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Reservoir Modelling: A Practical Guide


Steve Cannon

Principal Consultant
Steve Cannon Geoscience






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To all the Cannons, Nichols, Whitleys, Reeves and Watsons who\break have supported my geological studies, especially on the beach at Porthmadog and many other outcrops around the world!


This book has matured over 40 years of practical oilfield experience in mud logging and well site operations, from core analysis to sedimentology and reservoir modelling to field development: I have been fortunate to have had the opportunity to be employed in a variety of different roles for a wide range of companies and organizations. All of this has culminated in the opportunity to teach a successful course on integrated reservoir modelling, which forms the foundation of this book.

By profession, I am a geologist, by inclination a petrophysicist and I am a reservoir modeller by design. In reality, I promote the building of fit-for-purpose reservoir models to address specific uncertainties related to hydrocarbon distribution and geological heterogeneity that impacts fluid flow in the reservoir. A simple mantra for reservoir modelling, as in life, is ‘keep it simple’: we never have enough knowledge or data to rebuild the subsurface only to try and make a meaningful representation of the reservoir.

My background in reservoir evaluation gives me the experience to promote 3D modelling as a solution to most field development and production challenges as long as the question being asked is properly defined. Reservoir simulation projects are clearly designed to address specific issues, so should geological models, be it volumetric estimation, well planning or production optimization. This book is focused on the development of structurally complex, clastic, offshore fields rather than large onshore producing fields. This is largely because of the difference in well numbers and spacing; geostatistical software modelling products were developed specifically for these challenges. That the same tools have been expanded for use in giant onshore fields with a large well count has made 3D geo-modelling the tool of choice for reservoir characterization and dynamic simulation.

The person building a reservoir model can be part of a multidisciplinary team, the ideal situation in my view: or a geologist who knows how to use the software and is part of a linear workflow that starts with the geophysicist and ends with a reservoir engineer; in this case, each discipline often uses a different software product and there is minimal discussion at each stage of the process. Increasingly, the seismic interpreter can build the structural model as the first step and the geologist builds and populates the grid. Whichever situation you find yourself in, it is essential to take the rest of the stakeholders with you at each stage of the model.

The book does not promote one type of method over another or specify one commercial product above another; I am grateful to a number of organisations that have provided me with the tools of my trade, especially Schlumberger and Emerson-Roxar. My background as a consultant with Roxar Software Solutions from 2000 to 2008 defines my preference for object modelling of geological facies, rather than pixel-based methods, but in reality, the software tools available to the modeller allow a wealth of options. I would like to thank Aonghus O'Carrol, Dave Hardy, Neil Price, Doug Ross, Tina Szucs and all the people who have told me to ‘RTBM’ and play with the software. My thanks also to Steve Pickering and Loz Darmon from Schlumberger-NExT who encouraged me to develop the course and supported me during the delivery of the material to over 200 students worldwide and to Rimas Gaizutis who may recognize some of these ideas from working together in the past.

Finally, I am not an academic and this is not an academic treatise but a practical handbook. Many people will disagree with my philosophy when it comes to reservoir modelling, but when you are limited by: time, data or resources, pragmatism and compromise are the order of the day. A wise man once wrote, ‘all models are wrong, though some can be useful’ (Box, 1979).

Steve Cannon