The Houston Geomechanics Discussion Group is a group of Petroleum Geomechanicists that meets in Houston.

The next meeting will take place at 5:30 PM, Wednesday October 8, 2014 with a presentation entitled "Using Sonic-Density Crossplots in Shales to Distinguish Fluid Expansion as a Pressure Mechanism" by Keith Katahara, Hess Corporation.

The talk will take place in the iCenter located on the ground floor of the Schlumberger building at 1325 S. Dairy Ashford, Houston (NE corner of the intersection between S. Dairy Ashford and Briar Forest Drive) - see Map. Details of the talk are as follows:

Using Sonic-Density Crossplots in Shales to Distinguish Fluid Expansion as a Pressure Mechanism

Keith Katahara, Hess Corporation


In this talk I will discuss patterns in sonic-density crossplots that might arise from different overpressure mechanisms.  In particular, fluid-expansion mechanisms can give distinctly different patterns when clay content is considered as an additional variable.  For this talk, fluid expansion will be defined to be a process in which pore pressure increases with a corresponding decrease or unloading in effective stress.  I will restrict attention to non-source-rock shales, and I will assume that the solid matrix of the shales remains basically unchanged during fluid expansion.  (For overpressure caused by hydrocarbon generation, assume that water-phase overpressure is transmitted into the shale from a neighboring source formation, such as a coal, but that hydrocarbons do not enter the shales.)  I will discuss examples from the North Malay Basin and the Gulf of Mexico.

Speaker Biography

Keith Katahara is a Sr. Geophysical Advisor at Hess Corporation.  He earned a Ph.D. in geophysics from the University of Hawaii and then spent a few years on the research faculty there.  His industry experience before Hess includes stints at ARCO-Vastar-BP, at Spinnaker-Hydro-Statoil and at Devon.  He is interested in rock physics, quantitative seismic analysis, pore-pressure estimation, and related aspects of geomechanics.