Damage Remediation in a Mature Field Reservoir by Applying a Customized Treatment Using Surface Active Additives and Diversion Technologies: Case Histories from San Francisco Field

Abstract

This paper discusses successful damage remediation performed in more than 10 wells in a mature oil field producing under a developed waterflooding project in Colombia. The primary damage mechanism observed is associated with a detriment to production related to reduced relative permeability caused by wettability preferences.A chemical treatment was proposed that consisted of crude oil with efficient and effective surface active additives, such as microemulsions (MEs) and/or formation mobility modifiers (FMMs) and associative polymers (APs) for a proper diversion. The treatment was proposed as an effective method to restore near-wellbore (NWB) permeability in or through the damaged zone in the formation, resulting in production recovery. All matrix-stimulation treatments were conducted rigless by means of an annulus without affecting the artificial lift method and resulted in a significant time and cost savings.Laboratory data confirmed the ability of the MEs and FMMs to modify interfacial tensions (IFTs) and contact angles. These materials helped promote a change in the degree of wetting of the system, which is dependent on the adhesion tension (the product of the IFT by the cosine of the contact angle). During well treatments, surface pressure spikes during the diversion stages were associated with the arrival of the APs at the perforations and were clearly observed during the development of the treatments, revealing that effective diversion was achieved. Finally, post-stimulation treatment data have shown positive results, confirming the effectiveness of combining these technologies. This paper discusses how the synergy of using surface active additives with diversion technologies can yield productivity increase in mature oil reservoirs and improve the level of sustainability of current field production.