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Forgotten Oil & Gas Study. 2013 User Conference Hosted by Maersk – Houston November 14, 2013. John D. Grace Earth Science Associates Long Beach, CA. Goals. High-grade opportunities for new production from “dead” reservoirs Develop methods for mass-batch decline curve analysis
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Forgotten Oil & Gas Study 2013 User Conference Hosted by Maersk – Houston November 14, 2013 John D. Grace Earth Science Associates Long Beach, CA
Goals • High-grade opportunities for new production from “dead” reservoirs • Develop methods for mass-batch decline curve analysis • Identify “non-balancing” movements in field & sand reserve estimates • Demonstrate “data mining” approach to analysis using GOM3
Decline Curve Study Last Production Date Production Production Rate Estimated Remaining Recoverable Volume Statistically Estimated Decline Rate Estimated Current Abandonment Rate Number of Months On
Total Volumes & Uncertainty 12 9 6 3 500 400 300 200 100 0 0 Gas (Tcf) Oil (Million Bbls) Both oil and gas scaled in BOE
Size/Frequency Reservoir Recoverable Volume 4 1,500 3 1,000 Freq. 2 Freq. (x 1,000) 500 1 0 0 0 10 20 M Bbls 3 MM Bbls 500 0 10 20 MMCF 95 BCF 3 BCF 500 Bbls MCF
Largest Reservoirs Found 12 40 10 30 8 Reservoirs 20 6 4 10 2 0 0 6 20 30 40 50 60 70 10 1 2 3 4 5 Remaining Oil (Million Bbls) Remaining Gas (Bcf)
Cost Proxies Dot Size Proportional to Remaining BOE
Decline Methodology • Studied reservoirs “dead” at end 2009 • Applied GOM3 Decline Curve Tool in batch • Process data to find final “regime break” • Apply 4 standard engineering models • Corrected bias in exponential estimates • Retained confidence intervals for estimates • Picked best model with R2 (R2 0.6) • Determined “current” abandonment rate
Break in Structural Regime Global Prod. Max Break in Regime Regime Estimated
Standard Decline Models • Exponential rate v time: • Linear rate v cumulative prod: • Hyperbolic rate v time: • If exponential; harmonic; hyperbolic
Models Tried: Picked Best Above Threshold This reservoir does not pass the R2>0.6 criteria
Example: WC49 Field: L04 Sand L04 Sand 371 MMcf Remaining L-8 & L-4NM reservoirs (12,919-13,134) Very low & strange production A and PA-3 reservoirs (13,406-14,308). Comps produced 27 & 28 bcf respectively ? 6 Bcf Remaining
Found in Reserve Histories Fields Sands 6 BBL 5 BBL 4 BBL 3.6 BBL 17 TCF 32 TCF 18 TCF 34 TCF
Next steps • Get input from these presentations • Complete analysis of Reserve Histories • Final revisions to numbers & software • Produce deliverables • Decide on marketing strategy