Technology Focus: Reservoir Surveillance (September 2021)

Abstract

It is not unusual to compare a team of subsurface professionals to a team of detectives piecing together a sequence of events to solve a crime. To make sense of what is happening in a hydrocarbon reservoir, subsurface teams, like detectives, typically have incomplete, sparse data sets, sampled at different points in time and space. The data only provide a partial picture of what has happened and what is likely to happen in the future. In either case, surveillance is an essential tactic to build a mental model of the situation. Fortunately, both detectives and subsurface teams have growing surveillance toolboxes to help fill information gaps and narrow the range of possible scenarios. In the oil and gas industry, an endless set of questions can be asked to characterize the state and history of a hydrocarbon reservoir. Teams need to understand the capability of the reservoir to store fluids, stresses acting on the reservoir, what fluids exist and how they interact with each other and the rock, and how fluids are moving (or are likely to move) through the reservoir. Information, however, is rarely free, and different surveillance tools provide varying qualities of information, so it is essential for subsurface professionals to choose wisely in terms of which problems to solve and which tools to pull out of the toolbox. Ultimately, we need to apply the right tools to the right problems to maximize the value of the information we gather. In this feature, we will explore innovative approaches to help better understand the stress state of the reservoir, interactions between different fluids and rocks, and how to track the movement of specific fluid components throughout the reservoir. To do so, the authors of the papers highlighted in this month’s feature apply advanced log data analysis, experimental laboratory work, and compositional reservoir simulation, key tools that every subsurface team should have in its toolbox. Recommended additional reading at OnePetro: www.onepetro.org. SPE 201679 - A Fast Method To Estimate the Correlation Between Confining Stresses and Absolute Permeability of Propped Fractures by Faras Al Balushi, The Pennsylvania State University, et al. SPE 202224 - Downhole Surveillance During the Well Lifetime Using Distributed Temperature Sensing by Ludovic Paul Ricard, CSIRO, et al. SPE 201635 - Predicting Reservoir Fluid Properties From Advanced Mud Gas Data by Tao Yang, Equinor, et al.