Intelligent Completion Installations Instrumental in Brazilian Presalt Development
Authors: Carpenter Chris 
Published: April 2020

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 195935, “Hundredth Intelligent Completion Installation: A Milestone in Brazilian Presalt Development,” by Eduardo Schnitzler, SPE, Luciano Ferreira Gonçalez, and Roger Savoldi Roman, Petrobras, et al., prepared for the 2019 SPE Annual Technical Conference and Exhibition, Calgary, 30 September–2 October. The paper has not been peer reviewed.

Presalt heterogeneous carbonate reservoirs typically present long net pays, high production and injection rates, and flow-assurance risks. The complete paper presents a discussion of the use of intelligent well completion (IWC) in Santos Basin Presalt Cluster (SBPSC) wells. With the use of this technique and the introduction of several improvements, well-completion time was reduced to less than 50% of that seen in initial wells.

Introduction

The SBPSC is in ultradeep water—be-tween 1900 and 2400 m—approximately 290 km offshore Rio de Janeiro. From the opening phases of SBPSC development, IWC has been crucial, not only to improve reservoir management but also to provide better capability to deal with reservoir uncertainty. Extensive use of IWC has presented challenges for well-engineering teams because of the complexity associated with this completion design. Minimizing well-construction costs and risks is essential for any project, but, in ultradeep water, it is even more critical.

Intelligent Completion Systems Internal risk assessments were conducted to determine optimal solutions for the first production-development project. Direct hydraulic systems were chosen to actuate interval control valves (ICVs) remotely in two- and three-zone wells. This field-proven system was considered the simplest and most reliable for long-term use. However, because the wet tree (WT) designed for SBPSC projects comprises multiplex control systems, addressing these additional integration issues during the planning phase demands exceptional efforts. An extensive integration process had to be conducted to assure that every interface would perform correctly during the production phase.

Most projects consider the use of a 95/8- or 97/8-in. production casing set and cemented in front of the reservoir, allowing the use of wider completion equipment, including IWC components. The use of larger-diameter accessories provides the production string the capability to deal with higher mechanical loads, a feature important in the absence of an expansion joint.

The full completion string, installed in a single run, has no separated lower completion system. This integral completion design avoids the use of down-hole connections and allows control lines to be run continuously during deployment and the equipment functionality to be tested fully during installation.

Dedicated pressure and temperature sensors are located on each interval and inside the completion string. For two-zone production wells, three chemical-injection points are available. Two of them are upstream of the ICVs to prevent scaling formation in the valves by injecting scale inhibitors in the annulus. These chemical-injection points are especially important when producing the well with any of the ICVs in choked positions, leading to higher-pressure drops across the valves. A third chemical-injection system, injecting into the production string, is above the upper packer and may be used for a second chemical injection or as a backup for the main chemical-injection systems.