Proper Diagnosis of Formation Damage Can Result In Higher Productivity

Most exotic fluids introduced into a reservoir will cause reduction in permeability near the wellbore. Dispersed water base fluids and oil base fluids create their own unique problems, such as wettability changes, and emulsions. Prior knowledge of what drilling fluids can do to a formation will, upon completion, lead to a better diagnosis of well behavior and thus resulting in more effective clean-up and stimulation procedures. Hydrochloric acid (HCL) as a stimulation fluid has been and continues to be misused as a method to increase reservoir permeability. Incorrect application can either create a problem greater than the original and/or cause unnecessary expense to the operator. The cause of productivity impairment should first be determined before a stimulation procedure is selected. Scanning electron microscopy, X-ray diffraction, thin section petrography and core-flood analysis are effective techniques in determining the sensitivity of a reservoir to foreign fluids. Rock-to-fluid and fluid-to-fluid compatibility tests are extremely important to improve stimulation procedures and to ultimately improve production. As money for drilling and completing wells gets scarce, proper utilization of current technology can result in a higher return of investment.