SPE 153275-PPA 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 153275-PP A Method for Probabilistic Forecasting of Oil Rates in Naturally Fractured Reservoirs
Presenter: Julio Muñoz Blanco
OUTLINE
1. FLOWCHART ANALYSIS2. THEORETICAL FRAMEWORK3. RESERVOIR DESCRIPTION AND PROPERTIES4. PROBABILISTIC OIL RATES DETERMINATION5. INTEGRATION METHODOLOGY FOR CRITICAL RATES6. NODAL ANALYSIS MATCH7. CONCLUSIONS
SPE 153275-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 153275-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 153275-PP A Method for Probabilistic Forecasting of Oil Rates in Naturally Fractured Reservoirs
Presenter: Julio Muñoz Blanco
Reservoir Description and Properties
INITIAL PRESSURE: 9960 psiaTEMPERATURE: 307 °FDATUM: 17700 feetOIL GRAVITY: 38 °APISTOOIP: 3800 stbo
PRODUCTION MECHANISM:• ROCK AND FLUID EXPANSION• AQUIFER • SOLUTION GAS DRIVE• COUNTER FLOW GRAVITY
SEGREGATION• PRESSURE MAINTENANCE
SPE 153275-PP A Method for Probabilistic Forecasting of Oil Rates in Naturally Fractured Reservoirs
Presenter: Julio Muñoz Blanco
Variable Distribution Graph
Static Pressure Log Normal
Bottom Hole Pressure Log Normal
Fracture Permeability Log Normal
Matrix Permeability Log Normal
Fracture Density Log Normal
Perforated Interval Log Normal
Oil Viscosity Triangular
Oil Form. Vol. Factor (Bo) Triangular
Skin Factor Log Normal
Probabilistic Oil Rates Determination
SPE 153275-PP A Method for Probabilistic Forecasting of Oil Rates in Naturally Fractured Reservoirs
Presenter: Julio Muñoz Blanco
Integration Methodology for Critical Rates
Static and DynamicReservoir Behavior
Static and DynamicReservoir Behavior
Determine Variable Distribution
Estimate Probabilistic Rates Estimate Critical Rates
Estimate Average Rate by Well, Area or Field
Generate Initial Rate Variation Range
1
1 2
2
1. PLT Logs2. Perforated Intervals3. Fluids Gradients4. Fracture Width5. Layers Dip6. Turbulence Radius
1. Static Pressures2. Flowing Pressures3. Permeability4. Perforated Intervals5. Skin Factor6. Fracture Density
Current anf Future Fluid Levels by Well
Validate Rate with Nodal Analysis
SPE 153275-PP A Method for Probabilistic Forecasting of Oil Rates in Naturally Fractured Reservoirs
Presenter: Julio Muñoz Blanco
Analysis Nodal Match
Oil Initial Rate, bd
Range Percentile Zone 1 Zone 2 Zone 3
Low 10% 702 980 712
Medium 50% 1500 2167 1700
High 90% 3775 5188 4275
Nodal Oil Rates, bd
Well Description P10 P50 P90Qo mín. Qo máx. Qo mín. Qo máx. Qo mín. Qo máx.
CP-1 Rate 690 750 2100 2300 5000 5200Angle 0° 20° 0° 20° 0° 20°
CP-2 Rate 2000 2100 3550 3850 5750 6250Angle 0° 32° 0° 32° 0° 32°
CP-3 Rate 1100 1200 1650 1700 3700 4000Angle 0° 20° 0° 20° 0° 20°
SPE 153275-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 153275-PP A Method for Probabilistic Forecasting of Oil Rates in Naturally Fractured Reservoirs
Presenter: Julio Muñoz Blanco
THANKS……
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