The Effect of Pressure and Temperature on Pore Volume Compressibility

Abstract Pore volume compressibility is one of the physical properties of a reservoir that must be specified in many reservoir engineering calculations. In this research, the effect of compacting pressure, temperature and porosity on compressibility was investigated. A total of nine different cores were tested, eight were sandstone and one was limestone. Core samples were placed in copper jackets and subjected to compacting pressure up to 15,000 PSI. Runs were made pressure up to 15,000 PSI. Runs were made at room temperature and at 400 degrees F. Very late has been published concerning the effect of temperature on the pore volume compressibility of reservoir rock. This work shows that the pore volume compressibility increases with increasing temperature for the same pressure. In most cases, about a twenty percent increase in compressibility was noted at 400 degrees F. as compared to room temperature. The compressibility was found to be a continuous function of compacting pressure. The compressibility at 14,000 PSI compacting pressure was only about one-third of the pressure was only about one-third of the compressibility at 1,000 PSI. From the research that has been performed, no method has been found for performed, no method has been found for accurately predicting pore volume compressibility. Therefore, when accurate compressibility data for a reservoir are needed, laboratory measurements should be made on core samples from the specific formation simulating reservoir temperature and compacting pressure. Introduction In the past few years, much emphasis has been placed on sophisticated reservoir engineering such as mathematical reservoir models and transient reservoir flow tests. One of the physical properties that must be specified in this type of work is the pore volume compressibility of the reservoir rock.