The Evaluation of the First Biodegradable Diverter in Acid Fracturing in Kuwait: Case Study

Abstract Numerous methods have been applied in matrix acidizing over the previous decades to successfully stimulate multiple zones. These methods have also been implemented in fracture acidizing with varying degrees of success. This paper discusses the application of a new biodegradable material used for diversion in multiple zones or long formation intervals and presents improved results obtained using a new biodegradable diverter. Acid-fracturing diversion can be more challenging than diversion for matrix acidizing. To effectively stimulate multiple or large zones, the diversion treatment should be able to bridge not only the perforations themselves, but often inside the fracture system as well. This can be difficult because acid reacts with the rock, forming an etched/enlarged path, thus the diversion also requires bridging inside this conductive path. This differs from matrix acidizing techniques, in which the diversion depends mostly on the perforations in an interval(s) and the stimulated reservoir permeability. Historically, several methods have been implemented for acid-fracturing diversion, such as ball sealers, viscous fluids, packers, etc., resulting in limited success or cost-ineffective results. The new biodegradable material helps improve acid fracturing diversion success in multiple zones or long formation intervals. The development of this biodegradable material is discussed along with a case study. Also, details are provided of the biodegradable material evaluation that consists of 1) pre and post-temperature logs, 2) pre and post-injection logging profiles, 3) pre and post-production history, and 4) further recommendations. The results of the evaluation methods show that the biodegradable material can be used as an effective alternative diversion method to seal existing perforations and effectively stimulate all perforated intervals. Production increased more than threefold, and the targeted fracture height was achieved based on the temperature log data.