1. Production Efficiency Guidance notes January 2010

2. Contents Metric Principles Definitions –Production efficiency components –Total Annual throughput –Well potential –Plant potential –Export potential –Market potential –Structural Maximum Production Potential (SMPP) –Summary of Field Production measures Gas Balance Production Constraints –Oil & Gas field –Gas field producing under contract

3. PE Guideline - Metric Principles –The intention of the Production Efficiency (PE) metric is to provide a tool to help make improvements to production performance, by creating a standard to: Benchmark operations against Quantify the size and value of operational excellence opportunities Show the primary areas to improve performance on each metric –PE is an objective metric, not a subjective one, so 100% PE would imply “perfect” operations, such that additional production could only be achieved through structural changes. Structural changes require either further investment to increase the Structural Maximum Production Potential (SMPP) or negotiating additional Market Maximum Production Potential (MMPP)

4. Definitions: PE Components Structural Maximum Production Potential Structural Maximum Production Potential (SMPP) is the lowest structural production potential of the well, plant and export systems including third party processed volumes*. Structural MPP is the sum over the year of the monthly MPP figures evaluated at the beginning of each month. Well production potential is the sum of the individual operating well flow rates tested at the optimum operating conditions plus the sum of the third party forecast well potential. Plant production potential is the maximum monthly throughput potential measured daily, including third party forecast throughput. Export potential is the maximum monthly physical potential available through ships and/or pipeline measured daily, including third party forecast throughput. Market Potential (applicable only to gas fields producing under contract) is the sum of the daily contract nominations for the month. * Third party processed volumes include only processed flows and not ‘up and over’ flows

5. Definitions: Annual throughput definition Total annual throughput This is the total processed throughput which is delivered to the export* system. It includes third party volumes which undergo processing at the production facility, but not "up and over" volumes which pass through without being processed. Total annual throughput =annual oil production (including condensate and NGL if not included in gas) +oil processed for third parties +wet gas exported* (exported gas including NGL if not included in oil, but excluding flare). This will also include any third party gas. * For gas production, export system means all gas that is delivered off the production facilities i.e. the sum of gas exported to pipeline and re-injection. This should not include gas lift.

6. Definitions: Well potential Well Potential = The sum of the individual operating well flow rates tested at optimum operating conditions plus the sum of the third party forecast well potential including gas for fuel, flare and re-injection The optimum operating conditions being the flow potential for a well at the minimum 1st stage separator pressure or the optimum drawdown for good reservoir management (e.g. to prevent water or gas coning and sand free flow). The 1st stage separator pressure being the pressure in the first separator downstream of the well in question. Losses due to mechanical well impairment, localised reservoir restrictions or voidage replacement at the time of the well test will not be captured by the production potential. An “operating well” is defined as a well that is economically viable to operate under the operating conditions of the field. This includes the potential of an operating well that is shut-in for any reason (e.g. workover, annual valve maintenance, reservoir monitoring, etc) If a “non-operating well” is not economic to be brought back onstream and is to be permanently shut-in or abandoned then the well flow potential should be removed from the overall well potential. New well potential should only be included when it is brought onstream.

7. Definitions: Plant potential Plant potential = Sum of the daily throughput potential of the plant  The throughput potential is measured as the quantity of oil, gas, condensate and NGLs that could be processed over a set period of time when no interruptions occur.  Throughput potential should include gas for re-injection, fuel or flare.  The constraint on the throughput can be from any of the following; water, gas, oil processing, flare limits or water disposal limits  Plant potential should not be reduced for planned or unplanned shut-downs  New or modified plant giving additional potential for processing should only be added to the plant potential when brought onstream  The boundary between i. well and ii. plant is at the flange of the wing valve downstream of the christmas tree, so underwater equipment may be part of the plant / host facility rather than the well.

8. Definitions: Export potential Export potential = Maximum volume that can be exported through the pipeline or shuttle tankers (including third party volumes if processed) and re-injection.  Daily sum of the potential export volumes through the export system without any interruptions, planned or unplanned  Re-injection potential (this should not include gas lift)  Includes oil, gas, condensate and NGL potential  Includes any pipeline specification which may limit the export volumes (e.g. maximum % water, H2S PPM, wax content)  Market constraints should not reduce the Export potential.

9. Definitions: Market Potential (gas fields) Market Potential =for some gas fields production is constrained by the type of gas contract that is in place, and this can be the overriding consideration when calculating the SMPP. The monthly volume should be the sum of the daily gas nominations for that month. For the annual shut down when fields are not nominated the number should be zero.  Daily sum of the gas nominations  When reporting an individual field the total annual production should be the production from that field’s reservoir and should not include any substitution or attribution volumes.

10. Well availability or reservoir availability Oil Gas Water Export Total Annual Throughput Production Plant potential Losses recorded against SMPP * *Losses include an “unallocated” category where the reasons for the difference between SMPP and Actual Production have not been determined SMPP Market SMPP is the lowest constraint on production

11. Summary of Field Production Measures Total Annual Throughput is the total processed throughput which is delivered to the export system. It includes third party processing volumes, but excludes “up and over” volumes. Total Annual Production is the total produced and processed volume Total Annual Throughput 3 rd Party Gas 3 rd Party Oil Total Annual Production Wet Gas Evacuated Oil Production Gas Oil

12. Gas Balance GAS PRODUCTION 3 RD PARTY GAS PRODUCTION FLARE GAS FUEL GAS GAS EXPORT GAS RE-INJECTION (not gas lift) GAS THROUGHPUT PRODUCTION FACILITIES

13. Production Constraints – Oil & Gas Fields

14. Production Constraints – Gas fields