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……

QUESTIONS?