The Electric Submersible Pump (ESP) intake pressure and well bottom-hole pressure are important factors in reservoir management and well performance optimization. Normally, the bottom-hole pressures for ESP wells are determined by ESP sensors, slick line pressure gradient technique or acoustic sounding technique. However, there're still some wells' ESPs have no sensor (or sensor failed); and acoustic or slick line operations can't be run due to the well bore restrictions.
This paper develops a method of measuring bottom-hole static and flowing pressure by variable ESP speed for these wells. And it is a quick way to get the pressure data without shut-in operation and can be operated at low cost. The theory of the method is the "Affinity Laws" of centrifugal pump. The centrifugal pump heads will change as the square of speed variation. And with a deadhead test under different ESP speed conditions, the bottom-hole pressure can be calculated.
There are around 80 ESP artificial lift wells in the case field at Bohai bay. All of these wells produce with ESP and sensor installed. However around 13% sensors are failed due to misc. reasons. Reservoir management became complicated because unable to get the exact reservoir pressures.
By the method given by paper, after the authors get the deadhead pressure data, comparison has been done with sensors had reading pressure in 12 wells. Authors also tested 11 sensor failed wells' downhole pressure and successfully optimized wells' performance.