The Use of mCSEM for Deep-Water Hydrocarbon Exploration in Brazil


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About the Course

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2013 SEG Honorary Lecturer. During the past nine years, several operators have gained experience in marine controlled-source electromagnetics (mCSEM) through many multiclient and proprietary surveys in all major oil provinces of the deep-water Brazilian offshore. This has been part of the enormous industry interest that resulted in the increasing application of mCSEM around the world to map resistive features, potentially related to hydrocarbon accumulations, beneath the ocean bottom. The technology has matured significantly since its initial applications due to rapid instruments development, fit-for-purpose vessel operations, wide-azimuth 3D acquisition, advances in 3D anisotropic depth imaging, and novel integrated interpretation workflows. Today's success rate is much higher than in those early days, and this success is in part due to the application and development of the technology in the Brazilian offshore.

This lecture overviews the application and development of mCSEM in Brazil, focusing on the Petrobras experience and contribution. As an early adopter, Petrobras has played a significant role in technology development with major contributions in the areas of new survey acquisition design, processing and imaging products, new inversion concepts, new integrated interpretation workflows for prospect maturation, risking, and resource estimation in order to extract full value from the data. Petrobras has acquired a large amount of mCSEM data since 2005 as part of its deep-water exploration program and it is at the forefront in addressing specific challenges and new applications specifically in the areas of reservoir characterization and monitoring. Specific case studies will demonstrate good practices, successes, and pitfall in several deep-water Brazil scenarios. The lecture will conclude with a "look ahead" toward integrated mCSEM for appraisal and development.

Your Instructor

Marco Polo P. Buonora, PhD, SEG-HL
Marco Polo P. Buonora, PhD, SEG-HL

Marco Polo Pereira Buonora is the manager of Non-Seismic Geophysics at Petrobras, in Rio de Janeiro, Brazil. He is responsible for the acquisition, processing and interpretation of all non-seismic data – gravity, magnetic and EM methods, particularly marine controlled-source electromagnetics (mCSEM). He has been based in Rio de Janeiro since 1969. He earned a BS in geology in Recife, Pernambuco, Brazil, and began his career as a geologist at the Brazilian Ministry of Mines and Energy, working with gravity and magnetics data acquisition and interpretation, and later worked for a mining company looking for base metals and gemstones, and as a geophysicist in a service company focused on acquisition, processing and interpretation of airborne-magnetics and gammaspectromety data. In mid July 1974, he was granted a Fulbright scholarship and went to St. Louis University where he earned master's and PhD degrees in geophysics, with emphasis on gravity and magnetics. After returning to Brazil in 1980, he joined Petrobras where he has been active in gravity and magnetic interpretation of several onshore and offshore sedimentary basins in Brazil. He has worked in the areas of vertical seismic profiling, both on land and offshore, and nuclear magnetic resonance. In the last ten years, he has been involved with the acquisition, processing, and interpretation of mCSEM. He is also a part-time associate professor at the University Federal Fluminense in Niteroi, Rio de Janeiro, Brazil, where he teaches applied gravity, magnetics, digital signal analysis, and inversion of geophysical data. He is a member of the Brazilian Geophysical Society, serving as president in 1989-1991, and of SEG and EAGE.

Interview with Dr. Buonora

Please tell us a little bit about yourself. (e.g. your education and work experience, why you became a geophysicist, etc.)

My interest in applied geophysics began when I was an undergraduate working toward a degree in geology at Recife, Pernambuco, Brazil. I decided to be a geophysicist, with a focus on mining exploration. Once the BS degree was granted, I moved to Rio de Janeiro to work as a geologist at the Brazilian Ministry of Mines and Energy (DNPM and later at CPRM) where I was involved with gravity and magnetics data acquisition and interpretation. During this period, my desire to become a geophysicist increased enormously because I learned a lot of magnetic data acquisition and interpretation from Donald Hoover, a USGS geophysicist (now retired and still a good friend) at the Ministry of Mines and Energy, through a cooperative agreement between Brazil and the USA. After two years of extensive study and hard work, I went to work for a mining prospecting company, looking for base metals and gemstones. I later joined a company which performed airborne magnetics and gammaspectrometry data acquisition, where my task was to process and interpret the data.

During all the time I was working with those companies, I felt I needed a formal background in geophysics, i.e., at least a master's degree in geophysics. Then, trying to pursue that goal, I was granted, after a worldwide entrance examination, a Fulbright scholarship which paved my way to go to Saint Louis University where I earned master's and PhD degrees in geophysics, with emphasis in gravity and magnetics. Despite being offered a job to stay in the United States with a major oil company, I decided to return to Brazil. I got a job with Petrobras, the Brazilian oil company, in early 1980, and I am now the manager of Non-Seismic Geophysics.

In addition, I am also a part-time associate professor at the University Federal Fluminense, in Niteroi, Rio de Janeiro, Brazil, where I teach applied gravity, magnetic, digital signal analysis, and inversion of geophysical data.

Would you like to mention anything about your personal attributes that helped you achieve the professional status you enjoy today; was it self-belief, hard work, a mentor, or something else?

I believe it was a mixture of self-belief and hard work, greatly helped by my understanding that applied science has to be founded on a solid knowledge about the fundamental physical principles linking the physical properties of rocks to geophysical methods (gravity, magnetics, electromagnetics, seismic, etc.). In addition, I never liked to take a "No" in answer to a question, without a convincing explanation why not to do something or to go ahead! Because of that, I believe I have managed to, on several occasions, change the status of some well-established positions.

Why did you choose this lecture topic? Why is it important?

Because I believe mCSEM (marine controlled-source electromagnetics) has shown to be an important auxiliary geophysical method for seismic interpreters, in helping mitigate the risks of false negative anomalies interpreted from some well established DHI (direct hydrocarbon indicator), such as AVO, in such a way as to provide a prospect de-risking assessment. In addition, provided there is already an oil discovery and the proper environment conditions for the application of mCSEM, this technique helps the mapping of the lateral extension of the target reservoir, and, hopefully, it also may help to delineate its vertical distribution, through the utilization of a well-tuned joint 2.5D and 3D mCSEM and seismic inversions. It is also important in building a velocity model for some complex salt scenarios, especially in mapping the base of allochthonous bodies. I will show that a combined inversion of seismic data with mCSEM and MT data increases the accuracy in determining the base of salt.

Could you tell us in a few sentences what your course objectives are?

The main objective of my lecture is to show the importance of the application of mCSEM in prospect de-risking, mapping bypassed oil zones, prospect appraisal , and evaluation through real case histories. In addition, I will address the workflow within Petrobras to attain those objectives.

What do you hope people will have learned after they attend your lecture? How is it different from other lectures?

The message I intend to leave is that integration is the name of the game! That is, using other physical rock parameters such as resistivity, where the mCSEM is highly sensitive, together with seismic attributes. So integration means the combined use of seismic with mCSEM and that this has shown its value to Petrobras within the exploration workflow.

You have quite a busy year ahead. Do you enjoy traveling? Will it be difficult to balance the tour with your work?

Yes, I enjoy traveling and it will not be difficult to balance it with my work.

Would you share with us one or two of your most exciting successes?

It was to build, within Petrobras, a group of young geophysicists completely dedicated to the development and application of non-seismic geophysics (gravity, magnetic and electromagnetic), especially one subgroup entirely dedicated to EM methods. With such highly dedicated geophysicists, we were able to achieve at Petrobras recognition of the value of mCSEM and, consequently, the company sponsored the largest mCSEM data acquisition ever acquired offshore Brazil. The result of this survey forms the basis of my presentations during my 2013 Central and South America Honorary Lecture.

How about a couple of disappointments?

It was the lack of understanding of one of my previous directors of exploration, while I was working with the Ministry of Mines and Energy, who felt that providing an advanced education for those who wanted to pursue a master's degree in geosciences was a kind of nonsense! Fortunately, this kind of person is no longer working for the government.

What advice would you give to geophysics students and professionals just starting out in the industry?

Keep updated with the development and advancement of geophysics as applied to the oil industry, keep studying vigorously and continuously, never give up your beliefs, be truthful/frank with your partners, managers and co-workers.