In situ Measurements of Contact Angle Distribution From Multiphase Micro-CT Images Presenter: Ahmed Ahed Al-Ratrout Supervisors: Prof. Martin J. Blunt Dr. Branko Bijeljic

Outline  Introduction  Theory and workflow  Case 1: Cylindrical droplet_flat_h50 (θ = 90 o )  Case 2: Spherical droplet_flat_h50 (θ = 90 o )  Case 3: Spherical droplet_tilted surface  Case 4: Spherical droplet_transformed image  Oil/brine system results  Summary and Future work Slide 2

Introduction Slide 3 Water-wetOil-wet Measure θ distribution at pore-scale level for a whole rock sample automatically 3-phase contact line D Using of micro-CT imaging widely in petroleum engineering: A.Defining porosity in carbonates (Sok R.M.,2010) B.Fluid displacements visualization (Pak et al., 2013) C.Dynamic contact angle measurements (Hashmati M., 2014) D.In-situ contact angle measurements of scCO2 (Andrew M., 2014).

Contact angle Slide 4 Young-Laplace equation: - Two equilibrium phases in a cylindrical tube: Smoothing connected surfaces and re- uniformalizing the fluid-fluid curvature (constant) R r θ

Principle Slide 5 Fluid-fluid Interface Fluid-Fluid θ solid n| fluid-fluid - n solid Contact Line θ

Principle Slide 6 Fluid-fluid θ Solid Contact Line θ Fluid-fluid Interface n| fluid-fluid -n solid

Surface extraction Input data: 3-phase binary raw image Theory and workflow Surface smoothing Measure contact angle distribution Oil-rock surface brine-rock surface Oil-brine surface Validation: volume preservation and curvature uniformization

Case-1: cylindrical droplet_flat_h50 (θ = 90 o ) Slide 8 Guassian smoothing only Guassian + Curvature smoothing

Case-2: spherical droplet_flat_h50 (θ = 90 o ) Slide 9 Guassian smoothing only Guassian + Curvature smoothing

Slide 10 A B θ θ Case-3: spherical droplet_tilted surface

Slide 11 Impact of voxels local arrangement on the measurement! Case-3: spherical droplet_tilted surface

Slide 12 Case-3: spherical droplet_tilted surface Guassian smoothing only Guassian + Curvature smoothing

Slide 13 Case-3: spherical droplet_tilted surface

Slide 14 Case-3: spherical droplet_tilted surface BA C

Case-4: Spherical droplet_transformed image Slide 15 Image transformed

Slide 16 Guassian + Curvature smoothing Avg_Contact Angle Case-4: Spherical droplet_transformed image

Results of Oil/Brine system Slide 17 A.Subvolume location of the segmented data at resolution of 6.4 microns/voxels. B.A 3D rendering of the higher resolution image (2 micrometer/voxel) showing a trapped oil ganglion (red) by brine (blue) in a single pore. (Kamaljit 2015)

Results of Oil/Brine system Slide 18

Results of Oil/Brine system Slide 19 Count 2141 Mean Mean Deviation13.996

Summary and future work Slide 20  We have presented a new method for measuring the contact angle distribution numerically from multiple immiscible fluid images.  Further analysis and sensitivity on artificial images with different resolutions.  Further improvements are under development to reduce uncertainty and errors in the measurements.

Summary and future work Slide 21  In future work, these angles will be input directly – on a pore-by-pore basis – into a pore-network model based on the dry scan of the rock. We will then make predictions of relative permeability and capillary pressure and show how a direct determination of contact angle (as opposed to some guessed random distribution, as done at present) affects the results.  ADCO has sent 9 rock samples (SCAL data of 2 samples) + 100L of crude oil of a giant carbonate reservoir in Abu Dhabi, to be part of this study.

Acknowledgements / Thank You / Questions Acknowledgement to ADNOC and ADCO management for the sponsorship of this PhD program. Acknowledgment to the supervisors Prof. Martin and Dr. Branko Acknowledgment to Dr. Ali Raeini for his valuable effort and support, Dr. Kamaljit Singh for his valuable advices and guidance Your attendance and valuable questions Slide 22