3D Images of residual oil in an Ottawa sand Congjiao Xie, Saif Ai-Sayari and Martin Blunt Earth Science and Engineering, Imperial College London

Outline Aims Overview Experimental set-up –The Hassler cell for Benchmark experiments –Apparatus for tiny samples –Micro-CT Results –2D image –3D first results Future Work Acknowledgements

Aims To set up a new apparatus to image fluid distribution at the pore scale using micro- CT To gain a 3D image of the flow behavior at pore scale when brine, oil and gels are used To find the distribution of residual oil after the flow of water and cross-linked polyacrylamide

Overview Reservoir engineering methods Numerical Simulation Micro-scale tests

Procedure Micro-CT imaging Tiny Core Plug Pores throats coordination numbers Fluid characterization Actual network Lattice Boltzmann Geometry Network geometry Element permeabilities Fluids parameters Core prediction Permeabilities Fluid parameters Fluids injection

Experimental set-up Hassler cell

Experimental set-up Apparatus for tiny samples PVC-U ( Polyvinyl Chloride ) max operating temperature is 60 ℃ 37.8mm 25.4mm 6.5 mm

Experimental set-up Apparatus for tiny sample Injection sequence: 30 PV of oil 70 PV of brine 10 PV of Gel (HPAM) (a low molecular weight and low hydrolysis polyacrylamide cross-linked with chromium) 20 PV of oil 3 PV of brine

Experimental set-up Properties of fluids Fluids ℃ (gm/cm 3 ) ℃ (mPa.s) Brine (5% Nacl + 1% Kcl) Oil ( Multipar H) HPAM Gel (Tetramethoxysilane)

Experimental set-up Apparatus for tiny sample A range of rates from 0.5 to 50 cc/min

Experimental set-up Micro-CT scanner

Results Porosity Permeability Relative permeability Ø=26.4%,K=200.8md Ø=23.4%,K=133md Sw=44% Sw=50% Sor=27% Sor=30%

Results No.DatePorosityPermeability %2.12D %2.41D %2.28D No.DatePorosityPermeability %2.01D %2.25D %2.13D D=37.8 mm D=6.6 mm

A subregion in Sw (b) The same region in Sor (c) pore/rock and brine/oil segmentation results for this region From M.Prodanovic et al.2006 Results 2D image

Results 3D first results Micro-CT data Petrel Software Modelling 3D image

Future Works Injecting Gel to simulate Polymer Drive Mechanism Injecting nitrogen and water to study three-phase flow Comparison of Micro-CT results with Benchmark experimental data on sand packs and sandstones

Residual oil distribution after cross-linked polymer flooding at different steps in Xiaermen oil field, China a c b grain

Residual oil distribution for different sandstone models From Xiaermen oil field, China Crosslinked polymer Residual oil after polymer flooding crosslinked polymer extended residual oil skeleton

Future Works Distribution of residual oil saturation as a function of wettability and saturation history

Acknowledgements I would like to express my sincere thanks to my supervisor Prof.Martin Blunt for his guidance and support throughout this work. I’m also grateful to Dr. Mariela for her initial discussions. I’d like to thank the administration of Petrophysics lab engineers for their helps. I’m also grateful to the staff for their friendly environment.

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