Abstract
The conducted study is aimed to investigate on temperature and pressure variation applied to carbonate reservoirs and their petrophysical characteristics mainly permeability.
In the laboratory, intensive runs of flooding experiments were carried out at different effective pressure up to 4000 psi and temperature reaching 100 °C using carbonate samples from Middle East reservoirs. This investigation was aimed to examine fluid circulation behavior coupled to probe on textural examination of the carbonate samples. This latter was achieved by the use of ordinary microscope and scanning electron microscope (SEM).
Results indicated that permeability reduction can be controlled by variation in pressure and temperature: permeability reduction corresponds to pressure and temperature increase. It has been found that a wise permeability reduction start to be recorded above a value of 50 °C with reference to initial permeability at 25 °C. Furthermore, the permeability reduction has reached 59 % at an effective pressure of 4000 psi and a temperature of 100 °C compared to initial permeability at 725 psi and at 25 °C. According to the overall results, the effect of temperature on permeability reduction in the applied carbonate samples is as important as that of the effective pressure.
Various processes can be suggested for such diverse changes. However, packing and compaction leading to rock deformation and elasticity rock property remain among the main factors responsible for such statement. In addition, and based on the experimental and textural work led, it is important to notify that no formation damage has been notified.
