Unconventional Fracturing Fluids for Unconventional Reservoir Challenges

Abstract

To overcome the challenges specific to unconventional reservoirs that are being targeted across the Middle East region a synergy of unconventional technologies is needed. Fracturing fluids are one of the critical components of multi stage proppant fracturing solution when targeting extreme HPHT reservoirs while aiming to preserve freshwater. The objective of this paper is to reveal the performance of unique fracturing fluids that have been recently tailored and applied to tackle tight and unconventional reservoir challenges. Three very different unconventional: polymer-free, carboxymethyl hydroxypropyl guar (CMHPG) and poly-acrylamide based fracturing fluids are presented in this work. They have been field-tested and recently successfully applied in the tight and unconventional reservoirs of UAE as well as the Middle East and Asia. These fracturing fluids collectively address the full spectrum of existing and future reservoir target bottom-hole temperatures ranging from 50 degF up to 450 degF. The unique chemistry characteristics for each of the fluids will be elaborated together with laboratory test results that will include compatibility, rheology and other qualification tests. Furthermore, results of extensive qualification tests performed to address specific local challenges will also be presented. All three fracturing fluids were effectively applied leading to treatment success and proving their performance in extreme reservoir temperature, stress or operational environment that demands high-efficiency. Each fluid proved compatibility with used mixing water and reservoir fluids tested. These fracturing fluid types can be continuously mixed simplifying operation, reducing fracturing equipment layout and minimizing waste. All these improvements are critical in an offshore operating environment. Polymer-free and CMHPG based high viscosity fluids are formulated with sea water to minimize environmental impact. Furthermore, these fluids are continuously mixed with seawater addressing the conventional fracturing fluid logistic constraints offshore. These key improvements made massive offshore and multi-stage proppant fracturing treatments technically and economically feasible. The novel unconventional fracturing fluids elaborated in this paper offer a set of unique technical capabilities that did not exist previously. These three fluids are critical technology enablers and they are part of a multi-disciplinary, integrated technical collaboration project aiming to efficiently and effectively address local complex subsurface conditions and stringent economic requirements of remote offshore operations.