Global Energy Development plc announced an update on the operations of the Catalina #1 Simiti formation in the company's Bolivar Association Contract located in the northern section of the Magdalena Valley in Colombia, South America. The Catalina 1 well was stimulated using 27,000 barrels of water pumped into the Simiti formation. Upon completion of the process, the stimulation fluids initially began to flow back from the formation into the wellbore at high rates but quickly declined.

Currently, approximately 6,750 barrels of the injected fluid has been recovered. The company has obtained useful information from the testing process, as follows: The crude oil recovered demonstrated light oil gravity ranging between 28 and 30 API. Pressure build-up analysis confirmed higher than normal reservoir pressure within the formation with a gradient of 0.52 psi per foot which is above the normal gradient of 0.465 psi per foot.

Production tests indicated low productivity of between 75 barrels of fluid per day (bfpd) to 125 bfpd in the Simiti formation. Both low pressure and high pressure post-stimulation injectivity tests were performed. The low pressure test was three times the injectivity of the high pressure test, indicating favorable permeability in the Simiti formation.

This is consistent with actual stimulation data which demonstrated higher permeability and natural fracture frequency than original engineering estimates, completed prior to stimulation operations. The higher formation permeability was further confirmed by the constant rate of injection and pressure throughout the stimulation process. Such high levels of preexisting permeability are believed to have allowed the stimulation water to scour the formation of the existing oil saturation and push it away from the wellbore.

All of this information has been used to analyse the cause of the low rate of fluid recovery from the Simiti which the company has diagnosed as being caused by the presence of an emulsion substantially blocking most reservoir fluids from reaching the wellbore. The use of sand in the stimulation process is likely to have collected at the oil-water interface and acted as the agent to create the emulsion. The company is currently working to remove this blockage by inducing pressure surges within the formation, in order to form a corridor to allow oil to pass through the emulsion.

This process should ultimately cause the emulsion to break to allow fluids, both oil and water, to pass into the well at higher rates. If the surging process is not effective in removing the emulsion blockage, the company will consider other techniques for dealing with the emulsion, including a work over of the well to chemically remove the emulsion.