Case Study of Successful Matrix Stimulation of High-Water-Cut Wells in Dubai Offshore Fields

Abstract

TX 75083-3836, U.S.A., fax +1-972-952-9435. AbstractThe candidate selection criteria, job design, and improved implementation techniques are important parameters for success in remedial acidization jobs in mature fields.Effective acid diversion across heterogeneous carbonate reservoirs has always been challenging and is even more difficult when stimulating high-water-cut wells. For these types of wells, it is crucial to stimulate the oil-saturated layers rather than the watered-out layers. Bullheading conventional stimulation treatments tend to result in the aqueous-based stimulation fluid being injected into the high-water-saturated zones and away from the high-oil-saturated zones. This often results in a dramatic increase in water productivity and a minimal gain in incremental oil.Recently, several of Dubai Petroleum's offshore oil wells have been treated using 15% hydrochloric acid (HCl) and a viscoelastic-surfactant (VES)-based diverter, resulting in a significant uplift in oil production and a decrease in water cut. The VES diverter permits the oil-saturated zones to be stimulated while minimizing the stimulation impact of the water zones, despite large permeability contrasts. This VES fluid is able to maintain its viscosity when in contact with water and it breaks when in contact with oil. The increase in production with decreasing water cut showed the success of this stimulation diversion technique.This paper describes the candidate selection criteria, design, and implementation of successful carbonate matrix stimulation for high-water-cut wells in mature, water-flooded offshore fields.

A New Methodology for Stimulation of a High-Water-Cut Horizontal Oil Well through the Combination of a Smart Chemical System with Real-Time Temperature Sensing: A Case Study of South Umm Gudair Field, PZ Kuwait

“…Numerous papers have reported the success of deploying "smart fluids" whose viscosity builds up upon contact with water and breaks down upon contact with hydrocarbons ) (Soekama et al 2003) (Shnaib et al 2009), as a means of temporarily plugging the water zones and diverting the subsequently pumped acid to the next available oil zones. As explained in Chang (Chang, Thomas & Fu 1998), the material becomes a viscous gel when contacting brine and degrades when contacting oil.…”