Prospectus re Admission to the Official List - Heritage Oil

RPS EnergyHeritage Oil – Competent Persons ReportFigure 21:Average Reservoir Pressure from Full Field Simulation22FEB200803404094Heritage has used a ‘‘downside’’ geological scenario in the simulator, as is necessary for the developmentplan submitted to the authorities. The above output shows oil rate building up to some 1,200 m 3 /d(7,548 stb/d) following water injection which builds to a peak rate of 2,800 m 3 /d (17,611 bbl/d). This rateeventually far exceeds voidage and the reservoir is re-pressurised (Figure 21), although in practice it is notnecessary to exceed initial reservoir pressure. This case consists of a total of 49 producers, and 32 injectors,as shown below in the drilling schedule for the Company’s ‘‘p90’’ and ‘‘p50’’ cases.2007 2008 2009 2010 2011 2012 2013 2014 2015p90New Producers ....................... 2 4 8 16 16 2Cumulative Producers .................. 3 7 15 31 47 49New Injectors ........................ 4 8 8 12Cumulative Injectors ................... 0 0 4 12 20 32Total in Year ..................... 2 4 12 24 24 14p50New Producers ....................... 2 4 8 16 14 14 13 10 2Cumulative Producers .................. 3 7 15 31 45 59 72 82 84New Injectors ........................ 4 8 8 8 9 8 1Cumulative Injectors ................... 0 0 0 8 16 24 33 41 46Total in Year ..................... 0 4 12 24 22 22 22 18 3Table 19:The p90 and p50 Drilling Schedule for Zapadno ChumpasskoyeThe simulation work is reasonable, but of course is not matched to a sustained period of history (and isthus less reliable than it will be once more performance data become available). The two producers have(to the effective date) produced some 0.048 MMstb. Some of the rates achieved by wells in the simulatorsurpass those rates seen in the field to date, albeit in just two wells. We have used the above drillingschedule, the rate build-up from the simulator, but reduced rates to construct a production profile for our1P case; we have also allowed for downtime that is likely to occur to well, pump, facility, and pipelineavailability.102