Risk analysis in ultra deep scientific drilling project — A fuzzy synthetic evaluation approach

Exploration of deep earth requires ultra deep drilling attempts on the sea or continent, which is the main goal of scientific drilling projects currently established. Uncertain geological complexity, high requirement for R&D of critical equipment as well as high demand of practical performance has to be encountered during a scientific drilling project, making it full of challenge and risks. Risk management, therefore, is critically proposed for scientific drilling projects in order to reduce the risks. However, many traditional risk assessment methods may not perform well in the project due to lack of high quality data of historical record and sufficient information. This paper, therefore, proposes a fuzzy synthetic evaluation approach for scientific drilling project risk assessment. Four criteria — probability, severity, non-detectability and worsening factor are utilized to evaluate individual and overall risks comprehensively. Linguistic terms instead of numerical values are employed to evaluate each risk normally done by experts. AHP/ANP is used to determine sensible weights of each criterion. Values of risk indices are calculated to represent the level of each risk and the overall risk. Finally, a case study on risk analysis of SinoProbe-09 project conducted in Jilin University is tested to demonstrate the procedure of the method and to validate the proposed method. Results show that the risks of the scientific drilling project can be assessed effectively and efficiently.