Optimization of Selective Stimulation Treatments Using Coiled Tubing and Fluidic Oscillator Yields Additional Oil Production from Carbonate Formations in Southern Mexico: Case Studies

Abstract

This paper documents efforts to seek alternative and effective treatments for stimulating wells in southern Mexico. It was desired to make treatments more selective, stimulating only areas of oil without contacting contributing areas of water or gas. Stimulation treatments were performed using coiled tubing (CT) and a fluidic oscillator to generate waves of fluid.In the southern region of Mexico, the commercial production of hydrocarbons is in reservoirs that are naturally fractured carbonates with permeability of 25-150 mD, porosities of 5-15%, and are depleted as a result of exploitation. Also, the progress of oil-water contact and gas-oil contact present challenges when designing treatments for stimulation.The damage mechanisms encountered in these wells included blockage by water, paraffin, asphaltenes, and scale depositions, which were generated in the near-wellbore area of the well.To enhance the effect of the stimulation systems, the fluidic oscillator was used to generate a frequency of impact of 300 to 600 Hz on the formation, weakening the damage and efficiently removing it.Commonly, in the southern region of Mexico, 90% of the stimulation treatments are bullheaded; however, in highly deviated wells with two or more pay zones, the use of CT with the fluidic oscillator offers an alternative to increase the effectiveness of acid placement.The synergy of CT, the generation of fluid waves, and the selection system for optimal acid flow through each hole have led to significant results of reduced cost, time, and, in turn, optimizing the volumes of systems required to stimulate wells.In this paper, results achieved by carrying out selective stimulation treatments as well as technical and economic benefits of using CT and the generation of fluid waves as an alternative stimulation treatment for oil wells are presented.

A Successful Application of Near-Wellbore Stimulation Using Fluidic-Oscillation Technique in North Africa Oil Field

“…There are no moving parts and the tool does not rely on cavitation to create pressure waves. including gravel packing and frac packing • Removing fill from openhole or casing • Optimizing injection profiles FO tools have been applied successfully in a wide variety of downhole applications for sandstone (Kritsanaphak et al 2009) and carbonate formations (Rodríguez et al 2009), oil and gas wells (Hegazy 2007;McCulloch et al 2003), vertical and horizontal wells (Gunarto 2004) with gravel-packed completions (Hartly et al 2004), straddle completions (Willemse et al 2005a), and other difficult completions (Willemse et al 2005b). Any nonabrasive fluid suitable for use in downhole conditions can be used to help remediate a number of problems.…”