Text Size
Print Page
Print This Page
E-mail Page
Email This Page

Rock Physics Studies

Studying rock properties is very important to the geoscientist as it draws a relationship between well logs and seismic and acts as a forward-modeling and calibration tool. As a result of rock property studies, rock and fluid constituents as well as porosity can be arbitrarily varied and subsequently forward modeled. This allows an interpreter to calibrate seismic attributes at well locations to known reservoir parameters and then to estimate reservoir parameters at potential exploration sites.

Rock Study Specialists

Our experts have extensive experience in the complex process of regional rock physics studies involving log processing, rock physics modeling, and seismic modeling and verification. These studies require a systematic approach to editing, verifying, and reconciling diverse data types. Because the rock physics effort is log-based, we assemble available logs suites into a common database and pay close attention to the Vp, Vs and density curves. If appropriate, we can depth-shift the seismic rock properties to bring them into alignment for improved synthetic generation.

Shear velocity plays a vital role in AVO analysis and modeling, however, this key component it is often missing or has impaired values. Using available shear logs as calibration, we test a variety of shear estimation techniques against good-quality data to develop a method for estimating shear velocity in the missing areas. Using seismic rock properties, we perform an important rock physics interpretation step called Velocity Diagnosis in Vp (and Vs) vs. Porosity space to characterize not only the role of diagenesis, but also porosity and clay content in potential reservoir sands.

Once a rock physics model(s) has been selected, the third and crucial step consists of forward modeling each of the seismic rock properties over a range of porosity, clay content, and hydrocarbon type. Often, available logs do not encompass the full range of possible rock properties likely to be encountered in a regional survey. We generate a complete set of tables of Vp, Vs and density vs. porosity, clay content, and hydrocarbon type. In addition, we create rock properties for brine saturated sands. As a valuable interpretation aid for future direct hydrocarbon detection endeavors, we also produce a catalog of AVO signatures. Finally, we create seismic attribute and seismic rock property cross-plots to determine those attributes capable of distinguishing hydrocarbon from brine filled sand. Understanding these relationships leads to a better estimate of hydrocarbon content within a rock layer. The ultimate objective is to develop a deep understanding of the rock and fluid models that describe the seismic response to realistic hydrocarbon reservoirs under a variety of conditions.