Rock Typing as an Effective Tool for Permeability and Water-Saturation Modeling: A Case Study in a Clastic Reservoir in the Oriente Basin

Guo, Genliang; Díaz, Marlon; Paz, Francisco Jose; Smalley, Joe; Waninger, Eric

doi:10.2118/97033-ms

Cited by 44 publications

(12 citation statements)

References 13 publications

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“…Rock type relationships range from simple to complex, concerning depositional facies (Gomes et al 2008); however, it is possible to illustrate well-defined relationships between porosity and permeability when conventional core data are grouped following rock type discrimination (Guo et al 2007;Willhite 1986). The relationship between petrophysical properties also exists with the coincident relative permeability and capillary pressure descriptions for construed rock type relationships identified by Guo et al (2007). The suggestion here is that a similitude in relationship between petrophysical and hydraulic conductivity could exist between analogous rock types, although the depositional or geologic description can vary between the respective rock types.…”

Section: Theory and Definitionsmentioning

confidence: 99%

Petrofacies Determination in Unconventional Reservoirs Driven by a Simulation-to-Seismic Process

Ramsay

Yarus

2015

Europec 2015

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It is well-understood that hydraulic rock types categorize flow unit regimes in porous media such that modeling of these regimes according to hydraulic conductivity is possible in a reservoir simulator. This hydraulic characterization is necessary in reservoir simulation to spatially dictate multiphase flow behavior throughout the modeled reservoir. The spatial delineation of these multiphase data then relies on a singular relationship between petrophysical properties, which can be used to assign the multiphase properties to the simulation grid; the properties and requisite relationship of choice are between absolute permeability and porosity.This paper illustrates that a simulation-to-seismic modeling approach can be used to reconcile large-scale flow disparities in the dynamic reservoir model, resultant of diminished spatial constraints during the creation of the static petrophysical model with seismic attribute array data. The results demonstrate that the assignment of multiphase hydraulic descriptions to petrofacies have considerable control on simulated rates and produced volumes. The examination of selected simulation scenarios leads to the conclusion that petrofacies, when derived considering petrophysical cutoffs and hydraulic rock types, provide an alternative to incorporating depositional facies constraints during the modeling of select shale reservoirs, wherein the understanding of a regionalized modeling constraint is limited. Additionally, it is shown that geologic facies are not flow units while they are considered regionalized variables. The uncertainty associated with unconstrained petrofacies is then recognized as broad; but, it is accepted that this modeled petrophysical system allows for the described petrofacies to be used as a proxy for hydraulic conductivity in the absence of a facies-based spatial constraint.A novel approach is introduced in this work to construct petrofacies from log curves and core data to relate hydraulic rock types and petrophysical properties to the simulation grid using a methodology that honors the available seismic. The mathematical formulation used to describe petrofacies can be modest or elaborate; however, they differ from geologic facies, which can be described as regionalized variables. Unlike geologic facies, petrofacies do not adhere to interpretable geometries and thus might not be considered as regionalized variables or functionally modeled with deterministic or stochastic algorithms.

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Section: Theory and Definitionsmentioning

confidence: 99%

Petrofacies Determination in Unconventional Reservoirs Driven by a Simulation-to-Seismic Process

Ramsay

Yarus

2015

Europec 2015

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“…If the functions are not suitable for a reservoir, it will lead to inaccurate approximations during the process of the numerical simulation history matching for a field (Obinna et al 2010;Joseph et al 2012). Because of the wide range of lateral variations of the physical properties, carbonate reservoirs often have poor or no porosity/permeability correlation which will increase the complication in building capillary pressure models for non-cored wells (Buiting and Aramco 2011;Guo et al 2007;Ibrahim 2009). …”

Section: Introductionmentioning

confidence: 99%

Saturation modeling in a carbonate reservoir using capillary pressure based saturation height function: a case study of the Svk reservoir in the Y Field

Lian

Tan

et al. 2015

J Petrol Explor Prod Technol

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Because of the complex pore structure and the strong heterogeneity of the Svk carbonate reservoir in the Y Field, water saturation distribution and petrophysical properties, such as porosity, permeability and capillary pressure are difficult to be characterized. To solve this problem, a new method to interpret water saturation was presented. By this method, the relationships among porosity, permeability and different pore throat radii are fitted and a typical radius R30 (the pore aperture radius corresponding to 30 % of mercury saturation in a mercury penetration test) selected. By fitting the capillary pressure curves with Corey-Brooks function, the threshold pressure, the irreducible water saturation and the Corey exponent ''n'' of each capillary pressure curve can be determined, and the relationship between R30 and the threshold pressure, R30 and the irreducible water saturation, and R30 and the Corey exponent can all be fitted. If the R30 value is known, the threshold pressure, irreducible water saturation and Corey exponent can be calculated by the fitting equations; hence, the water saturation at a given height from FWL can be calculated by the Corey-Brooks function. The water saturation calculated by saturation height function is consistent with that of the well log interpretation and the error is less than by other methods. During the process of three-dimensional saturation modeling, an R30 criterion is presented to define rock types, six petrophysical rock types with different reservoir properties are distinguished and a link is set up between rock types and log responses by the KNN method. Logs are utilized to predict rock types of non-cored wells according to this link, and a three-dimensional rock-type model is established by the Petrel software. R30 value of each grid can be calculated by R30 formula when three-dimensional porosity and permeability models are built with the restraint of rock-type model. Then, on the basis of the saturation height function, a threedimensional water saturation model can be obtained.

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“…(Davies et al, 1996;Guo et al, 2005;Shenawi et al, 2007) It has many applications in reservoir characterization and simulation studies.…”

Section: Introductionmentioning

confidence: 99%

Field Application of a Modified Kozeny-Carmen Correlation to Characterize Hydraulic Flow Units

et al. 2011

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractHydraulic Flow Unit (HU) has been used extensively as a technique in permeability modeling and rock typing. Amaefule et al. (1993) introduced for the first time the concept of Reservoir Quality Index (RQI) and Flow Zone Indicator (FZI) by using the Kozeny-Carmen (K-C) model to characterize HU and predict permeability in uncored wells and intervals.This technique has helped in enhancing the capability to capture the various reservoir flow behavior based on its respective characters. Yet, there are challenges in using the original correlation due to its inherent limitations and over simplified assumptions that prevent accurate HU definitions. This study highlights some of those shortcomings and proposes a modified K-C correlation that enhances the HU characterization.It is found that the conventional K-C model ignores the inherent nonlinear behavior between the tortuosity and porosity. Hence, handling the tortuosity term in a more representative manner demonstrates a more rigorous correlation that extends the applicability of this powerful technique into more heterogeneous rocks -such as those found in carbonate reservoirs. This paper presents a reservoir simulation case study that is conducted to validate the applicability of the proposed model as a rock typing technique in a heterogeneous carbonate reservoir in the Middle East region. Relative permeability curves, Leverett J-Function curves and initial water saturation distribution show good agreement within each HU generated using the proposed model.It is recognized that modified Kozeny-Carmen technique give better matching of initial water saturation model than the conventional technique when compared to open-hole logs which, in turn; adds confidence to initial hydrocarbon-in-place calculations and reservoir behavior predictions. This result will ultimately enhance the prediction of reservoir performance under various scenarios in reservoir simulation.

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Rock Typing as an Effective Tool for Permeability and Water-Saturation Modeling: A Case Study in a Clastic Reservoir in the Oriente Basin

Cited by 44 publications

References 13 publications

Petrofacies Determination in Unconventional Reservoirs Driven by a Simulation-to-Seismic Process

Petrofacies Determination in Unconventional Reservoirs Driven by a Simulation-to-Seismic Process

Saturation modeling in a carbonate reservoir using capillary pressure based saturation height function: a case study of the Svk reservoir in the Y Field

Field Application of a Modified Kozeny-Carmen Correlation to Characterize Hydraulic Flow Units

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