Petrobras highlights technology in Libra at Offshore Technology Conference (OTC)

HOUSTON -- At the 50th edition of the Offshore Technology Conference (OTC), Petrobras will highlight its technological journey to enable one of the main exploration and production projects of its portfolio: the development of the Libra block in pre-salt of the Santos Basin.

Libra is one of the company's great bets for the future not only for its production potential, but also for its ability to drive the development of innovative technologies for the entire industry. The five technologies used in Libra were crucial for Petrobras to have reached the average monthly production record through a single offshore well. The volume produced by this well reached more than 60 thousand barrels of oil equivalent (boe) per day.

Get to know the 10 awarded Pre-Salt technologies

The technologies that enabled production in the inhospitable pre-salt conditions have been tested, proven, and today represent an important legacy for the oil industry.
Highlights include the development of different subsea collection pipeline system solutions, new well construction solutions, and the design of CO₂ separation and injection systems to face the challenge of not releasing the CO₂ that is produced to the atmosphere.

First Buoy Supporting Risers (BSR). Risers are pipelines that take oil or gas from the seabed to the platform. In order to sustain the risers that are connected to the wells' subsea pipelines, buoys are installed at a point between the seabed Ocean floor, bottom of the sea and the surface of the sea (about 250 meters in depth). This allows them to be connected to the FPSOs (floating production, storage and offloading units) through flexible tube spans. With this setup, the floating platform's movements are not transferred in full to the rigid risers, reducing the damage caused by fatigue and ensuring their useful life even under severe meteocean conditions. Two buoys were installed in the pilot project carried out for the Sapinhoá field and two in the Lula field (in the pilot project for the Lula Nordeste area), or a total of nine wells currently in production.

First steel catenary risers (SCR) with lined pipes installed using the reel lay method. Rigid risers called Steel Catenary Risers (SCR) have been installed supported directly on the Buoy Supporting Risers (BSR). These were the first of the SCR-type risers that used carbon steel pipes lined internally with a corrosion-resistant metallic liner. Special procedures and qualification tests enabled the use of these pipes under dynamic conditions (such as risers) and enabled installation using the reel lay  method.

Deepest Steel Lazy Wave Riser (SLWR). Steel Lazy Wave Risers (SLWR) are steel risers that are installed with a set of floats that form a humped configuration and are connected directly to the floating production unit. This is the first system of its kind in the world to be connected to an FPSO with spread mooring designed and built to withstand the movements of the vessel platform in the adverse pre-salt environment. The first SLWR deployed in the pre-salt is at a water depth of 2,140 m, interconnected to FPSO Cidade de Ilhabela (Sapinhoá Norte project).

Deepest flexible riser (in a water depth of 7,021 ft). The flexible riser consists of a multilayer pipe (parts made of metallic material and parts made of polymeric material) that transfers the oil and/or gas from the well on the seabed to the production platform. To operate in the pre-salt, it underwent specific development to meet the conditions in corrosive atmospheres and ultra-deep waters. The flexible riser operating at the greatest depth (7,021 ft) was installed in the Lula field, in the Iracema Sul project. There are already more than 35 flexible risers operating in the Santos Basin, producing oil and natural gas.

First application of flexible risers with an integrated wire traction monitoring system. System based on optical fibers that are attached to the flexible risers' tensile armor wires. The system allows identifying wire breaks, sending warning signals in order for maintenance actions to be taken to keep damage from spreading. The risers are already being installed with coupled sensors to be connected to the control room on the platform.

Water depth record (6,900 ft) for a subsea well drilled using the Pressurized Mud Cap Drilling (PMCD) technique. During the well construction process, a fluid known as drilling mud is put into the borehole to maintain pressure, keep its walls from collapsing, and to take gravel to the surface. In a few rock sections where there are fractures or caves, drilling mud seeps into the rock - a phenomenon known as "loss of circulation" -, rendering well progress difficult or even preventing it. The use of the PMCD technology enables drilling in this scenario and reduces time loss. This technology was used in an unprecedented way in terms of depth at the Lula-19 well, in the midst of a scenario characterized by large losses of circulation, where conventional drilling is not feasible.

First intensive use of intelligent completion in ultra-deep water satellite wells. Completion is the set of operations carried out to equip the well to produce oil and gas or to inject fluids in the reservoir. With intelligent completion, it is possible to produce simultaneously from two or more reservoir zones using valves that are closed or opened remotely from the platform control room. The intelligent completion technology has been used intensively in the pre-salt, having been installed at 22 wells until March 2015.

First separation of carbon dioxide (CO₂) associated with natural gas in ultra-deep waters (7,283 ft) with CO₂ injection into producing reservoirs. In a few pre-salt wells, the oil that is produced is associated not only with water and natural gas, but also with CO₂. The CO₂ that is produced is separated from the oil and natural gas using a sophisticated membrane system that separates carbon dioxide molecules from the other fluids through the selective permeation of gas molecules (H2S, CO2, CH4, etc.) by the plastic seal layer. We use this separation technology and CO₂ reinjection in offshore environments located at great depths. The technique was first adopted in the pilot project for the Lula field, where we set the global record of the deepest subsea well with gas injection with CO2 at water depths of 2220 m.

Deepest offshore well injecting gas with CO₂ (7,283 ft meter water depth). At the Lula field pilot project, one of the CO₂ injection wells is located at a record water depth of 7,283 ft. In addition to the benefits for the environment, the reinjection of the produced CO₂ increases the internal pressure in the reservoir, improving oil recovery.

First use of the alternating water and gas injection method in ultra-deep waters (7,218 ft). This technique has been being used and evaluated in the Lula Pilot System since June 2013. The main advantages are reservoir management optimization and the expected increase in the oil recovery factor.