August 2013, Vol. 240 No. 8
Features
Transpetro Gas Pipeline Operations In Heart Of Brazilian Amazon Rainforest
Transpetro, a company 100% owned by Petrobras, is the largest logistics and transportation company in Latin America for the oil and liquid byproducts segment, and the national leader of natural gas transportation and processing. It is present in more than 200 cities and every Brazilian region.
The company stores and transports oil, byproducts, biofuels and natural gas to the farthest locations of Brazil. Transpetro is also considered the largest natural gas processor in Brazil. Now, it is being structured to receive Brazilian oil and gas from the future pre-salt production. This is its new challenge.
The pipeline network is operated and controlled around the clock from the National Center for Operational Control (CNCO) at Transpetro´s headquarters in Rio de Janeiro. It uses the latest generation computers and technology in telecommunications.
Marcelo Rennó was nominated as natural gas director of Transpetro in 2005 and has been involved with the pipeline operations in the heart of the Brazilian Amazon rainforest since they began four years ago. He is also the coordinator of the Pipeline Commission of the Brazilian Petroleum Institute (IBP), a non-profit institution dedicated to training and certification for the oil and gas industry, which hosts the “Rio Pipeline Conference” every odd year, an international event that is going to take place in September in Rio de Janeiro.
Commissioning, Operations Start Up
The Amazon Pipeline Natural Gas System consists of two single lines, in series, and nine delivery branches along the lines. It totals about 820 km of pipeline. The first pipeline links production fields in Urucu-AM to Coari-AM. This is an 18-inch line that is 280 km long. At the time of the system’s construction, the pipeline was already operating with liquefied petroleum gas (LPG). In 2008 it was converted to a natural gas pipeline.
The second pipeline from Coari-AM to Manaus-AM, the state capital, was built in 2008 mainly to supply power plants. It is a 20-inch pipeline, 382 km long, and crosses the rainforest and dozens of lakes and rivers including the Rio Negro at a 10-km-long crossing. The Urucu-Coari-Manaus gas pipeline also supplies natural gas to seven intermediate consumers (Figure 1).
Figure 1: Brazil map and Amazon Pipeline Natural Gas System
This pipeline system is isolated from Transpetro’s pipeline grid that goes from the very south of Brazil to the farthest northeast reaches. The electric power generated from the natural gas reservoir in the Amazon forest will be connected to the Brazilian electric energy grid by the ongoing construction of an 1,800-km, high-voltage electricity transmission line. This construction is also a challenge for Brazilian Electric Power Industry because it is constructed in the heart of the Amazon rainforest. It is scheduled to start operations in 2014.
Pipeline Operations
The system started operations in July 2009 with an initial flow rate of 1.8 million m³/d of natural gas consumed at the end of the line in Manaus, supplying thermal generation plants. At that time, all the gas was compressed from the production field at the beginning of the line. Currently, the flow rate is about 4 million m³/d.
There are now two compression stations in operation, at Juaruna-AM and at Coari-AM. For the future, the plan is to construct three more compression stations (Cajual-AM, Cutia-AM and Codajás-AM), increasing the gas pipeline capacity to 10 m³/d.
The entire pipeline system is remotely monitored and operated through the control center (CNCO) in Rio de Janeiro (Figure 2), almost 4,000 km from Manaus. Compression stations, pipeline alignments, shutdown valves, city gates and pressure reduction stations along the main line are mostly remotely operated. The CNCO uses supervisory control and data acquisition system (SCADA), to control and operate the system. The main communication system is based on two optical fiber channels, one being a backup of the other. There is another alternative channel based on a satellite signal to ensure maximum reliability.
Figure 2: The control center in Rio de Janeiro.
Right-of-Way Maintenance Logistics
The rainfall in the Amazon forest is among the greatest in the world with annual averages exceeding 2,000 mm, reaching as high as 10,000 mm in some regions. During the wettest months, from November to June, large areas are flooded and water rises an average of 10 meters, reaching 18 meters in some areas. This means for roughly half the year much of the ROW’s influence area is submerged.
The region’s characteristics are, therefore, unique with a plain crossed by a complex arrangement of soils of various types and swampy environments that change significantly, depending on the season (dry or rainy).
During the dry season, the water recedes, leaving many seasonal beaches of sand or mud. Due to its generally low permeability, the soil is inappropriate to support heavy machinery or equipment, even with adaptations. Added to this is the uneven topography in some areas – steep inclines followed by flat areas containing several swampy environments. No single vehicle can be adapted for these varying terrain conditions. Figure 3 shows the water level variation model in a typical one-year period. It reflects that rivers take eight months to rise in the wet season and four months to fall in the dry season. As a consequence, the logistics are highly complex and expensive. Figure 4 shows the difficultly in accessing the ROW by cars.
Figure 3: Water level variation model for the Amazon in a typical one-year-period.
Figure 4: Vehicles on a routine patrol.
Many other logistics problems created by the environment are associated with the rain cycle.
Several cities along the pipeline route are completely flooded during the rainy period. Floating hotels (Figure 5) have to be used to support field workers. Along the mainline, only the first 50 km after the Urucu base and about 120 km, from Manacapuru to Manaus, allow access to the ROW by car. The rest of the ROW, more than 600 km, is only accessible by boats or helicopters. Every shutdown valve has a helipad to guarantee access as they are important spots for the maintenance process. Communications is another big concern, to ensure safety to the workers wh need to use satellite cell phones, (Figure 7).
Figure 5: Floating hotel space is needed to support the workers.
Figure 6: Various communication equipment used by workers.
The rainforest environment comes with more tough tasks that demand specific personnel skills. The forest contains areas with high biodiversity that have to be preserved. Animals and poisonous snakes, spiders and scorpions are a common sight along the ROW. Infectious diseases that come from mosquitos are endemic in tropical forests and can cause malaria, dengue fever and yellow fever. This is a constant worry for Transpetro, which uses mitigation methods such as installation of grids on the accommodations, to prevent mosquitos from entering.
Extremely diverse wildlife can be found in the region, from spiders to big-cat species (jaguars, black jaguars and pumas). Those animals have territorial behavior, and it’s not usual to see attacks against humans, such as in the case with Alison da Silva Pedro, who has been working at Transpetro for six years as an ROW inspector, patrolling the route to prevent third-party damage and geotechnical problems.
He reported about an year ago: “… during a routine patrol at a place called Boca da Onça (Jaguar’s Mouth), I decided to relocate myself in a line of five other co-workers, moving to the last position. Suddenly, I came across a puma preparing for attack in the middle of the right-of-way between myself and the preceding line inspector. I yelled to warn my colleague of the imminent danger, and the puma turned and stared at me! Just when the other inspectors started shouting, the puma ran away, springing 10 meters into the dense forest.”
Due to the interaction of Transpetro’s workers with the Amazonian wildlife, specific training to better understand the behavior and habits of the region’s animals is an important control measure.
Emergency Response
Brazil is a huge country with a great variety of environments, geography, topography, geology and hydrology. Because of this, the company applies the best operational and pipeline inspection practices with a well-established structural integrity program.
As any pipeline operator, Transpetro has to be prepared to promptly respond to failures – spill and leaks – to prevent harm to people, the environment or company assets, as well as to preserve operational continuity. Specifically for the rainforest climate, Transpetro has to prevent failures and the minimize the likelihood of failure during different seasonal scenarios. Figure 7 shows the same ROW spot in two different seasons.
Figure 8: A specific spot at the ROW in wet and dry seasons is a study in contrast.
Taking into consideration the environmental sensitivity of the Amazon forest, Transpetro has prepared detailed procedures to respond to leaks and ruptures at any point along the ROW. A specific procedure to coordinate all parties for an emergency response is continuously disseminated to the entire workforce. Another procedure provides the orientation for preparation in terms of training needs, resources, equipment, tools and contacts for contract personnel or equipment.
The main consideration in the repair methodology is knowing how flooded the area has become. The logistics to allow a long duration repair of more than a week requires the use of floating hotels, small power generators and a pipe mill. Every risk to the employees, especially in a rainforest environment, needs to be mitigated. One of those procedures uses a system called LOGAM/SISCONT, developed by Transpetro, which provides the best fluvial and terrestrial routes to access any point of the ROW and provide registry of all communities and resources in all municipality along the pipeline.
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