest permeability in different reservoirs.

2. Selection the composition of fluid for proper transportation and placing of propping agents.

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Since the introduction of hydraulic fracturing technique, industry has been attempted to enhance production of hydrocarbon from tight reservoirs by selecting optimum design of hydraulic fracturing treatment. One of the essential parameters in hydraulic fracturing design is the proper selection and injection of proppants. They not only provide fracture permeability but also prevent “healing” of fractures. Hence, the quantification of proppant transport characteristics is highly critical in a sustainable production from hydraulically fractured wells.

 

Previous studies in this regard were limited to smooth (parallel) fracture surfaces to a great extent ignoring the effect of roughness of fractures, which may have significant impact in controlling the permeability of hydraulic fractures in the presences of proppants. In this thesis, effect of surface roughness to fluid flow and transportation/distribution of propping agents were investigated through experimental work. Water and polymer solutions representing typical rheological properties of hydraulic fracturing fluids were injected through transparent models of the fractures of different origin rocks (granite, marble, and limestone) with and without propping agents. The permeability changes due to proppant distribution caused by the roughness of fracture surfaces were quantified and correlated to different fractal characteristics of surface roughness. Qualitative and quantitative analyses were supported by visualization of experiments.

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Publications:

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1. Raimbay, A., Babadagli, T., Kuru, E. and Develi, K.: “Quantitative and Visual Analysis of Proppant Transport in Rough Fractures,” J. of Natural Gas Sci. and Eng., vol. 33, 1291-1307, 2016.

2. Raimbay, A., Babadagli, T., Kuru, E. and Develi, K.: “Fractal Analysis of Single-Phase Water and Polymer Solution Flow at High Rates in Open and Horizontally Displaced Rough Fractures,” Int. J. of Rock Mech. & Min. Sci., vol. 92, 54-71, 2017.

3. Raimbay, A., Babadagli, T., Kuru, E. and Develi, K.: “Effect of Fracture Surface Roughness, Shear Displacement, Fluid Type and Proppant on the Permeability of a Single Fracture: A Visual and Quantitative Analysis,” accepted for publication in SPE Res. Eval. and Eng., 2016.

4. Raimbay, A., Babadagli, T., Kuru, E. and Develi, K.: “Effect of Fracture Surface Roughness and Shear Displacement on Permeability and Proppant Transportation in a Single Fracture,” SPE 171577, 2014 SPE Unconventional Res. Conf., Calgary, AB, Canada, 30 Sept.-2 Oct.

5. Raimbay, A., Babadagli, T., Kuru, E. and Develi, K.: “Quantitative and Visual Analysis of Proppant Transport in Rough Fractures and Aperture Stability,” SPE 173385, 2015 SPE Hydraulic Fracturing Technology Conf., The Woodlands, TX, USA, 3-5 Feb.

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