17th September 2019
Food and drink served from 6:00pm, lecture starts at 6:30pm
PESGB Members do not need to register to attend
In 2015, the Oil and Gas Authority (OGA) fully embarked on implementing the recommendations set out in the Wood Report, including a re-assessment of Yet-to-Find (YtF), and performance tracking of exploration wells. This presentation will discuss the revised YtF estimate published in 2018, and what measures the OGA has undertaken not only to improve the assessment, but to start to use it to steward and promote activity in the UKCS.
The YtF process is summarised in Figure 1. Much of the work has been based on techniques developed and published by consultants Rose & Associates, including for the first time an estimation of volumes lying outside of the Prospect Inventory (PI). Within the PI, calibration with historical success-rates and field-size distributions has brought estimates into line with ongoing drilling performance. The PI has been maintained on behalf of the OGA and its predecessors by the British Geological Survey (BGS), who historically mapped many of the features. In more recent times, data from industry’s bid applications has been utilised to populate the PI. The OGA is currently working to improve the structure and quality of the PI via its stewardship process, including via the annual Survey, pre-drill and post-drill assessments, and review meetings. In future, the OGA will work to “close the loop” by gathering structured data at the licence relinquishment stage, and as a first step has developed an initial dataset of opportunities for publication alongside the 32nd Offshore Licensing Round.
Figure 1. Flow-diagram summarising the process used to estimate Yet-to-Find potential.
Separation of the PI into Trap Concepts, Leads, Prospects, and Drill-ready Prospects has also allowed the distribution and progression of resources to be investigated, and the process of prospect creation and re-cycling to be more fully understood. The current “resource funnel” is shown in Figure 2. It is apparent that only a relatively small number of drill-ready prospects are available, sufficient for two to -three years drilling activity, and requiring active prospect generation and maturation within industry to ensure activity beyond that point. As a consequence, prospect generation and maturation to drill-ready status, is currently a key focus for the OGA.
Figure 2. Prospective Resource Maturation Funnel showing the Mean Yet-to-Find Resources in the UKCS’s producing basins, split by Resource Category. Coloured Circle Areas are proportional to the mean risked prospective resource (value in top right of each category box). Inner Dashed Circle Areas are proportional to the resource after cut-offs are applied (Volume in brackets represents viable features after cut-off has been applied). The number of lead/prospect features, n, is shown in the bottom right of each category box (number after cut-off shown in brackets).
The OGA has been building a comprehensive dataset of pre- and post-drill assessments since 2015 that allows “performance tracking” by comparison of predicted versus actual results. Results are consistent with many published examples from around the world with success-rates being estimated fairly closely, and success-case volumes suffering from over-estimation. By using the same calibration techniques developed for the YtF, the OGA has been able to correct the over-estimation bias, primarily by reducing the P99 estimates at a prospect level, and this will be illustrated with a number of diagnostic plots.
Finally, the presentation focus will move to the OGA’s view of future activity, where opportunities can be found, how supporting information can be accessed, together with an update on the latest OGA news.