Management of Flow Assurance Constraints
Authors: Cardoso Carlos Bandeira , Alves Iberê Nascentes , Ribeiro Geraldo Spinelli 
Published: October 2008

Flow Assurance started to be a concern in PETROBRAS in the mid 80's, with the development of the Albacora Field, which was the first field produced at a water depth below 400 meters in Campos Basin. Since that time, PETROBRAS relies heavily on technological research and development to provide solutions that can grant the safe, continuous and optimized operation of its subsea fields. This paper reviews the efforts regarding Flow Assurance Management in Campos Basin, under a historical point of view, following the new challenges that were posed as water depths became deeper and deeper, and the techniques and practices developed to face them. Also are reported here the current R&D efforts under the PROCAP- 3000 program, aiming to address Flow Assurance Management in water depths up to 3,000 meters (9,840 ft).

Introduction

Since Flow Assurance started to be a concern in PETROBRAS in the mid 80's, with the development of the Albacora field, large investments have been made in R&D, through the PROCAP program, aiming to make viable the production and pipeline transportation of oil in this harsh environment, at water depths below 400 meters in Campos Basin. This scenario is where the occurrence of waxes, hydrates, asphaltenes and scale become a critical issue.

The first challenge faced in the beginning of the production of the Albacora Field was to keep the continuous operation of the pilot production system, which was not originally designed to handle the large degree of wax deposition that was taking place in the production lines. The first solution was to change the production line, which was very expensive and did not really solve the problem. This challenge was overcome with the in-house development of the thermo-chemical method known as SGNTM ?Nitrogen eneration System. The lessons learned with this pilot system were the driven forces of the development of methods to predict and prevent wax deposition, which will be discussed in this paper. These methods incorporated a new way to design the production system, and were eventually used with success in the development projects of subsequent fields in Campos Basin, such as Marlim and Roncador.

When the development of Marlim took place, in the early 90's, already reaching water depths of 1,000 meters (3,280 ft) and below, cases of hydrate formation started to appear, initially in the completion phase. With the increase of the BSW in the production phase, hydrate formation in production lines and subsea equipment also became a problem. Taking a similar strategy to the one used for dealing with wax deposition in Albacora, PETROBRAS invested in the research and development of methods to predict, prevent and control hydrate formation in the production of deep offshore fields.

Nowadays in PETROBRAS, and particularly in Campos Basin, Flow Assurance is still a problem and a challenge for this production scenario. But the learning process and the investment made in R&D turned the Flow Assurance Management a well-developed and successful issue, which extends its scope beyond the waxes and hydrates formation phenomena, dealing also with strategies to control scaling, emulsions, asphaltenes and severe slugging as well.