Development of the outside diameter of 244.5mm measurable pressure below valve annulus safe valve

Recently years,annulus safe valve is popularly used as one of the nucleus tools during whole - process underbalanced drilling.In domestic market,the technology is only owned by Weatherford and Keramay Drilling Technology Research Institute of CNPC Xibu Drilling Engineering Company Limited,but it has not the pressure measurement function.In order to improve the annulus safe valve performance and resolve the difficulty of pressure measurement below valve,Drilling Technology Research Institute starts to study the second era valve.The paper primarily introduces the tools structure design,system composition and working principle of outside diameter of 244.5mm valve which can measure the pressure below valves and applies in oil field.