Print this pageDetailed Pore Geometry Description Using Core Porosity, Core Permeability, and Mercury Injection Capillary Pressure Data, Norte de Monagas Area, Eastern Venezuela
PORRAS, JUAN CARLOS
The Norte de Monagas area is located in the Eastern Venezuelan Basin and is characterized by high temperature, high initial pressure and production rates, Production rates are associated to grain and pore type, with pore throat being the dominant control on permeability and the flow characteristics of the reservoirs.
Mercury injection capillary pressure data provided useful information about effective pore throat radius. Pore throat radii were semi-quantitatively related to several reservoir responses, such as permeability, porosity, irreducible water saturation, and a capillary pressure profile or pore throat type curve.
Mercury saturation versus mercury saturation over capillary pressure plots show that the dominant interconnected pore system which controls flow rates is best defined by 50% mercury saturation. Plots constructed using R50 pore aperture correlation indicate the pore throats of the productive sands to be macro to mega porous. R50 pore throat radius is defined as the pore throat on a capillary pressure curve where the non-wetting fluid saturates 50% of the porosity.
Rocks in the area were divided into four petrophysical categories based on pore geometry classification. Rock types A and B present the best petrophysical characteristics and highest production rates, whereas rock types C and D have poorer petrophysical characteristics and generally do not contribute to production.