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In the winter of 2001–2002 BP drilled the Havsule exploration well in 1495m of water offshore Mid-Norway. The efficient and safe drilling of the well was a major challenge due to a series of unknown factors including pore pressure. It was therefore necessary to plan and drill the well with a wide range of outcomes in mind and be prepared to adjust plans during drilling operations. With a particular focus on pore pressure, this paper describes how the well was planned and drilled to account for the uncertainties involved in drilling an exploration wildcat far out in the basin and a long way from any other well. Some of the challenges were:Deepest water well so far in Norway.One of the worst winters in recent years.A gigantic submarine slide 8000 years ago that removed several hundred meters of sediment, increasing the uncertainty concerning pore pressure, fracture and overburden gradients.Uncertainty in the lithology. During well operations there was a high focus on monitoring the pore pressure. Annular pressure and formation pressure were monitored as drilling progressed and pressure prediction models were continuously updated. The results show that careful objective setting, planning, teamwork and implementation can help to achieve results even in difficult conditions with large uncertainties. Introduction The Havsule deepwater well was drilled by BP Norway in 1495m water depth using the Scarabeo 5 dynamically positioned semi-submersible vessel in the Norwegian Sea between November 2001 and March 2002. The objective of the well was to test several seismic features in the Tertiary and Upper Cretaceous which were potentially hydrocarbon bearing, and gather sufficient data to enable complete verification of the prospect. The well was planned and drilled as a rank wildcat. Because of the uncertainties inherent both generally in deepwater exploration and specifically in this well BP assembled a team of formation pressure and wellbore stability specialists which was involved in all phases of the well operation, from the start of planning, throughout the drilling of the well and in the post-well evaluation. The well was originally planned to be spudded and completed in the spring and early summer of 2001, in order to maximise chances of benign weather conditions in what is an extremely exposed area of the Norwegian shelf. However, repeated delays in rig availability resulted in the well being spudded on 1 December 2001, reaching total depth in Feb 2002. Thus it was drilled in winter, through one of the worst weather periods in recent years, and consequently suffered a lot of downtime while waiting on weather.

Petroleum systems (conventional and unconventional) and hydrothermal sedimentary rock-hosted copper, lead-zinc (clastic-dominated and Mississippi Valley-type), and uranium systems can be described in a common system framework comprising the critical processes of (1) establishing the fertility of source(s) of the commodity of interest and the transporting fluid, (2) geodynamic triggers for commodity movement and accumulation, (3) establishing an architecture for fluid movement, (4) accumulation by deposition of the commodity, and (5) preservation. To translate these commodity system models to effective exploration targeting models, they must correspond to business decisions. Exploration is an exercise in scale reduction and has a number of natural business decision points that map to scale: Marrying the systems to the decision points involves identifying (1) constituent processes relevant at each scale, (2) the geology that can map the evidence of the processes occurring, and (3) the data or interpretative products that are best used as spatial proxies to map the evidence and guide area selection at the appropriate scale. A common change in focus is noted across spatial scales for all commodities: in basin selection, fertility is key, with lesser focus on other aspects of the system; in play analysis within a basin, all elements of the mineral system are fully considered; in prospect delineation the focus shifts toward accumulation and preservation. The similarity in the targeting workflow highlights that similar key data sets, tools, and interpretative products are required to assess each mineral system across scale, albeit looking for different features within those products, dependent upon the system being targeted. There are several key differences between mineral and petroleum systems. First, petroleum systems involve a mass trapping process with the transporting fluid as the commodity, whereas mineral systems involve mass scrubbing processes, with the transporting fluid having low concentrations of the commodity, thus requiring much fluid throughput. Second, petroleum systems require the entire system to remain reduced to maintain high-quality hydrocarbon, whereas most copper, lead-zinc, and uranium systems require the systems to remain oxidized until the site of deposition. Consideration of these commodity systems in the context of the Earth’s evolving atmosphere-hydrosphere-biosphere-lithosphere highlights the power of paleotectonic, paleogeographic, and paleoenvironmental reconstructions in the critical step of basin selection. Such consideration also highlights common gaps in understanding the commodity systems. These knowledge gaps constitute high-value research paths that would provide greatest leverage in area selection at the basin and play scales. These include improved knowledge of paleogeographic and paleoenvironmental reconstructions, basin hydrodynamics, and timelines of mass and energy flow through basins. For metal systems, better understanding is required of how metal extraction efficiency, solubility, mineral precipitation, permeability, and pressure and temperature gradients dynamically interact along flow paths during the evolution of basins.

The Gulf of Mexico (GOM) has gone through many waves of exploration and development, each time reinventing and pushing the boundaries. Finally, the realization of crossing boundaries and combining United States and Mexico GOM into "One GOM" commercially and technically is within reach. One GOM resource base - discovered remaining to be produced and prospective - is reaching 50 billion barrels of oil equivalent (BBOE). New plays in the U.S. GOM and the opening of the Mexican GOM, coupled with innovative technological and commercial models and increasing interest from the investment community, are poised to drive value and keep this resource base and production growing further. This manuscript sets the stage for the panel discussion scheduled for 9.30am to 12.00pm, Thursday, May 3, 2018 at the Offshore Technology Conference (OTC). The panelists are oil company executives representing small to large independents and integrated oil companies along with service providers as follows: Tim Duncan, President and CEO, Talos Energy LLC Bjorn Inge Braathen, SVP Exploration, Statoil Niall McCormack, Vice President Exploration, BHP Billiton Petroleum Martin Stauble, Vice President Exploration, Shell Lorna Campbell, Mexico Exploration Manager, ExxonMobil Mark Cizek, Vice President, Williams Stein Rasmussen, Chief Strategy Officer, SBM Offshore Sandeep Khurana, Sr. Manager, Granherne (A KBR Company) and Julie Wilson, Director, Wood Mackenzie

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