SPE PP A Method for Probabilistic Forecasting of Oil Rates in Naturally Fractured Reservoirs Julio César Muñoz Blanco y Rafael Paz Palenzuela, CBM Ingeniería, Exploración y Producción; Roberto Aguilera, SPE- Schulich School of Engineering / University of Calgary

SPE PP A Method for Probabilistic Forecasting of Oil Rates in Naturally Fractured Reservoirs Presenter: Julio Muñoz Blanco OUTLINE 1.FLOWCHART ANALYSIS 2.THEORETICAL FRAMEWORK 3.RESERVOIR DESCRIPTION AND PROPERTIES 4.PROBABILISTIC OIL RATES DETERMINATION 5.INTEGRATION METHODOLOGY FOR CRITICAL RATES 6.NODAL ANALYSIS MATCH 7.CONCLUSIONS

SPE PP A Method for Probabilistic Forecasting of Oil Rates in Naturally Fractured Reservoirs Presenter: Julio Muñoz Blanco Probabilistic Determination of Wells Initial Oil Rate by Area Validation of Probabilistic Well Initial Rate with Nodal Analysis Production Forecasts From Probabilistic Well Initial Rates Generation of Production Forecasts with Reservoir Simulation Model Integration of Production Forecasts with Scenarios Integrated Evaluation Model Methodology that integrates the determination of probabilistic well initial rate with critical rates and integrated reservoir management concepts Determination and validation of the wells production capacity including sensitivities to deviation angle of drilling trajectory Estimates and validation of production forecasts by well from probabilistic (maximum, most likely and minimum) well initial rates Production forecasts with random variation of wells initial rate. Estimate of probabilistic range for field production rate (P10, P50, P90) Integration of production forecast model with investment, cost and economical models Analysis Flowchart

SPE PP A Method for Probabilistic Forecasting of Oil Rates in Naturally Fractured Reservoirs Presenter: Julio Muñoz Blanco Theoretical Framework DARCY EQUATION NFRs ROCK PROPERTIES PARTITIONING COEFFICIENT MODIFIED DARCY EQUATION

SPE PP A Method for Probabilistic Forecasting of Oil Rates in Naturally Fractured Reservoirs Presenter: Julio Muñoz Blanco Reservoir Description and Properties INITIAL PRESSURE: 9960 psia TEMPERATURE: 307 °F DATUM: feet OIL GRAVITY: 38 °API STOOIP: 3800 stbo PRODUCTION MECHANISM: ROCK AND FLUID EXPANSION AQUIFER SOLUTION GAS DRIVE COUNTER FLOW GRAVITY SEGREGATION PRESSURE MAINTENANCE

SPE PP A Method for Probabilistic Forecasting of Oil Rates in Naturally Fractured Reservoirs Presenter: Julio Muñoz Blanco Probabilistic Oil Rates Determination

SPE PP A Method for Probabilistic Forecasting of Oil Rates in Naturally Fractured Reservoirs Presenter: Julio Muñoz Blanco Integration Methodology for Critical Rates Static and Dynamic Reservoir Behavior Static and Dynamic Reservoir Behavior Determine Variable Distribution Estimate Probabilistic Rates Estimate Critical Rates Estimate Average Rate by Well, Area or Field Generate Initial Rate Variation Range PLT Logs 2.Perforated Intervals 3.Fluids Gradients 4.Fracture Width 5.Layers Dip 6.Turbulence Radius 1.Static Pressures 2.Flowing Pressures 3.Permeability 4.Perforated Intervals 5.Skin Factor 6.Fracture Density Current anf Future Fluid Levels by Well Validate Rate with Nodal Analysis

SPE PP A Method for Probabilistic Forecasting of Oil Rates in Naturally Fractured Reservoirs Presenter: Julio Muñoz Blanco Analysis Nodal Match Oil Initial Rate, bd RangePercentileZone 1Zone 2Zone 3 Low10% Medium50% High90% Nodal Oil Rates, bd WellDescription P10P50P90 Qo mín.Qo máx.Qo mín.Qo máx.Qo mín.Qo máx. CP-1 Rate Angle0°20°0°20°0°20° CP-2 Rate Angle0°32°0°32°0°32° CP-3 Rate Angle0°20°0°20°0°20°

SPE PP A Method for Probabilistic Forecasting of Oil Rates in Naturally Fractured Reservoirs Presenter: Julio Muñoz Blanco Conclusions 1. An easy to use modified Darcy equation has been presented for statistical determination of oil rates in naturally fractured reservoirs. The equation incorporates variables such as matrix and fracture permeabilities and the partitioning coefficient. The use of mathematical algorithms or dependence of variables involved in the equation allows the estimation of more reliable initial oil rates. 2. A methodology that integrates the statistical and critical oil rates with a view to reduce premature gas and water coning has been developed. 3. The complex heterogeneous reservoir considered in this study results in different pressures and different gas-oil and water-oil levels, which vary significantly depending on the exploitation stage. This can be handled quickly, easily and with a good level of accuracy for different areas of the reservoir using the proposed methodology. The methodology, however, is not meant to replace more detailed reservoir simulation and probabilistic studies. 4. The proposed methodology can be used for other reservoirs depending on the exploitation stage. This might require handling of different technical uncertainties.

SPE PP A Method for Probabilistic Forecasting of Oil Rates in Naturally Fractured Reservoirs Presenter: Julio Muñoz Blanco THANKS…… QUESTIONS?