The Executive Editors of SPE Reservoir Evaluation & Engineering alternate writing the Executive Summary. This issue's summary is written by Birol Dindoruk.
This is my last column as co-Executive Editor of SPEREE. I would like to take this opportunity to thank the SPE staff, especially Stacie Hughes, Jennifer Wegman, and Carole Young, for doing an excellent job in helping all of us collectively deliver a quality journal. They were instrumental in helping me assign papers and track the progress of reviews, particularly during my never-ending long distance business trips with unpredictable Internet connections. I also thank all the Technical Editors and Review Chairs for their services and their contributions to the reservoir engineering literature. Despite their busy work schedules, they made the most of their personal time to review papers as quickly as possible. Finally, I would like to welcome Behrooz Fattahi as my successor; I am sure many of you know Behrooz from his previous role as a Review Chair, and I am confident that he will do an excellent job as an Executive Editor.
There are always numerous questions about the review process and why a small fraction of the reviews take longer than others. Therefore, I would like to highlight some observations I’ve made over the past 2 years:
It should be noted, however, that peer-review time is improving across all SPE technical journals. In 2004, it took an average of 8.5 months to complete a review; for 2005, that number dropped to 7.3 months. We continually strive to meet the Editorial Review Committee’s benchmark of reviewing all papers within 18 months of submission. Please let us know if you are interested in reviewing papers and making this process even more efficient.
In this issue, we have many good papers on a wide spectrum of reservoir engineering subjects (from upscaling fracture networks for simulation of horizontal wells to identifying reservoir fluids by wavelet transform of well logs). As the number of different areas that we work on as reservoir engineers varies over time, one of the themes that remains constant is being able to assist in decision making, from where and when to drill wells to what method to use to exploit hydrocarbons more efficiently. Because scoping or feasibility studies on improved/enhanced oil recovery projects are on the rise, one of our biggest challenges is residual oil saturation, or SOR; the evidence for that is overwhelming, give or take the two thirds of oil left in the ground. In fact, during a conversation with one of my colleagues, the case was even more obvious. He mentioned that when he joined the oil industry some 20 years ago, he had heard that most of the oil in reservoirs was left behind and thought that it would be a great challenge to be able to recover some of that oil. Then, he added that some 20 years later, the overall amount of oil left behind has not changed much. The reason that I wanted to highlight this is that our battle against SOR is not over yet. In the same context, as you may expect, the conversation went directly toward issues like the price of oil, and one of my colleagues and I came up with a “scientific explanation”: “hydrocarbon molecules have no way of knowing what the price is.” I think it is very true that due to the cyclic nature of our industry, we sometimes forget what those molecules really know or do not know. I see SOR as being the grand challenge of reservoir engineering. Of course, the grand challenge has the grand constraints: mobilization of the hydrocarbons using a minimum number of control points (wells). The analogy that I draw is the following: we do not have power plants on every street; however, we can distribute power efficiently across long distances. You may, of course, argue that it is not the same problem, but the issue is to be able to do something similar using the wells, distributing what we want to deliver efficiently into the reservoir across long distances. However, the transmission/distribution problem with respect to classical power distribution is somewhat different; what we want to do has higher dimensionality and complexity.
Another difficulty in what we do is the scarcity or uncertainty of data with respect to the areal and vertical heterogeneities that we encounter. Basically, we do not fully know the domain of interest, especially its flow properties. Therefore, such unknown or known heterogeneities can complicate our job of reducing SOR tremendously. As one of my professors once noted, “I can make any easy differential equation very difficult by making the initial or boundary conditions difficult.” Because the geology and the fluid properties (PVT) are the ultimate initial condition for us, the same complication applies in understanding the flow behavior and ultimately being able to design a process to reduce SOR.
As we are depleting “easy oil,” our fundamental challenges are still there, and as reservoir engineers, our talents are more in demand than ever. One of the most satisfying aspects of reservoir engineering (and petroleum engineering as a whole) is that it is a combination of both science and art. The “art” part that is somewhat analogous to experience is so important that it is an integral part of decision-making processes. While our classical challenges are here to stay for the foreseeable future, this should not discourage us from finding better, more innovative ways to exploit energy resources. I would like to close with something that I truly believe: “What is impossible today will be easy and possible tomorrow,” and “If your job can be done by a machine, then it soon will be.”