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Matrix compressibility, shrinkage and swelling can cause profound changes in porosity and permeability of coalbed during gas sorption and desorption. These factors affect the distribution of pressure, methane production and CO 2 sequestration.This paper compares the effects of cleat compression and matrix shrinkage and swelling models with the injection of different compositional gas mixtures (CO 2 and N 2 ). It shows that well performance, pressure distribution and properties of the seam are strongly affected by matrix shrinkage and swelling. Matrix shrinkage and swelling also affects net present value of the enhanced coalbed methane recovery scheme. In order to select the best enhanced coalbed methane recovery schemes, economic evaluation and sensitivity studies are necessary.

Uncommon and untested biopolymers in field pilot studies, but applied in laboratory studies are combined with Al 2 O 3 nanoparticles to form nanocomposites for enhanced oil recovery (EOR) performance evaluation. Core plug samples of the Niger Delta region and Berea sandstone were used as the porous media for EOR experiments. Incremental oil recovery sequel to waterflooding (secondary recovery) was 5 -12 % and 5 -7% for potato starch nanocomposite (PSPNP) and gum arabic nanocomposite (GCNP) respectively. The biopolymer nanocomposites showed improved viscosity over the biopolymers. Thus, the nanoparticle served as a viscosity modifier on one-hand and stability enhancer on the other.EOR was affected by biopolymer and nanoparticle concentration with the attendant catch-22 situation of permeability impairment. The overall higher incremental recovery of applying PSPNP came by an intermediate potato starch (PSP) flooding between waterflooding and PSNP flooding. Consequently, slugs of biopolymer and biopolymer nanocomposite may be the way forward knowing that the biopolymers studied have surface-active constituents.

The Capacitance-Resistance Model (CRM) is a semi-analytical modelling approach utilizing non-linear multivariate regression. Using historical production and injection rates, as well as historical bottomhole pressure data if available, CRM quantifies the connectivity and degree of fluid storage between injectors and producers in a reservoir. The CRM has been applied to waterflood management and performance prediction, improved reservoir characterisation, waterflood optimisation and, production optimisation. In this study, the CRM was used in fault characterisation and flow barrier detection. Historical production and injection data from an oilfield from the "Far East" were then used to calibrate the CRM. Thereafter, the resulting CRM parameters were combined with geological data and wells data to characterise two major faults in the reservoir, as well as detect other flow barriers within the reservoir. Based on the results, several sections of one fault have varying degrees of communication. There were also smaller flow barriers within the reservoir section considered around this fault, that negatively impacted the performance of some injectors. The second fault was mostly sealing, with few leakages along the extent of the fault. Capacitance-Resistance Modelling can be used to corroborate the results of Interference Testing, Tracer Test and 4D Seismic in detecting and characterising faults, and as a cost-effective reservoir management tool.