Prospectus re Admission to the Official List - Heritage Oil

RPS EnergyHeritage Oil – Competent Persons ReportFigure 18:27FEB200804274190Illustration of Inverted Five-spot Patterns at Zapadno ChumpasskoyeThe well count will be built up over the next few years, The current plan to maintain reservoir pressure isto inject water injection at high voidage replacement ratios (‘‘VRR’’s) (in excess of 1) to re-pressure thereservoir. Wells will be drilled from well pads, with maximum step-out from the surface location of 1.5 km.4.4.4. Recovery MechanismsWhist under natural depletion, wells will produce through oil expansion with perhaps some aquifer influx.It is unlikely that reservoir pressure will reach the bubble point at any point in the reservoir before waterinjection commences, so solution gas drive will not be developed. Once water injection commences,planned at VRR in excess of 1, the unfavourable mobility ratio will cause some of the water to createviscous fingers through the oil leg. Consideration is being given to the optimum reservoir pressurefor flooding.100