The increasing demand for hydrocarbons and decreasing reserves have created the necessity to produce oil and gas more efficiently and economically. Increasingly, oil and gas companies are focusing on unconventional hydrocarbons; oil sands, shales and CBM. For this class of reservoir materials, the geomechanical response of the reservoir can play an important role in the recovery process. For naturally fractured, stress sensitive reservoirs or thermal recovery processes, geomechanical processes play an even greater role in efficient, economic recovery. For simulations of these processes, most research efforts have been focused on reservoir geomechanical simulations using conventional reservoir simulators coupled to geomechanical codes. While coupled reservoir-geomechanics modeling has been recently widely studied in the literature, there is no applicable methodology implemented or proposed to mitigate the challenging computational cost involved with the inclusion of geomechanics in large multimillion-cell reservoirs. Past studies so far have focused on different coupling schemes, but not on the efficient and robust simulation workflows. This research was conducted with the aim of development and application of various different strategies to include geomechanics into reservoir simulation workflows in large scale reservoirs and in a timely fashion process. The research was performed to allow the future simulators to perform high resolution reservoir-geomechanical simulations in a large scale (near field and far field) with long simulation time windows and lowest computational cost. Initially, analytical proxies were developed and recommending for implementation in lieu of complex reservoir simulations. The analytical model was for prediction of heavy oil geomechanical responses everywhere in the reservoir. The model adopted the use of the mathematical domain decomposition technique and a novel temperature front tracking developed in the very early stage of the research. As opposed to classical analytical models, the proxy predicted reservoir flow and mechanical behavior (on a synthetic case geometry with real hydraulic data) everywhere in the reservoir and in dynamic and transient flow regimes. Subsequent research was aimed at reservoir-geomechanics coupled model order reduction by use of a numerical proxy. The proxy took advantage of streamline linear space behavior and power in decomposition of the reservoir domain into sub-systems (delineation/drainage areas). The combination of localization and linearization allowed predicting both mechanical and fluid flow responses of the reservoir with only solving the pressure equation in Cartesian underlying 3D grids and the solution of saturation transport equation along only one streamline. Following this, a streamline-based reservoir-geomechanics coupling was proposed and was implemented within a Fortran-C++ based platform. The new developed technique was compared in terms of computational cost and results accuracy with the conventional hydromechanical coupling strategy that was developed on a C++ based platform by use of collocated FV-FEM discretization scheme. One of the final stages of the research explored different streamline-based reservoir-geomechanics coupling strategies for full-field reservoir simulations. Various coupling strategies including sequential coupling schemes and a semi-fully coupling scheme to embed geomechanics into streamline simulation workflow was developed and performed. Numerical software with advanced GUI was coded on QT programming language (C++ based) developed to couple mechanical simulator to streamline simulation engine. While streamline simulations were the center of the research, the last stage of research was conducted on numerical and physical stability, convergence and material balance errors of SL-based reservoir-geomechanics class of couplings. The results provided a solid foundation for proper selection of time-steps in SL-based coupling to ensure a numerically stable and physically robust hydromechanical simulation. As a result we showed that use of streamline simulation in both proxy forms and simulator forms have significant added value in full-field reservoir-geomechanics simulations.
Author: Victor N. Nikolaevskiy
Publisher: Springer Science & Business Media
Release Date: 1995-12-31
This monograph is based on subsurface hydrodynamics and applied geomechanics and places them in a unifying framework. It focuses on the understanding of physical and mechanical properties of geomaterials by presenting mathematical models of deformation and fracture with related experiments.
Designing an efficient drilling program is a key step for the development of an oil and/or gas field. Variations in reservoir pressure, saturation and temperature, induced by reservoir production or CO2 injection, involve various coupled physical and chemical processes. Geomechanics, which consider all thermohydromechanical phenomena involved in rock behavior, play an important role in every operation involved in the exploitation of hydrocarbons, from drilling to production, and in CO2 geological storage operations as well. Pressure changes in the reservoir modify the in situ stresses and induce strains, not only within the reservoir itself, but also in the entire sedimentary column. In turn, these stress variations and associated strains modify the fluids flow in the reservoir and change the wellbore stability parameters. This book offers a large overview on applications of Geomechanics to petroleum industry. It presents the fundamentals of rock mechanics, describes the methods used to characterise rocks in the laboratory and the modelling of their mechanical behaviour ; it gives elements of numerical geomechanical modelling at the site scale. It also demonstrates the role of Geomechanics in the optimisation of drilling and production : it encompasses drillability, wellbore stability, sand production and hydraulic fracturing ; it provides the basic attainments to deal with the environmental aspects of heave or subsidence of the surface layers, CO2 sequestration and well abandonment ; and it shows how seismic monitoring and geomechanical modelling of reservoirs can help to optimise production or check cap rock integrity. This book will be of interest to all engineers involved in oil field development and petroleum engineering students, whether drillers or producers. It aims also at providing a large range of potential users with a simple approach of a broad field of knowledge.
Author: G. Dresen
Publisher: Springer Science & Business Media
Release Date: 2008-01-24
Mechanical properties and fluid transport in rocks are intimately linked as deformation of a solid rock matrix immediately affects the pore space and permeability. Part I of this topical volume covers mainly the nucleation and evolution of crack damage in rocks, new or modified techniques to measure rock fracture toughness and a discussion of upscaling techniques relating mechanical and fluid transport behaviour in rocks at different spatial scales.
Author: John W. Bull
Publisher: CRC Press
Release Date: 2003-09-02
In geomechanics, existing design methods are very much dependent upon sophisticated on-site techniques to assess ground conditions. This book describes numerical analysis, computer simulation and modelling that can be used to answer some highly complex questions associated with geomechanics. The contributors, who are all international experts in the field, also give insights into the future directions of these methods. Numerical Analysis and Modelling in Geomechanics will appeal to professional engineers involved in designing and building both onshore and offshore structures, where geomechanical considerations may well be outside the usual codes of practice, and therefore specialist advice is required. Postgraduate researchers, degree students carrying out project work in this area will also find the book an invaluable resource.
Author: S. J. Jolley
Publisher: Geological Society of London
Release Date: 2007-01-01
This volume reviews our current understanding and ability to model the complex distribution and behaviour of fault and fracture networks, highlighting their fluid compartmentalizing effects and storage-transmissivity characteristics, and outlining approaches for predicting the dynamic fluid flow and geomechanical behaviour of these reservoirs. This collection of 25 papers provides an overview of recent progress and outstanding issues in the areas of structural complexity and fault geometry, detection and prediction of faults and fractures, compartmentalizing effects of fault systems and complex siliciclastic reservoirs and critical controls affecting fractured reservoirs.
Author: Gilles Pijaudier-Cabot
Publisher: John Wiley & Sons
Release Date: 2013-01-29
Genre: Technology & Engineering
CO2 capture and geological storage is seen as the most effective technology to rapidly reduce the emission of greenhouse gases into the atmosphere. Up until now and before proceeding to an industrial development of this technology, laboratory research has been conducted for several years and pilot projects have been launched. So far, these studies have mainly focused on transport and geochemical issues and few studies have been dedicated to the geomechanical issues in CO2 storage facilities. The purpose of this book is to give an overview of the multiphysics processes occurring in CO2 storage facilities, with particular attention given to coupled geomechanical problems. The book is divided into three parts. The first part is dedicated to transport processes and focuses on the efficiency of the storage complex and the evaluation of possible leakage paths. The second part deals with issues related to reservoir injectivity and the presence of fractures and occurrence of damage. The final part of the book concerns the serviceability and ageing of the geomaterials whose poromechanical properties may be altered by contact with the injected reactive fluid.
The Steam Assisted Gravity Drainage (SAGD) process is a thermal enhanced oil recovery (EOR) method that appears tremendously successful, especially for bitumen. SAGD process results in a complex interaction of geomechanics and multiphase flow in cohesionless porous media. In this process, continuous steam injection changes reservoir pore pressure and temperature, which can increase or decrease the effective stresses in the reservoir. Quantification of the state of deformation and stress in the reservoir is essential for the correct prediction of reservoir productivity, seal integrity, hydro fracturing, well failure and also for the interpretation of 4D seismic used to follow the development of the steam chamber. In SAGD process, the analysis of reservoir-geomechanics is concerned with the simultaneous study of fluid flow and mechanical response of the reservoir. Reservoir-geomechanics coupled simulation is still an important research topic. To perform this kind of simulation, a solution is to use a finite element based simulator to describe geomechanics and a finite volume based simulator to describe fluid flow. In this thesis, the SAGD coupled thermo-hydro-mechanical modelling is conducted using PumaFlow reservoir simulator and Abaqus as the geomechanical simulator. The main issues being investigated in this study were (1) the coupling strategy, (2) the geometry and (3) type of gridding system. This work was performed on synthetic cases.
Author: James P. Verdon
Publisher: Springer Science & Business Media
Release Date: 2012-01-11
This thesis by an award-winning researcher summarizes the potential to use passive seismic methods to monitor the sequestration of anthropogenic CO2 in geologic reservoirs. In doing so it synthesizes innovative research in both seismology and geomechanics.
Author: C. David
Publisher: Editora 34
Release Date: 2007-01-01
The study of reservoir and repository performance requires the integration of many different fields in Earth sciences, among them rock physics and geomechanics. The aim of this book is to emphasize how rock physics and geomechanics help to get a better insight into important issues linked to reservoir management for exploitation of natural resources, and to repository safety assessment for hazardous waste storage in geological environment. The studies presented here deal with the hydromechanical coupling in fractured rocks, the key experiments in safety assessment of repositories, the development of damaged zones during excavation in a shaley formation, the influence of temperature on the properties of shales, the poroelastic response of sandstones, the development and propagation of compaction bands in reservoir rocks, imaging techniques of geomaterials, the characterization and modelling of reservoirs using 4D seismic data, the mechanical behaviour of fractured rock masses, the petrophysical properties of fault zones, models for rock deformation by pressure solution and the elastic anisotropy in cracked rocks.