Oil & Gas - Maximising Recovery Programme (formerly SHARP) IOR Views

Modelling the Uncertainty and Risks Associated with the Design and Life Cycle of CO2 Sequestration in Coalbed Methane Reservoirs (GR/S27313/01)

The concentration of CO2 in the Earth's atmosphere has increased significantly over the last fifty years. Projected increases in energy use by developing countries are expected to exacerbate this problem as more fossil fuels are converted to CO2. This trend demands that carbon resources are managed more efficiently and aggressively. Increases in energy efficiency will help mitigate but not eliminate the problem and the low energy-delay and high cost of alternative energy sources suggest we will continue to depend on fossil fuels well into the 21st century. Carbon sequestration can significantly contribute to reversing this trend. The idea of sequestering CO2 in geologic formations is relatively new. Depleting oil reservoirs and in unmineable coal beds have the highest near-term potential for storing CO2 due to their large and geologically diverse storage capacity, as well a: strong base of industrial experience with injecting CO2 into depleting oil reservoirs. For unmineable coal seams, current research is focused on understanding the fundamental CO2 adsorption mechanisms and the effects of CO2 injection on the permeability of the coal seams. Research can also ensure that CO2 storage in geologic formations is safe and environmentally secure. The main objective of this research is to quantify the uncertainties associated with reservoir performance during and after CO2 injection in order to establish a methodology for the design, prediction and risk evaluation of safe and environmentally sound CO2 storage in coal seam reservoirs.

The Principal Investigator is Dr A Korre of the Environmental, Science & Technology Department at Imperial College, London. Project Partner is the Alberta Research Council. The project started in February 2004 and is due to be completed by January 2007. The award value is £127k.

Micro Mechanical Studies of Sand Production Problems in Wellbores (GR/S82510/01)

Sand production is one of the most severe wellbore problems in the petroleum industry. Despite its critical importance and previous research input, the mechanisms of sand production have not been fully understood because of its complexity. Studies aimed at predicting sand production have predominantly addressed the more readily observable transient and catastrophic types of sand production, few studies have addressed the modelling of the continuous sand erosion process, which is of great importance in practice. In this project, experimental and numerical modelling methods are proposed to elucidate the micro mechanical factors in sand production. Proposed experimental work will include parametric studies of the onset of sand erosion, the initiation of the dislodgement of sand, and the rate of sand production under various flow, stress and saturation conditions. Then a CFD/DEM coupled numerical method will be developed incorporating new capillary models with the consideration of water breakthrough, to simulate the dynamic process of the dislodgement of sand particles, the formation of micro cavities, and eventually the whole sand production process. The research will provide a theoretical understanding of the mechanisms of sand production, criteria to identify the onset of erosion of the sandstone and the propagation of sand production under various conditions, and a 3D numerical tool to predict the initiation, propagation, and rate of sand production.

The Principal Investigator is Professor C J Lawrence of the Department of Chemical Engineering & Chemical Technology at Imperial College, London. Other investigators are Professor M J Blunt, Dr F Stepanek and Dr Y Sheng. Project Partner is Schlumberger Cambridge Research Ltd. The project will start in June 2004 and is due to be completed by May 2007. The award value is £203.5k.

Molecular Simualtion of Gas-Liquid Interfaces Relevant to Gas Hydrate Formation (GR/S12005/01)

Gas hydrates of natural gas are an expensive problem to the oil and gas industry, where gas hydrates form and very quickly block gas transmission lines. Traditional gas hydrate inhibition methods are not efficient in preventing hydrate formation in deepwater pipelines, and as much as 60 wt% of these inhibitors are required in areas such as the North Sea. The proposed work represents the first use of molecular simulation methods to investigate gas hydrate formation at an interface and will focus on the interface between liquid water and hydrate-forming gases under appropriate conditions for gas hydrate formation. The hydrate-forming gases of interest are methane and propane, as these are the major components of natural gas, and also individually form the two most common gas hydrate crystal structures. Molecular dynamics simulations will be used to investigate the structure of the interface between liquid water and these two gases, and mixtures of these two gases. Transport of gas molecules through and within the interfacial region will be monitored. The potential for these gas molecules to cross the interface and to agglomerate within the interface will be calculated using the free energy perturbation method. The outcomes of this work will help hydrate-related industries develop new methods of hydrate inhibition and promotion through a detailed understanding of the mechanisms through which gas hydrates form.

The Principal Investigator is Dr R Westacott of the School of Engineering & Physical Science at Heriot-Watt University. The project started in April 2004 and is due to be completed by April 2005. The award value is £114k.

Higher Resolution Wave-Oriented Upwind Schemes for Conservation Laws with Emphasis on Flow in Porous Media (GR/S70968/01)

Development of both higher-dimensional and higher-order methods for reservoir simulation on general unstructured grids is proposed. Currently standard first order single-point upstream weighting methods are employed in reservoir simulation for integrating the essentially hyperbolic system components. These methods introduce both coordinate-line numerical diffusion (even in 1D) and cross-wind diffusion into the solution that is grid and geometry dependent. These effects are particularly important when steep fronts and shocks are present and for cases where flow is across grid coordinate lines. Rather than upwind along coordinate lines, new higher-dimensional schemes are proposed that upwind in the direction of the wave paths in order to minimise crosswind diffusion. Higher-order schemes are also proposed for multiphase-flow reservoir systems in 2D and 3D on general unstructured grids. The dual development will lead to new schemes for unstructured grid reservoir simulation that provide sharp reliable estimates of key oil recovery parameters by minimising crosswind and directional diffusion effects. The new schemes will be tested across a spectrum of typical flow regimes, for a range of mobility ratios, gravity numbers, heterogeneous permeability tensors and grid types.

The Principal Investigator is Dr M G Edwards of the Department of Civil Engineering at the University of Wales, Swansea. Other investigators are Professor K Morgan and Professor N P Weatherill. The project started in May 2004 and is due to be completed by April 2007. The award value is £222k.