Analysis and application of cleaning tool structure in negative pressure reverse circulating wellbore

Abstract

Sediments frequently appear at the bottom of oil and gas wells in the bottom of carbonate rocks during completion or production, seriously affecting the productivity. In order to solve the wellbore cleaning problem, this article applies the Bernoulli equation theory method, the finite element method based on the standard turbulence model and the laboratory test to verify a kind of negative pressure wellbore cleaning tool which can establish local reverse circulation under the action of high-pressure water jet and salvage the bottom debris. Through the numerical analysis of the cleaning tool structure, it is found that the wall face diameter is at least two times of the nozzle hole diameter to effectively play the cleaning tool performance. If the total area of nozzle outlet is 48π mm 2 , the cleaning tool fishing capacity of six nozzle structures is improved the most. The analysis of the adaptability of the cleaning tool shows that the cleaning tool with an outer diameter of 104 mm is most suitable for the casing shaft with an inner diameter of 127.3 mm. The cleaning tool was applied to the field operation and successfully cleaned the wellbore, effectively increasing the wellbore productivity.