Innovations in Reservoir Surveillance DTI Perspective on Reservoir Surveillance Colin Cranfield Reservoir Engineer Licensing and Consents Unit Aberdeen 15 September 2004

Innovations in Reservoir Surveillance Quote from the late Laurie Dake* Thorough data acquisition is expensive (very expensive) and it is the duty of practising reservoir engineers to convince those who hold the purse strings of the necessity of the exercise. * “The Practice of Reservoir Engineering”

Innovations in Reservoir Surveillance Overview DTI-LCU remit –PILOT initiatives UKCS reserves –Brown field growth Reservoir surveillance –General issues –Field observations Conclusions

Innovations in Reservoir Surveillance DTI-LCU aim Maximise economic recovery of UK oil & gas –while minimising environmental impact

Innovations in Reservoir Surveillance Reservoir surveillance is important throughout field life Need to establish economic viability of reservoir,.e.g EWTs Gain reservoir understanding for effective management Establish that reservoir is uneconomic prior to abandonment Field determination issued FDP approved Field start-up COP AFRs submitted / Addenda to FDP Pre-development discussions Phased development ?

Innovations in Reservoir Surveillance PILOT targets Government – industry partnership –Striving to meet 2010 target

Innovations in Reservoir Surveillance PILOT targets Government – industry partnership –Striving to meet 2010 target Can only be achieved via –New field development –Brown field growth –Exploration success

Innovations in Reservoir Surveillance UK production forecast (mmboe/d) Actual production Forecast UKCS oil and gas production Source DTI 2003 annual reserves review PILOT targets 2005 & 2010

Innovations in Reservoir Surveillance DTI initiatives PILOT –Fallow process –Promote licences –Access to data –Infrastructure code of practice –Brown field work group Plus –Work with ITF on technology development –IOR conferences, web sites, eNewsletter

Innovations in Reservoir Surveillance UKCS recovery factor distribution Northern North Sea Oil Recovery 43% (upside 45%) Southern North Sea Gas Recovery 74% (upside 78%) - Source DTI Central North Sea Oil Recovery 46% (upside 49%) Gas Recovery 65% (upside 71%) Key Oil Gas Production to date P+P Reserves Possible reserves Unrecovered

Innovations in Reservoir Surveillance Improving brown field recovery Source UK Oil & Gas Commemorative Volumes

Innovations in Reservoir Surveillance Brown field growth Brown field WG addressing barriers Typical success factors –Cost control –Combining technologies Technological advances Drilling & completion –Geo-steering Sub-sea tie-back Improved reservoir understanding Integrated approach 3D/4D advances

Innovations in Reservoir Surveillance By-passed & trapped oil Causes –Reservoir compartmentalisation –Fault shadows –Heterogeneity –Attics Opportunities –Better utilise injection –Infill / sidetrack locations –Well work / re-perforation / water or gas shut-off

Innovations in Reservoir Surveillance 1) Existing wells draining effectively?

Innovations in Reservoir Surveillance 1) Existing wells draining effectively? Existing B2 perforations – ft md Un-perforated10423 – ft md Existing B2 perforations – ft md Massive sands – un-perforated intervals

Innovations in Reservoir Surveillance 2) Existing wells draining effectively?

Innovations in Reservoir Surveillance 2) Existing wells draining effectively? Un-perforated interval 11,770 – 11,790 ft md Channel sands – un-perforated interval

Innovations in Reservoir Surveillance 3) Existing wells draining effectively? Gamma ray spikes – could they be horizontal barriers?

Innovations in Reservoir Surveillance Typical surveillance approaches Routine –RFT, LWD, logging –Production performance Non-routine –3D/4D, geochem, geomech, SrRSA Permanent surveillance Difficulty in estimating value –More advanced cost/benefit analysis?

Innovations in Reservoir Surveillance Andrew production & 4D surveys Baseline 3D D/4D Survey acquisition Maximising Brown field Recovery OIL Rate Water Rate

Innovations in Reservoir Surveillance Surveillance challenges – past and present Compartmentalisation –Impacted injection strategies Hydraulic fracturing –Poorly controlled water injection Marginal / sub-sea developments –Pre-drilled wells Based on static data Non-optimum well placement –Defer injection wells? Inaccurate zonal allocation –Inability to model reservoir

Innovations in Reservoir Surveillance UKCS reserves categorised by development type Source DTI web page Platform Fields Subsea tiebacks Undeveloped UKCS reserves 20 billion boe Key Developed P+P Developed Fields Possible SST P+P SST Possible Undeveloped Probable Undeveloped Possible Potential Additional FPFs/FPSOs

Innovations in Reservoir Surveillance Way forward - reservoir surveillance Continue to refine and improve surveillance –Down-hole flow- & pressure-meters By zone Continue to integrate data observations –More sophisticated analysis Tailor strategy to specific reservoir situation –Address key uncertainties Develop case for thorough data acquisition

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