Interpretation of Bottom Hole Temperature Data from CO2 Injection Projects

Abstract

A new approach is presented for analyzing bottom hole temperature (BHT) data from CO2 injection projects. The basic premise of the methodology is: (a) during injection, both bottom hole pressure (BHP) and BHT approach quasi-stabilized values, and (b) the ratio of these changes (from ambient conditions) is the same as the ratio of slopes from transient Horner analysis of temperature and pressure data from the subsequent warmback/falloff periods. Once the slope of the pressure Horner plot is estimated from a steady-state temperature-pressure change cross plot and the slope of a temperature Horner plot, the formation permeability can be readily determined. This provides an independent estimate of formation permeability without utilizing transient pressure data.

Keywords: CO2 injection, bottom hole temperature, bottom hole pressure, Horner analysis, permeability