Managing Marine Geohazard Risks Throughout the Business Cycle
Authors: Wilson Adam 
Published: July 2016

This article, written by Special Publications Editor Adam Wilson, contains highlights of paper SPE 173139, “Managing Marine Geohazard Risks Over the Full Business Cycle,” by Andrew W. Hill and Gareth A. Wood, BP America, prepared for the 2015 SPE/IADC Drilling Conference and Exhibition, London, 17–19 March. The paper has not been peer reviewed.

Today, the industry is faced with entry into frontier areas with little prior published understanding and potentially complex slope and deepwater settings. In such settings, early effort in the explorationand- production cycle is required to allow appropriate data to be gathered and assessed. In order to address these issues, BP has adopted a methodology to manage geohazard risks over the life of the license.

Introduction

In 1964, the rig C.P. Baker was lost in the Gulf of Mexico in a shallow-gas blowout with the loss of 22 lives. That accident, and similar events in the industry around the same time, triggered the development of geophysical site investigation or geohazard methodologies to support safety in tophole drilling and field development through detailed assessment of seabed and near-surface geology. To this end, the Hazards Survey in North America and the Site Survey in Europe became the staple means for evaluating predrill or predevelopment conditions over the following 30 years.

The technologies used in these surveys have continued to be developed. These approaches have generally served the industry well for 50 years. However, as the industry has progressed from operations generally on the continental shelf out onto the continental slope and into ultradeep water, the geohazard issues that need to be addressed by the industry have grown in variety and complexity.

While the scope of possible sources of geohazards has expanded, so has the potential size of license areas to be studied.

If conditions across such blocks on the continental shelf or in ultradeep water were homogeneous, it may be acceptable to continue with the traditional approach of the site survey. However, the conditions in many large blocks are far from homogeneous, and, therefore, a site survey would deliver little understanding of the variability in geohazard conditions and processes that may have implications for the immediate safety of drilling.

The longevity of production operations now faced in a license or field has also been gradually extended through the implementation of improvedrecovery techniques. BP’s Magnus field was discovered in the far north of the UK continental shelf in 1974. At the time of first oil in 1983, the projected field life was seen as being out to the mid- 1990s. However, another phase of production drilling will be starting from the platform in 2015, and current projected field life is now seen out to the 2020s. However, the last high-resolution seismic data to have been acquired below the platform were acquired in 1984. Before restarting drilling, a prudent operator would ask the question, “What is the possibility that geohazard conditions may have changed over the last 30 years?” The prudent operator, therefore, needs to revisit geohazard risks and the validity of site-investigation data across the full life of the license, from entry to field abandonment, and to update geohazard understanding consistently across the whole time period.

This paper, therefore, sets out an integrated approach to address management of geohazard risks across the life of a license (Fig. 1), an approach that seeks to consistently update understanding of what geohazards might be present, and, thus, where possible, seeks to avoid them directly or mitigate their presence.