While the world is eager to cultivate more sustainable energy sources, it is undeniable that we are still highly dependent on the oil and gas industry. And now, as the global climate crisis intensifies, the industry is facing more challenges than ever before. The processes and systems involved in producing and distributing oil and gas are extremely complex, expensive, and require state-of-the-art technology. Furthermore, these resources are finite and we literally cannot afford to waste a single drop.
Geoscientists working in the industry are constantly facing risks at the subsurface level through engineering, as well as economical risks. The difference between a right decision or analysis and a wrong one could be billions of dollars and extreme environmental damage. In order to maximize the chances of drilling a safe and productive well, large amounts of data about the Earth’s subsurface are gathered and studied before and during the process. One method used in guiding the process is the STOIIP (Stock Tank Barrel Oil Initially In-Place), which is estimated based on both well and seismic datasets with geological and geophysical interpretation. Fundamentally, it is based on the interpretation, analysis, and experience of the interpreter which can result in a great deal of variability. Reaching a STOIIP that is as accurate as possible is extremely important before a company invests billions of dollars in the extraction process.
Hasebe Finds His Niche
Kentaro Hasebe brings a unique depth of understanding to the industry with a strong background in both sedimentology and petrophysics. Although he originally studied volcanology in Japan, he recognized that his job opportunities in the field would be far and few between. He decided to pursue a career in geoscience instead, and took an entry-level position with Japan’s biggest oil and gas company in 2003.
During the next decade, he worked on one of the biggest LNG projects in Indonesia where he basically did all of the work that should be done during the project development phase in one single operator project. He developed his skills in opportunity generation (wildcat well proposition), wellsite/operation geology, variable sample analysis, petrophysical analysis, building the geological model, and even performing the subsurface uncertainty analysis by experimental design method. During this same time, he participated in a variety of American and British field seminars, as well as core workshops, to improve his knowledge of sedimentology and sequence stratigraphy to establish the geological framework of the field.
For oil and gas companies, sequence stratigraphy is the primary tool used to evaluate where an effective reservoir can be developed. It looks at the biostratigraphic correlation, facies and succession in order to build the stratigraphic framework. Sedimentology is then used to understand and identify the facies of an extremely costly core sample, showing a distinct EOD (Environment of Deposition). This is very important information to establish the geological model and oil field development plan. The reality is that only a geoscientist can estimate where the intended reservoir will be most successful.
Since these core samples are so expensive, borehole imaging is often used as a more affordable option. The images have high enough resolution that the processed borehole image shows the sedimentary features, such as sedimentary structure and bioturbation. Thanks to his expertise, Kentaro was eventually assigned as the borehole image interpreter in his company to establish EOD maps. He conducted this specific analysis and interpreted more than 1,000m of borehole images. This is a very complex and challenging task that requires his precise knowledge and understanding across both sedimentology and petrophysics. In fact, he was the very first person in his company to perform this task, which then led to him sharing his experience at the world-wide petrophysical association SPWLA (Society of Petrophysicists and Well Log Analysts,) chapter meeting. His borehole image analysis was so groundbreaking that it is now essentially mandatory to do this interpretation.
Now, what exactly makes this subsurface data so valuable? Considering that a single well generally costs $5-8 million onshore and up to $100-200 million or more in deep water, it is clear that there are massive financial pressures to get it right the first time. In addition, if a miscalculation occurs there are huge risks of environmental contamination or even the triggering of earthquakes.
Since the beginning of his career, Kentaro Hasebe has always had his sights set on improving the extraction process in order to increase profitability and reduce risk. This is what led to his development of the Experimental Design (ED) method for evaluating subsurface uncertainties.
Previously, scientists could utilize either the scenario based approach or the probabilistic approach. However, Kentaro looked to combine these two in order to reduce the number of calculations with optimized design. By adopting the ED method, the geoscientist only needs to calculate around 55 possible cases to capture all of the uncertainty, as opposed to the approximate 729 possible cases through the previous methodology.
Hasebe first utilized this method in an offshore Indonesian project where his company observed an early water breakthrough in the production well which, if left unnoticed, could have cost up to $300 million. To prevent this low-side regret case, he recommended moving the production well to another location – a call that would have been very difficult to make amongst the uncertainty of previous techniques. Similarly, by utilizing this method in an offshore Russian project, he helped his company to save approximately $700 million by proposing two appraisal wells to reduce the subsurface uncertainty before the final investment decision was made.
For Kentaro Hasebe, who first fell in love with geology when he used to hike in the mountains of Japan with his father, this intricate data analysis is his passion. And in this pivotal moment of our planet’s delicate environmental balance, we are incredibly grateful to have people like him in the oil and gas industry – utilizing their expertise to continue to effectively fuel profit while reducing harm as much as possible.