Why it is important to drill deeper than the primary objective (ie. the story of "Boffus"). I had the fortune of working the Gulf of Mexico deep-water areas for Ocean Energy some 25 years ago. We participated in many exploration wells, several of which were big discoveries. This is the one that got away. The "Boffus" prospect, which I mapped on TGS 2-dD data is a large four-way closure under 10,000' of salt. Ocean formed a JV with Unocal to drill the first well (Dana Point) to a total depth of 26,850' chasing Miocene sands which are productive some 50 miles north of this prospect. If we would have drilled some 500' deeper than the TD we would have encountered Wilcox section that ended up being the St Malo field.
Back in the Flores & rucks days, they came up with a concept called develocat wells where they would drill a horizontal well through a known productive formation and then dive to see what was below. It was impressive to see them drill these wells in the mid nineties.
Thanks for the post Mike. I think those of us that have been around long enough can relate to ‘if only went deeper back then especially in the GOM. However, as both an exploration prospector and then subsequently management I have to say that I believe that wells should always be drilled to a technically and commercially justifiable target. In my experience deepening wells without doing this, much more often than not wastes scarce exploration dollars that could be spent on more attractive opportunities elsewhere.
Its always been about ranges of uncertainty and ability manage the limits and attendant risks. Too many become fearful of the risks and do not properly credit the upside. In the end, these did not require 20K technology and the real area where true innovation was required for commercial success was in the frac-packs which had a significant learning curve. It is helpful sometimes to consider the fundamentals of the standards and codes underlying the pressure containment equipment, wellheads, trees,and BOP's and how those are qualified for service ratings relative to those upper ranges of pressure uncertainties.
I would imagine that a good interpretation of mud gas isotope data even in the Miocene would have revealed the presence of a deeper more mature charge. Certainly if flourescence was being seen. Handy tool!
That has always been my experience too. If I can get away with it, I always let tbe drillbit go 400 or so feet deeper than the target, especially in new terrain. In exploration one must always leave room for serendipity.
A good lesson for mature field development wells also. Boy, do I have a few stories about this! One that comes to mind - deepening a development well 500 feet in a 37 year old mature field, - because the rig wasn’t ready for completion. The deeper target had been assumed wet for years based on offset fields - it came in at 5000 bopd.
Thanks for sharing, Mike This reminds me of the basic “wildcatter philosophy” that I was introduced to, in my early career: when drilling and encountering pay, keep drilling until you either hit the source rock or the rig can’t physically make hole any longer…. Nowadays, with better seismic imaging, you can couple that philosophy with a probability of encountering a reservoir (based on reflectivity, inversion, regional knowledge) ahead of the bit. Great story. Thanks.
Thanks for sharing, a worthy exploration "cautionary tale." If my memory serves me correctly -- good ol' Geoframe IESX maps/seismic? I was working Deepwater GOM for BP about the same time, then later for Spinnaker Exploration, Norsk Hydro, and Repsol. Very interesting, exciting times + very expensive wells! The last one I was involved with ~2007-08 cost about $157 MM -- subsalt nearly 30k ft MD Wilcox test in KC. Then again, the gross structural closure was around 45,000 acres w/ predrill EUR in the 500 mmboe range 😉
Securing the future of Oil & Gas development!
4moHi Mike, was there an engineering reason that Dana Point ST00BP00 was cut short? Seems like in the early 00's there was still a lot of old iron floating around, maybe 20kpsi BOP's weren't really a thing yet. If I remember right, the Discoverer Spirit drilled the early wells from 2003- 2004 including Dana Point ST00BP02 which cut the Wilcox.