Reference Case: Quantitative Risk Assessment at Kashagan Field - Kazakhstan

The Kashagan Field is situated in the northern part of the Caspian Sea close to the Kazakhstan city of Atyrau. Kashagan is the world’s second largest oil field, with estimated commercial reserves of between 9 and 16 billion barrels of oil.

The field is being explored and operated by an international consortium under the North Caspian Sea Production Sharing Agreement. The Agreement is made up of 7 companies consisting of Eni, Shell, Total, ExxonMobil, KazMunayGas, ConocoPhillips and Inpex.

Development of the field is difficult because of the harsh offshore environment, where sea ice is present in winter and temperatures can range from -35 °C in the winter to 40 °C in the summer. More significantly the oil is light with a high gas-oil ratio and a very high hydrogen sulphide (H2S) gas content of about 20%.

H2S is highly toxic and corrosive, and can pose a significant threat to personnel exposed to leaks. This type of environment places increased importance on the accurate assessment of risk, which is a key input to the design and planning of facilities, working patterns and emergency response.

There are a number of off-the-shelf industry solutions for Quantitative Risk Assessment (QRA), however the consortium felt these packages lacked the transparency and flexibility required to more accurately assess the risk for their specific environment.

They therefore decided to go out to tender for the design and development of a bespoke QRA system that would provide them with a more cost-effective, flexible and accurate alternative to an off-the-shelf package.

One of the companies invited to tender was Risktec Solutions, an independent specialist in risk management consulting and training. For this type of complex work Risktec brought Tessella in, an expert in technical modelling and professional software development.

Tessella was immediately able to demonstrate its value by reshaping the requirements. Originally a system based on MS Excel spreadsheets had been specified. Tessella was able to show that the volume of data involved would mean an Excel solution would be error-prone, difficult to maintain and not scalable for use by a large number of users.

A bespoke software solution based around an SQL database was adopted and both Risktec and Tessella were selected to work on the project. An iterative development process ensured the solution met the core requirement of more accurately assessing risk in a high H2S environment.

The innovative new approach to QRA by Risktec and Tessella includes:

- A flexible, transparent and cost-effective way of accurately assessing risk in a high H2S environment, especially compared to standard off-the-shelf QRA packages

- A robust, reliable solution capable of scalable development and easily shared by users in multiple locations

- A professional software development consultancy with proven expertise in technical modelling and algorithm development

- Tailored and consistent QRAs over the lifetime of the field development, enabling higher levels of site and personnel safety through better planning and design of facilities, plant and working patterns

- Ultimately, better informed decisions supporting faster and safer development of the Kashagan field

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