Capillary Pressure: Theory, Measurements, and Applications
Date: Monday May 19, 2014
Time: 8:00 AM – 5:00 PM
Place: Capital Suite – ADNEC
Instructors: Joe Comisky, Apache Corporation, Houston, TX; Paul Connolly, EOG Resources, Houston, TX
Capillary pressures within the pores of rocks fundamentally control the distribution and flow of fluids in the subsurface. This class will introduce the measurement and use of capillary pressures for characterizing the pore throat and fluid distributions within both reservoirs and seals. We will introduce the basic concepts of adhesion and interfacial tension, contact angle, and density contrast between reservoir fluid phases and show how these relate to the generation of capillary pressures in the subsurface. The key concept of relating these rock-fluid properties to a pore throat radius distribution will be central in tying capillary pressures back to other commonly measured petrophysical properties including porosity and permeability. Several different methods are available in the laboratory for measuring capillary pressure and pore throat distributions; many of which will be covered in detail here including the advantages and drawbacks of each. Techniques such as mercury injection will be emphasized since it is also a powerful tool for determining the porosity, permeability, and bulk/grain densities of small samples such as cuttings. Finally we will use both synthetic and real world examples to illustrate how the concept of capillary pressure is integrated with information gathered from wellbore measurements. This course requires a prior understanding of basic well log measurements and petrophysical properties of rocks.