The high levels of CO2 in the pre-salt reservoirs posed a new challenge for collection systems using flexible pipes: stress corrosion cracking by CO2. Depending on the material, voltage levels, CO2 contents and the flooding of the annular region of the pipeline, conditions are created for the occurrence of this mechanism, which may lead to a reduction in the pipeline's useful life.
"In response to this challenge, unprecedented in the industry, Petrobras created a broad integrity program, involving academia, suppliers, market, partners and other stakeholders, with a strong technological pillar, which introduced new systems, methodologies and technologies for the management of integrity and has been making available new pipeline solutions”, informs the Director of Production Development, Joao Henrique Rittershaussen.
With strong involvement of the Petrobras Research Center, Cenpes, and in partnership with several companies in the market, new tools were made available to identify the presence of water in the annular space of flexible pipes, information that is essential for managing the integrity of these pipes , providing greater operational safety and guaranteeing the useful life of these structures. The pipelines connect the subsea installations to the oil production platforms and the presence of water between the layers of these structures can lead to corrosion of the metallic layers. The use of inspection technologies brought an estimated gain of around $1 billion in 18 months.
By being able to identify the presence of water in the annular of the pipelines in operation, the tools prevent the disassembly and reconnection of the pipelines, reducing costs with naval resources, as well as avoiding oil production losses due to stoppages for these operations. The company is the largest user of flexible pipelines in the oil and gas industry worldwide and almost all offshore production is transported through them.
“We are seeing the results of accelerating the company's innovation journey, bringing more safety and efficiency to the business activities. Our teams are committed to developing, internally or through partnerships, new products and solutions that generate value deliveries for Petrobras”, says the director of Digital Transformation and Innovation, Nicolás Simone.
The inspection tools have been used in the pre-salt fields, especially in the oil production and gas injection pipelines on the platforms of the Santos, Búzios and Libra business units and use different methods to detect the presence of water in the pipelines. In addition to the solutions available on the market, Petrobras has carried out internal developments, such as the MD-Seal tool, which is capable of measuring the internal pressure of the pipeline through a valve. The result indicates the presence or not of the liquid. Another tool, called Collector Ring, identifies the existence of water by means of ultrasound in the connector. Sound propagation changes depending on the absence or presence of water in specific regions.
The tools of companies in the market also use the principle of ultrasound, and inspection takes place through the tubular body of the ducts. Some of these companies use Artificial Intelligence, capable of “seeing” details beyond the human eye's capacity, to interpret the collected data.
The need to develop and use different techniques for detecting the presence of water is due to the diversity of flexible pipeline models on the market for different uses, gas injection or oil production, and the installation configurations, such as flowlines, the ducts seated on the seabed, and the risers, the ducts that connect the flowlines to the production platforms.
In addition to qualifying and validating tools available on the market, Petrobras encourages experimentation and innovation through terms of cooperation with science and technology institutions (ICTs), such as universities. The MDSeal tool, for example, was developed with the Federal University of Rio Grande do Sul and Senai.