TABLE OF CONTENTS Giga Scale information helps define reservoir architecture, but is too coarse to provide the detail needed to characterize the reservoir enough to design a reservoir management plan. The Mega Scale is the scale at which we begin to integrate well log and pressure transient test data into a working model of the reservoir. This chapter introduces the role of well log and pressure transient test data in reservoir modeling. We then discuss the concept of flow unit.
Well logs provide valuable information about the formation within a few feet of the wellbore. A thorough discussion of well logging is beyond the scope of this book. We describe several concepts that are applicable to reservoir modeling. For more information, the interested reader should consult references such as Brock [1986], Bassiouni [1994], and Asquith and Krygowski [2004].
Well logs are obtained by running a tool into the wellbore. The tool can detect physical properties such as temperature, electrical current, radioactivity, or sonic reflections. Logging tools are designed to function best in certain types of environments. The environment depends on a variety of factors, including temperature, lithology, and fluid content. The theoretical analysis of log signals is usually based on the assumption that the formation is infinite in extent with homogeneous and isotropic properties. Tool performance will not be optimal in other environments.
Table 13-1 illustrates the type of information that can be obtained at the Mega Scale level from well log data. The most common interpretations of each...
