In situ Measurements of Contact Angle and implications fro pore-scale displacement Presenter: Ahmed Ahed Al-Ratrout Supervisors: Prof. Martin J. Blunt Dr. Branko Bijeljic

Outline Introduction Background and Literature review Objectives Work Flow Contact line and surface extraction Smoothing the extracted surfaces Research Milestones Research Gant chart Slide 2 2

Outline Introduction Background and Literature review Objectives Work Flow Contact line and surface extraction Smoothing the extracted surfaces Research Milestones Research Gant chart Slide 3 3

How to measure wettability? How to map wettability? Introduction Water-wet Oil-wet Contact line How to measure wettability? How to map wettability? Although, wettability of particular RRT may be quantified in the laboratory through the use of indices, such as Amot-Index and USBM, or by using relative permeability characteristics. It is, fundamentally, well known that wettability is described in terms of contact angle measurements more accurately. Conventionally, laboratory contact angle measurements are applied using flat singular mineral surfaces, typically silica and/or quartz and calcite to symbolize sandstones and carbonates, respectively. The fact that reservoir rocks contains other minerals and rough surfaces, which causes changes in wettability preferences and contact angle hysteresis, respectively. Therefore, these measurements may not be accurate to represent the operative contact angle and actual wettability within reservoir rocks. Measure θ at each invaded pore at every voxel point on contact line? Slide 4 4

Outline Introduction Background and Literature review Objectives Work Flow Contact line and surface extraction Smoothing the extracted surfaces Research Milestones Research Gant chart Slide 5 5

Background and Literature review In the past 3 decades, different definitions of wettability and contact angle measurements have been proposed and applied in the literature: Brown & Fatt Amot Morrow Donaldson (USBM) (1956) (1975) (1959) (1969, 1980 & 1981) Adamson Neumann / Good (1982) (1979) Most of these approaches were applied on singular mineral flat surfaces, or had big uncertainties! Slide 6 6

Outline Introduction Background and Literature review Objectives Work Flow Contact line and surface extraction Smoothing the extracted surfaces Research Milestones Research Gant chart Slide 7 7

Objectives Develop a method to measure contact angle (θ) in Oil/Brine system. As more accuracy, this computational process outputs a list of θ values (range), that corresponds to each invaded pore-elements (pores and throats). The list of computed angles at each invaded pore-element, rather than single value for the whole 3D-image, are implemented as an input to perform pore-network 2-phase flow simulation. For the studied Kr experiments (which can represent accuracy level and extrapolation interval reliability). with USS Kr saturation working span conditions USS Kr profiles will be generated to judge if OPCOs should go for USS or SS for different rock types & reservoir fluids.

Outline Introduction Background and Literature review Objectives Work Flow Contact line and surface extraction Smoothing the extracted surfaces Research Milestones Research Gant chart Slide 9 9

Workflow Rock Oil Water Rock Contact Line Interface Oil n|w θ θ Water Contact line -Solid Rock Slide 10

Outline Introduction Background and Literature review Objectives Work Flow Contact line and surface extraction Smoothing the extracted surfaces Research Milestones Research Gant chart Slide 11 11

Contact line and surface extraction In order to estimate nw and n|w, we need to extracting from the segmented image the following: Contact lines Oil/brine interface Solid surface Aliasing issue! Due to roughness of the rock surface and voxel representation of the 3D image, aliasing artifacts ((jagginess and terracing) can be exhibited during the extraction of the isosurfaces and contact lines (Lempitsky, 2010). A). The binary volume and its zero-isoline. B) zer-isosurface of binary volume (Lempitsky, 2010). Slide 12

Outline Introduction Background and Literature review Objectives Work Flow Contact line and surface extraction Smoothing the extracted surfaces Research Milestones Research Gant chart Slide 13 13

Smoothing the extracted surfaces This aliasing problem distracts tracing the required two vectors along the solid wall of the rock and the oil-brine interface, which, may lead to incorrect angle measurements (Andrew et al., 2014). Gaussian pre-filtering Minimal area seperating surfaces (Gibson, 1998) Higher order smoothing method (Lempitsky, 2010) In this study, these methods are optimized in details to analyze the impact of extracting smooth surfaces on the roughness of rock surfaces and oil-brine interfaces Slide 14

Outline Introduction Background and Literature review Objectives Work Flow Contact line and surface extraction Smoothing the extracted surfaces Research Milestones Research Gant chart Slide 15 15

Research Millestones Literature review Data Gathering Phase I Phase II Data review and classification Phase I Code development using C++ Phase II Apply results in 2-phase simulation Sensitivity analysis Results Validation Final Report Slide 16

Research Gant chart Slide 17

References Adamson, A.W.., 1982. Physical Chemistry of Surfaces. fourth edition, pp.332-68. Amott, E., 1959. Observations Relating to the Wettability of Porous Rock. Trans., 216, pp.156-62. Anderson, W.G.(.I.)., 1986. Wettability Literature Survery - Part 1: Roc/Oil/Brine Interactions and the Effects of Core Handling on Wettability. Jornal of Petroleum Technology, 38(10), pp.1125 - 1144. DOI: http://dx.doi.org/10.2118/13932-PA. Anderson, W.G.(.I.)., 1986. Wettability Literature Survey - Part 2: Wettability Measurement. Journal of Petroleum Technologies, 38(11), pp.1246-62. DOI: http://dx.doi.org/10.2118/13933-PA. Andrew, M., Bijeljic, B. & Blunt, M.J., 2014. Pore-scale contact angle measurements at reservoir conditions using X-Ray microtomography. Advances in Water Resources, 68(2014), pp.24-31. Brown, R.J.S. & Fatt, I., 1956. Measurements of Fractional Wettability of Oil Field Rocks by Nuclear Magnetic Relaxation Method. JPT, 11, p.262. Donaldson, E.C. & al., e., 1980. Equipment and Procedures for Fluid Flow and Wettability Tests of Geological Materials. Bartlesville Energy Technology Center. report DOE/BETC/IC 79/5, U.S. DOE. Donaldson, E.C., Thomas, R.D. & Lorenz, P.B., 1969. Wettabili- ty Determination and Its Effect on Recovery Efficiency. SPE, pp.13-20. Fatt, I., 1956. The network model of porous media. Petroleum Transactions, 207, pp.144-81. Good, R.I., 1979. Contact Angles and the Surface Free Energy of Solids. Surface and Colloid Science, 11, pp.1-29. Morrow, N.R.., 1975. Effects of surface-roughness on contact angle with special reference to petroleum recovery. J. Can. Pet. Technol., 14(4), pp.42-53. Neumann, A.W.a.G.R.J., 1979. Techniques of Measuring Contact Angles. Surface and Colloid Science, 11, pp.31-91. Pak, T. et al., 2013. Pore-Scale Visualisation of Two-Phase Fluid Displacement Processes in a Carbonate Rock using X-ray micro-Tomography Technique. In RCSC. Abu Dhabi, 2013. SPE. Valvatne, P.H. & Blunt, M.J., 2004. Predictive pore-scale modeling of two-phase flow in mixed wet media. Water Resources Research, 40(2004), pp.1-21.

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, Dr. Kamaljit Singh and Matthew Andrew for the valuable advices and guidances Your attendance and valuable questions Slide 19