Carbonate Reservoir Characterization

Frontmatter

Chapter 1. Petrophysical Rock Properties

Abstract

The principal goal of reservoir characterization is to construct three- and fourdimensional images of petrophysical properties. The purpose of this chapter is to review basic definitions and laboratory measurements of the petrophysical properties porosity, permeability, relative permeability, capillarity, and saturation. Pore-size distribution is presented as the common link between these properties.

F. Jerry Lucia

Chapter 2. Rock-Fabric, Petrophysical Parameters, and Classification

Abstract

The goal of reservoir characterization is to describe the spatial distribution of petrophysical parameters such as porosity, permeability, and saturation. Wireline logs, core analyses, production data, pressure buildups, and tracer tests provide quantitative measurements of petrophysical parameters in the vicinity of the wellbore. This wellbore data must be integrated with a geologic model to display the petrophysical properties in three-dimensional space. Studies that relate rock fabric to pore-size distribution, and thus to petrophysical properties, are key to quantification of geologic models in numerical terms for input into computer simulators (Fig. 1).

F. Jerry Lucia

Chapter 3. Rock-Fabric/Petrophysical Properties from Core Description and Wireline Logs: The One-Dimensional Approach

Abstract

Petrophysical measurements and rock-fabric descriptions provide a basis for quantifying geological descriptions with petrophysical properties but represent point data. Point data are expanded in one dimension by detailed sampling of core material, and the vertical sequence of rock fabrics is used to extrapolate the petrophysical data laterally, as will be discussed in a later chapter. Core samples are normally available from only a few wells, whereas wireline logs are available from most wells. Therefore, most geological as well as petrophysical information must be derived from wireline logs.

F. Jerry Lucia

Chapter 4. Origin and Distribution of Depositional Textures and Petrophysical Properties: The Three-Dimensional Approach

Abstract

Petrophysical properties can best be distributed in the interwell space if constrained by a chronostratigraphic framework.

F. Jerry Lucia

Chapter 5. Diagenetic Overprinting and Rock Fabric Distribution: The Cementation, Compaction, and Selective Dissolution Environment

Abstract

The three-dimensional spatial distribution of petrophysical properties is controlled by the spatial distribution of geologic processes, processes that can be separated into depositional and diagenetic. In Chapter 4 we discussed depositional processes and focused on (1) the origin of depositional textures, (2) the relationship between porosity, permeability, and depositional texture, (3) the vertical and lateral distribution of depositional textures related to topography, current energy, biologic activity, and eustatical controlled cyclicity, and (4) the fundamentals of sequence stratigraphy. The importance of chronostratigraphic surfaces was emphasized as the fundamental element in constructing a geological framework within which petrophysically-significant depositional textures can be systematically distributed.

F. Jerry Lucia

Chapter 6. Diagenetic Overprinting and Rock-Fabric Distribution: The Dolomitization/Evaporite-Mineralization Environment

Abstract

In Chapter 5 we stated the basic premise that the three-dimensional spatial distribution of petrophysical properties is controlled by the spatial distribution of geological processes, processes that can be separated into depositional and diagenetic. In Chapter 4 we discussed depositional processes and the relationship between the spatial distribution of depositional textures and petrophysical properties. Reservoir studies have made it abundantly clear that the petrophysical properties found in carbonate reservoirs are significantly different from those of Holocene carbonate sediments due to various diagenetic processes.

F. Jerry Lucia

Chapter 7. Diagenetic Overprinting and Rock-Fabric Distribution: The Massive Dissolution, Collapse, and Fracturing Environment

Abstract

A key question in mapping diagenetic effects is the degree of conformance between diagenetic products and depositional patterns. As discussed in Chapter 5, the products of cementation, compaction, and selective dissolution can normally be linked to depositional textures because the transport of material in and out of the system is not an important factor in producing the diagenetic product. However, if the transport of ions in and out of the system by fluid flow is required to produce the diagenetic product, then the product may not conform to depositional patterns. In this case, knowledge of the geochemical, hydrological system may be required to map the diagenetic products, including the source of the fluid and the direction of fluid flow.

F. Jerry Lucia

Chapter 8. Reservoir Models for Input into Flow Simulators

Abstract

Reservoir characterization is defined as the construction of realistic three-dimensional images of petrophysical properties to be used to predict reservoir performance. A key element in constructing reservoir models is modeling the high and low permeabilities. In the past, these images have been prepared by several different methods including (1) the layered reservoir method, (2) the continuous pay method, and (3) the facies method (Fig. 1). In the layered reservoir method, the reservoir is divided into pay zones using correlations based on gamma ray logs, and the net feet of porosity (net pay maps) or the porositytimes-oil-saturation (SoPhiH maps) isopached for each layer. The layers commonly lump several petrophysical rock types, and the average petrophysical values do not characterize the flow properties of the reservoir.

F. Jerry Lucia

Erratum to: Petrophysical Rock Properties

F. Jerry Lucia

Errata

F. Jerry Lucia

Backmatter