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EAGE Conference & Exhibition incorporating SPE EUROPEC 2011Vienna, Austria, 23-26 May 2011

P274

Stochastic 3D Carbonates Modelling to SupportDrilling and Production Forecasts in the Gulf ofMexico, Cantarell Asset

H Marquez* (Roxar Software Solutions), S. Esteban (Pemex E&P), G.Martn (Pemex E&P) & P. Hernando (Roxar Software Solutions)

SUMMARY

The Kutz offshore field, within PEMEXs Gulf of Mexico Cantarell Asset, has a symmetrical anticlinalwith a considerable level of heterogeneity as result of a combination of geological events. The availabledata for this study includes lithology and petrophysical well logs, 3D seismic, core analysis, and

production history for both Eocene-Paleocene and Upper, Middle and Lower Cretaceous reservoirs. Thispaper examines how stochastic 3D carbonate models were created to support drilling and production

forecasts in the Kutz field. The result is the first full-field geostatistical and detailed model from the fieldto honour reservoir heterogeneity. It will be used to simulate the further development of the field and tomaximise oil recovery through water, gas, CO2 and Nitrogen injection processes.

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Introduction

The Kutz offshore field, within PEMEXs Gulf of Mexico Cantarell Asset, is located in the Marine

Region, Campeche State, next to the giant Akal field in the Gulf of Mexico (see figure 1). The field

has a symmetrical anticlinal with a considerable level of heterogeneity as result of a combination of

geological events, including complex compressional faulting and a diversity of sedimentary

environments linked to the generation of carbonates and severe transportation processes.

Figure 1 The Kutz Offshore Field

The available data for this study includes lithology and petrophysical well logs, 3D seismic, core

analysis, and production history for both Eocene-Paleocene and Upper, Middle and Lower Cretaceous

reservoirs. This available data and the structural seismic interpretation and depth conversion

information are found in figure 2.

Figure 2 Structural Seismic Interpretation and Depth Conversion based on 12 Wells

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EAGE Conference & Exhibition incorporating SPE EUROPEC 2011Vienna, Austria, 23-26 May 2011

This paper examines how stochastic 3D carbonate models were created to support drilling and

production forecasts in the Kutz field.

Building The Model

A high resolution modelling grid of 13 millions cells was built using corner-point geometry and

incorporating 10 faults. Reservoir properties were distributed using stochastic 3D modelling for both

facies and petrophysics (see figure 3).

Figure 3

The Eocene and Paleocene Turbidite reservoirs (see figure 4) were modelled through object-based

modelling.

Figure 4

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EAGE Conference & Exhibition incorporating SPE EUROPEC 2011Vienna, Austria, 23-26 May 2011

The Cretaceous reservoir (figure 5) was modelled using a combination of object and pixel-based

methods (Sequential Indicator Simulation) conditioned to 3D seismic attributes. The resultingrealizations reproduced the conceptual sedimentological model.

Figure 5

For petrophysical modelling, the Sequential Gaussian Simulation algorithm with trends was used formodelling effective porosity, permeability and rock types for the first and second medium, as

illustrated in figure 6.

Figure 6

A simulation of the discrete fracture network was also built to reproduce the natural fractures in 3D

and for estimating the modified permeability, both conditioned to seismic attributes and based on the

variograms and geomechanical analysis.

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EAGE Conference & Exhibition incorporating SPE EUROPEC 2011Vienna, Austria, 23-26 May 2011

Uncertainty and Probability Analysis

Finally, 50 realizations were produced for uncertainty and probability analysis, including recovery

factor estimation. Three realizations (P10, P50 and P90) were re-scaled in order to start the

compositional simulation stage. After flow simulation, the one with the best match to historical data

was selected as the most representative. Figure 8 outlines this process.

Figure 7

Conclusions

The result is the first full-field geostatistical and detailed model from the field to honour reservoir

heterogeneity. It will be used to simulate the further development of the field and to maximise oil

recovery through water, gas, CO2 and Nitrogen injection processes.