Steam/bacteria to treatment of asphaltene deposition in carbonate rocks

Abstract

In this project, steam and bacteria were tested to stimulate the damaged limestone cores. Several dynamic experiments were conducted to determine the effect of asphaltene on the permeability of limestone cores. Plugging effects due to asphaltene deposition were evaluated through comparison with reference permeability measured prior to and after oil flow. Damaged cores were subjected to different type of treatments: a steam soak process and bacteria. The permeability of the cores was measured after each treatment. Core impairment resulting from in situ asphaltene deposition, was found to cause an 8% to 93% loss of initial oil permeability depending on rock permeability and injection rate. Core stimulation resulting from steam soak treatment, was found to cause an 18% to 400% improvement on the damaged core permeability depending on rock permeability and soaking time. Core stimulation results from bacteria treatment, was found to cause a 41% to 129% improvement on the damaged core permeability depending on core permeability and the extent of the damage.