A Novel Completion Method for Sequenced Fracturing in the Eagle Ford Shale

Abstract

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 169010, ’A Novel Completion Method for Sequenced Fracturing in the Eagle Ford Shale,’ by C. Kraemer, SPE, B. Lecerf, J. Torres, SPE, H. Gomez, and D. Usoltsev, SPE, Schlumberger, and J. Rutledge, SPE, D. Donovan, SPE, and C. Philips, SPE, Marathon Oil, prepared for the 2014 SPE Unconventional Resources Conference—USA, The Woodlands, Texas, USA, 1-3 April. The paper has not been peer reviewed. Evenly fracturing all clusters in heterogeneous zones is challenging in long horizontal sections penetrating heterogeneous reservoirs, as is often the case in the Eagle Ford shale. Furthermore, efforts to improve well economics result in reducing completion time by extending the length of each stage even farther to decrease the number of interventions required for completing the well. To address this challenge, a new sequenced-fracturing technique has been developed on the basis of a novel composite fluid comprising degradable fibers and multisized particles. Introduction In Eagle Ford shale completions, which typically rely on limited-entry principles, the distribution of fluid flow is a function of fracture initiation and propagation pressure, differential pressure on perforations, and net pressure of the stimulation treatment. New injection-evaluation and logging techniques demonstrated the possibility of significant variations in fracture-gradient anisotropy and formation fluid-flow distribution over the intervals of horizontal wells. Recently, several operators in the Eagle Ford play revised their completion strategy and decided to increase differential pressure on perforations by reducing the number of perforation clusters per stimulation stage. This approach requires a larger number of wireline interventions to place the additional necessary bridge plugs and is accompanied by longer subsequent coiled-tubing milling operations. A solution was needed to increase the number of perforations being stimulated without increasing the complexity of operations, the associated time, and the costs. Increasing Contact, Not Operational Complexity Chemical diversion has been proposed as a cost-effective and faster alternative to mechanical techniques for isolating perforations and forcing fluids into previously unstimulated portions of the reservoir. Numerous materials (e.g., benzoic acid flakes, rock salt, fracturing balls, and rubber-coated neoprene balls) are commercially available for this purpose, but none was found to provide reliable diversion. The sequenced fracturing technique described here introduces a composite fluid that temporarily plugs zones that were previously stimulated and diverts fluids to understimulated regions. The composite fluid overcomes the limitations of traditional chemical diverters by coupling degradable particles of a wide size distribution.