Petroleum engineering problems, like most Earth science problems, are mainly “inverse problems,” which start with a set of observations or results and then tries to calculate the factors that caused or produced them. Dealing with the uncertainties that arise from these problems is the everyday challenge of the petroleum engineer. My new book, Petroleum Engineering: Principles, Calculations, and Workflows, just published by AGU, describes an integrated workflow approach to addressing these problems.
Petroleum engineers can generally be classified into two types—reservoir engineers and production engineers—who are involved in various tasks at different stages of the petroleum resource life cycle.
At the exploration phrase, the main objective is to find new reservoirs of hydrocarbons. This begins with acquisition and interpretation of geological and geophysical data to identify structural and rock characteristics that relate to petroleum systems. Where potential hydrocarbon resources are identified, the reservoir engineer will design and carry out a well test, analyze rock and fluid samples, estimate the quantity of hydrocarbons that are recoverable, make an assessment of commercial viability, and advise on future well placement for optimized results.
During the production phase, the primary objective is to extract hydrocarbons at maximum or optimized capacity. Production engineers are responsible for managing the interface between the reservoir and the well. Their role is to understand the well’s characteristics and ensure that hydrocarbon can flow to the surface through production tubing, as well as identifying how to harness energy in the production system and diagnosis of production problems.
Of course, that all sounds like a relatively simple and straight-forward process, but the calculations relating to both the exploration and production phrase are fraught with uncertainties. Uncertainties arise because any calculation relies on measured parameters derived from explicit or implicit relationships between other variables; inaccuracies in any of these variables can introduce a wide range of uncertainty into the calculations.
For example, a petroleum engineer may need to characterize a large hydrocarbon reservoir based on limited data extracted from just a few bore holes; the engineer needs to appreciate how the limited measurements introduce a range of uncertainties into their calculations of overall reservoir characteristics.
I believe that the best approach to reducing the wide range of uncertainties in petroleum engineering calculations is integrated workflows. This combines one or more approach not only to reduce the uncertainties but also to improve repeatability, reliability and accuracy.
For example, the material balance method is an important technique used by petroleum engineers to predict petroleum reservoir performance, including reserve calculation, reservoir drive mechanisms characterization, and production forecasting. Material balance involves using cumulative reservoir fluid withdrawal and/or injection with average reservoir pressure to model and predict reservoir performance with or without a geological model. The material balance technique is an inverse problem, thus fraught with uncertainties. To reduce uncertainty in using this technique, the workflow should include a data preparation processes, model diagnosis, defining system model and initial model parameter, model consistency check, forward simulation, and regression.
I wanted to compile this book to fill various gaps in the resources currently available. Most teaching techniques are focused on petroleum engineering principles and calculations with less emphasis on how these principles can be used for solving practical problems during different stages of petroleum resource development. Many teaching methods also present petroleum engineering calculations as direct problems rather than inverse problems, hence not emphasizing the associated non-uniqueness and uncertainty.
Furthermore, teaching books have not emphasized how different methods can be combined in an integrated approach, for example using workflows to harness the capabilities of each method or mathematical principle in order to improve accuracy and limit uncertainty in calculations and modeling.
This book is based on my years of experience in training graduates and professionals in the oil and gas industry. I hope that it will be a useful practical resource for a wide community of geoscientists, earth scientists, exploration geologists, and engineers.
Petroleum Engineering: Principles, Calculations, and Workflows, 2018, 528 pp., ISBN: 978-1-119-38797-8, list price $249.95 (hardcover), $199.99 (e-book)
—Moshood Sanni (Mos[email protected]), PetroVision Energy Services, London, UK
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