Reservoir Geomechanics In situ stress and rock mechanics applied to reservoir processes! " Reservoir Geomechanics It is critical to understand the mechanical behaviour of a reservoir to make optimal decision throughout the life of a field. SPE-50939-PA. Settari, A. and Price, H.S. et al. Proc., 38th U.S. Rock Mechanics Symposium, Washington, DC. Conference on North Sea Oil and Gas Reservoirs, Trondheim, Norway, 201–211. The Finite Element Method in the Deformation and Consolidation of Porous Media, 344. Such models have been used extensively to study permeability changes in waterfloods, particularly in fractured or jointed media. SPE Res Eval & Eng 2 (2): 186-195. One-Way Coupled Reservoir-Geomechanical Modeling of the Lost Hills Oil Field, California. In Situ Stress and Rock Mechanics Characterization. Iteration is carried out between the reservoir and stress solution at every timestep until the pore volumes and permeabilities calculated from the stress model and those used by the reservoir model agree. 1975. ... leak-off coefficient and Poisson's ratio. This method is shown schematically in Fig. Mean Pressure Stanford|ONLINE gp202.class.stanford.edu#! The changes of permeability are also iterated on. While the need for the tensor transmissibilities in such models has been recognized, in injection processes dual-porosity media can be created. GeoMechanics is the theoretical and applied science of the mechanical behavior of geological material. The Bachaquero Study - A Composite Analysis of the Behavior of a Compaction Drive/Solution Gas Drive Reservoir. et al. Numerical Simulation of Oil Production With Simultaneous Ground Subsidence. Day 1. The purpose of this paper is to develop a new formula for porosity as a function of pressure, temperature, and mean total stress, which is used to improve the speed of convergence of the coupling between a geomechanics module and a reservoir simulator when iterative coupling is employed. Models which preserve all of the key complexities. Lewis, R.W. Understanding your reservoir empowers you to better optimize its lifetime performance. Reservoir parameters that include: formation porosity, permeability and bottom hole pressure can be derived from geomechanical evaluation. Again, the traditional approach is to use tables of k vs. pressure in an uncoupled model. Two to three orders of magnitude enhancements in permeability can occur because of injection at fracture pressure (e.g., in microfractured rock or coal seams). New Iterative Coupling Between a Reservoir Simulator and a Geomechanics Module. Presented at the SPE Annual Technical Conference and Exhibition, Houston, Texas, 3–6. 3D Reservoir Simulation of Ekofisk Compaction Drive (includes associated papers 24317 and 24400 ). A Coupled Reservoir and Geomechanical Simulation System. Reservoir Geomechanics. However, the changes in porosity and permeability are more pronounced when rock failure occurs, such as in compacting reservoirs or in high-pressure injection operations, and these processes require use of more complex, coupled geomechanical modeling. Distinguished Author Series, J Pet Technol 54 (8): 62–69. Pore volumes and permeabilities in the flow model are computed as a function of p, T, and σavg with stress variables lagged a timestep. You must log in to edit PetroWiki. Chichester, England: John Wiley and Sons. Society of Petroleum Engineers Journal 15 (5): 411-424. The stress path affects the geomechanical behavior of the reservoir in terms of compaction and associated surface subsidence. 4). Combining geomechanics and ﬂow in multiphase ﬂow settings showed that production decrease could be caused by a combination . Rock mechanics is coupled with fluid flow in two aspects. The fourth section discusses microseismicity, particularly microseismic event generation. 1 – Schematic of the iterative coupling algorithm. Reservoir Geomechanics Stefan Hergarten Institut fur Geo- und Umweltnaturwissenschaften Albert-Ludwigs-Universit at Freiburg . The main types of models (in the order of increasing rigorousness, but also computing time) are as follows: Pressure and temperature changes are passed from the reservoir code to the geomechanics module, but no information is passed back on timestep basis. SPE-65107-MS. Sulak, R.M., Thomas, L.K., and Boade, R.R. This process has been also modeled by the "compaction-dilation" tables. Compaction can be a drive mechanism 4. In stress modeling, the changes in volumetric strain and porosity are calculated from complex constitutive relations of the material, which define both the stress-strain and volumetric behavior. However, the problem is somewhat easier because stress-dependent permeability (or transmissibility) does not affect mass-balance formulation. J Pet Technol 43 (10): 1272-1278. The tensor character of permeability may be important in these applications. Settari, A., Walters, D.A., and Behie, G.A. Another application is the prediction of production/injection-induced slippage on faults, which can induce communication between reservoir fault blocks and/or seismicity.  Here, the advantage of coupled modeling is in its capability to predict the permeability changes from the geomechanics of reopening of fractures or failure (dilation) of joints. The same principles can be also applied to model hydraulically induced fractures being represented by dynamically changing transmissibility multipliers in the potential fracture plane.  Generally, the reservoir simulator is the "host" or "master." The relation between reservoir compaction and surface subsidence can be then obtained by an independent solution of a stress problem using the computed compaction as a boundary condition. Any formation/reservoir geomechanical assessment starts with characterizing the stresses, strength and pressure profiles. Advances in Coupled Geomechanical and Reservoir Modeling With Applications to Reservoir Compaction. It is used to reduce risks and optimize rewards related to the mechanical failure of the reservoir, over, side and under burden formations due to oil and gas exploration and production activities. SPE 97155. 1976. Reservoir Geomechanics This interdisciplinary course encompasses the fields of rock mechanics, structural geology, earthquake seismology and petroleum engineering to address a wide range of geomechanical problems that arise during the exploitation of oil and gas reservoirs. Permeability of the media is also a function of effective stresses in the reservoir. PETSOC-2000-078. 2005. 1995. Presented at the International Oil and Gas Conference and Exhibition in China, Beijing, China, 7–10 November. This means that stresses in the subsurface are not static through time nor can these be characterized similarly everywhere at present day. Historically, reservoir simulation has accounted for rock mechanics by simple use of a time-invariant rock compressibility cR , spatially constant or variable. Conventional reservoir simulation studies ignore numerous constraints placed on the development scenarios from the point of view of drilling, completion, and operations. 2000. 1992. where Vp is the pore volume of the element. This interdisciplinary book encompasses the fields of rock mechanics, structural geology and petroleum engineering to address a wide range of geomechanical problems that arise during the exploitation of oil and gas reservoirs. One of the most complete books on Reservoir Geomechanics!! 1999. The majority of coupled models use a conventional finite-difference reservoir simulator coupled with a finite-element (FEM) stress simulator. SPE Res Eng 4 (4): 422–428. Presented at the SPE Annual Technical Conference and Exhibition, San Antonio, Texas, 4-7 October 1981. Use of a scientific computing program such MATLAB, Python, or Microsoft Excel is necessary for manipulating and visualizing data. The deformation of the rock solid (also called the skeleton) caused by combination of stress and pressure changes results in changes in the bulk volume of an element Vb, which is computed at any conditions as, where εv is the volumetric strain at these conditions, and Vb0 is the bulk volume at reference conditions at which the volumetric strain = 0. This allows geoscientists and engineers to assess and mitigate potential geomechanics problems affecting well and completions, stimulation, production, injection, and field management. We deliver characterization models incorporating all the characteristics of the reservoir that are pertinent to its ability to store and produce hydrocarbons, including petrophysics, geology, geomechanics, and geophysics. https://petrowiki.spe.org/index.php?title=Geomechanics_in_reservoir_simulation&oldid=51623, Copyright 2012-2021, Society of Petroleum Engineers, time, time units or transmissibility, md•ft/cp, Porosity changes are a direct result of the deformation of the skeleton, which is a complex function of both pressure and stress (effective stress state). Geomechanics also helps engineers to model fluid movement and predict how fluid removal or injection leads to changes in permeability, fluid pressure, and in situ rock stresses that can have significant effects on reservoir performance. Doing that requires the most accurate measurements available from multiple sources and disciplines to prepare a superior quantitative representation of the reservoir. 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