Safety Evaluation Of Annular Blowout Preventer

The Annular BOP (Blowout Preventer) is one of the most important equipment in well control equipment. The function is control the pressure of wellhead and keeps people from the blowout accidents, and realizes safe construction. Annular BOP must be equipped with hydraulic control device, and associated with ram blowout preventer, take annular BOP for example, detailed description of the structure.Every element was analyzed, and then the Annular BOP was divided to systems according to their function and got qualitative analysis result of elements included in every system by FMEA. The systems and elements in FMEA analysis sheet were evaluated and quantized by expert scoring method. Faced with severe lack of historical data problem, searched numerous related literature at home and abroad and processed them with appropriate methods.According to the main form of failure occurs to determine the top event and then prepare fault tree. Find out all the fault reasons and their combinations. Summarized fault reasons in several ways and drew conclusions, and made recommendations for improvement targeted.Based on widely calling for experts'advice, this Paper utilizes AHP to determine index weights, gets a evaluating result about navigation safety of elements of Annular BOP by the improved gray- fuzzy model. According to comprehensive evaluation matrix, we calculate gray correlation to determine the importance of the various components.The fault tree analysis and gray-fuzzy evaluation show that rubber core and the hydraulic control circuit are vulnerable to failure, and need to be focus on the detection of protection, we also should be increased research efforts to improve the design.