Innovations in Reservoir Surveillance DTI Perspective on Reservoir

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

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 2003 - 2010 PILOT targets 2005 & 2010 Source DTI 2003 annual reserves review

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, e. Newsletter •

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

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 • 3 D/4 D 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? Massive sands – un-perforated intervals Existing B 2 perforations Un-perforated Existing B 2 perforations 10383 – 10423 ft md 10423 – 10470 ft md 10478 – 10498 ft md

Innovations in Reservoir Surveillance 2) Existing wells draining effectively?

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

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 – 3 D/4 D, geochem, geomech, Sr. RSA • Permanent surveillance • Difficulty in estimating value – More advanced cost/benefit analysis? •

Innovations in Reservoir Surveillance Andrew production & 4 D surveys Water Rate Maximising Brown field Recovery OIL Rate Baseline 3 D 3 D/4 D Survey acquisition 2001 2002 2004

Innovations in Reservoir 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 UKCS reserves 20 billion boe Key Undeveloped Platform Fields Developed P+P Developed Fields Possible SST P+P SST Possible Undeveloped Probable Undeveloped Possible Potential Additional Subsea tiebacks Source DTI web page 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 •

Innovations in Reservoir Surveillance Thank you for listening For DTI oil & gas information: http: //www. og. dti. gov. uk/ or contact: colin. cranfield@dti. gsi. gov. uk 01224 254066