Evaluate Fracturing Fluid Performance for Hydraulic Stimulation in Pre-Khuff Sandstone Reservoirs of Ghawar Gas Field

Abstract

Abstract The choice of stimulation fluids and proppants are very important for successful proppant fracturing. Saudi Aramco along with a few service companies had put lot of efforts on the development of the Ghawar gas field mainly in the Pre-Khuff sandstone formations in the past years. A good understanding of the fracturing fluids and its performance downhole is the key to successful stimulation of gas wells. The design of a fracturing fluid depends on several reservoir properties such as bottomhole static temperature, reservoir fluid properties, formation permeability, rock mechanical properties etc. The pre-Khuff reservoir possesses very high temperature (in the range of 290-3400F) and high fracture gradient (0.6-0.95). Choice of particular fluid systems used during proppant fracturing is mainly governed by the bottomhole static temperature, treatment time and cost. Different types of borate-crosslinked, metal-crosslinked and viscoelastic fluid systems were used in the past with different proppant concentration. One of the major concerns with the crosslinked fracturing fluids is the damage created in the formation due to non-uniform broken fluid and unbroken gel left inside the formation after the treatment is performed. The paper provides an assessment on different fracturing fluids pumped in pre-Khuff sandstone formations and compares the performance in terms of formation damage and well deliverability from actual case histories. The paper also provides recommendations that can be implemented to assess and minimize formation damage from unbroken gel and achieve improved production. The paper provides an overview on the different fracturing fluids, current design practices, probable damage severity due to unbroken gel and fracturing fluid performance with respect to production improvement through case studies. The study can be used as a lesson learnt for selection of right stimulation fluid and evaluation of formation damage due to fracturing fluid performance for other reservoir conditions.