Blind Alleys in Exploration, Part II
From the President: Jon Blickwede
In my column last month, I made the point that the petroleum exploration process should at times involve going down some blind alleys. In the case of a new exploration play, the technical and commercial risks are especially high. But the world would have run out of oil and gas long ago if it weren’t for companies, and individuals, willing to take on a high level of risk. I described a moment in my career when an exploration manager was unwilling to accept the risks of deepening a wildcat beyond the main reservoir target, missing the opportunity of possibly opening up a new play. This month, I recall a different and more positive experience – where a manager was not only willing to accept a high level of risk, but actively encouraged the technical staff to use their geological imagination and bring forward new and bold ideas.
It was 1983, when I only had a couple of years of industry experience under my belt. I was working in a Gulf of Mexico regional team and was assigned a project to study the structural styles of the offshore Texas continental shelf, where some sizeable natural gas discoveries had been made in recent years, most notably by Shell in the so-called Corsair Trend. To evaluate the area in its basinal context, the seismic data set I selected included the 1970’s-vintage 2D survey acquired by the University of Texas at Austin – the first seismic survey ever to cover the entire offshore Gulf of Mexico. One of the UT lines started on the inner Texas shelf and stretched a few hundred miles across the Gulf to the Yucatan Platform. During my presentation to the manager, in which I was talking about the minutiae of the different growth fault systems of the Texas shelf, I laid out a paper copy of the interpreted line on the long conference room table. The shelf portion of the line was located on one end, but the manager kept interrupting me, pointing at some huge anticlines on the continental rise on the central part of the line, and asking “what’s that?”. “That” turned out to be the massive compressional folds of the Perdido Foldbelt, which were some 200 miles from the nearest well control and located in 7,000-10,000 feet water depth. The size of the anticlines was hard to ignore, but at the time the area wasn’t on most companies’ radar because of the extreme water depths. After the presentation, my supervisor told me that the exploration manager requested that we start a new project on the geology and hydrocarbon potential of the Perdido Foldbelt. It turned out that apart from the couple of UT lines crossing the trend, some seismic contractors had acquired a grid of widely-spaced 2D lines, so I proceeded to map the US portion of the foldbelt and was able to create a rough structure contour map of a prominent reflector (which later turned out to be the top of the Cretaceous). Many large anticlines were revealed, and if any of these contained significant potential reservoirs and were hydrocarbon-charged, the preliminary resource estimates were of giant or even supergiant magnitude. But the challenges were considered by some to be insurmountable. One memorable event during this period was the first time that I presented the Perdido play to the company’s drilling and production engineers, who I needed to help put together some initial “scoping” economics. When the engineers first learned of the water depths, they actually laughed. The ensuing results of the economic analysis were indeed sobering, but nevertheless the exploration manager encouraged us to proceed with the project. Eventually more seismic was acquired and interpreted, along with a drop core survey in 1986 that recovered visible oil in a few samples. Those documented oil seeps, more than anything else, convinced my company and a few others to bid for the first time on OCS blocks in the area. The first wildcat in the trend, Baha-1, wasn’t drilled until a decade later, and the first commercial discovery, Great White-1, wasn’t made until 2001. Since then, the Perdido Foldbelt has seen additional discoveries on both the US and Mexican sides of the trend. So for me, it serves as a great example of the importance to the exploration process of geologic imagination, optimism, persistence, and a willingness to sometimes follow hunches down blind alleys.
I’d like to wish all the best to the incoming 2020-2021 HGS Board, who will take the reins on July 1st. It may be a more challenging time than normal, but I have full confidence that your new Board will meet those challenges.
Never stop exploring!