Investigating CO<Subscript>2</Subscript>-enhanced oil recovery potential for a mature oil field: a case study based on Ankleshwar oil field,Cambay Basin,India

CO₂-enhanced oil recovery (EOR) is an upcoming technology in India. At present, no Indian field is under CO₂-EOR and implementation of this technique to a mature oil field needs a rigorous study. In the present work, we made an attempt to investigate the CO₂-EOR potential of a mature oil field, situated in Cambay Basin, India. The field was put on production in 1961, and it has produced approximately 65.36 MMt oil during massive water flooding, leading to residual oil reserves of 6.49 MMt. The operator of the field is interested in incremental oil recovery from this field by injecting CO₂. This requires estimation of incremental oil recovery potential of the field by carrying out systematic study. We, therefore, developed a conceptual model inspired by Ankleshwar oil field of Cambay Basin using available information provided by the field operator and carried out systematic studies to establish an optimized strategy for CO₂ injection. To achieve this goal, we investigated the effect of various operational parameters on oil recovery efficiency of our conceptual model and selected optimum parameters for reservoir simulations. Simulation results clearly indicate that the field can be a good candidate for CO₂-EOR, and an additional oil recovery of 10.4% of hydrocarbon pore volume is feasible. Major outcome of the study is an optimized black-oil simulation model, which is in good agreement with the fine grid compositional model of high accuracy. The proposed black-oil model can easily be implemented and updated compared with compute intensive finer compositional simulation model.     

EQUATIONS FOR GRAIN SIZE DISTRIBUTION CURVE

The grain size distribution of particulate material is of particular interest in the field of sediment transport. The size distribution is described by various equations, however no equation is flexible enough to satisfy the grain size distribution data faithfully. Presented herein are the equations for unimodal and multimodal grain size distribution curves. A graphical method has been given to evaluate the parameters involved in these equations. The size distribution equation can be used to estimate many properties of sediment sample like number of sediment particles, surface area of the particles and hydraulic conductivity. It is hoped that the equations will find many applications in studying sedimentation processes.     

A two-track CDM: improved incentives for sustainable development and offset production

The Clean Development Mechanism (CDM) has been criticized in the literature for encouraging a focus on offset production (OP) at the expense of achieving or encouraging sustainable development (SD). It is argued that one explanation for this is that there is no commonly agreed definition of SD and, moreover, the priority of CDM project developers is often to produce cost-effective OP. Many of the proposals to address these drawbacks are not politically feasible. It is argued that the CDM should be split into a two-track mechanism, with one track for offset production and the other for offset production with an emphasis on sustainable development benefits. This would enable the political deadlock to be broken, allow the inclusion of SD benefits in the price mechanism itself, and allow both SD and OP objectives to be simultaneously achieved.

Policy relevance

The CDM has been criticized for failing to achieve its sustainable development objective, for verification problems regarding the mitigation effects of projects’ emissions, for being complex and bureaucratic, and for the very limited participation by the least developed countries. Given the adoption of a second period of the Kyoto Protocol and the discussion of new market mechanisms in the context of negotiating a new global climate agreement to be adopted in 2015, it is time to explore the ways in which the CDM might be reformed. A two-track version of the CDM is proposed, with one track focused on credit (offset) production and the other track focused on sustainable development. This system could improve the incentive for achieving sustainable development, reduce the uncertainty regarding whether real emissions reductions have been achieved, and be attractive to both developing and industrialized countries.