Study and application of a novel neutral scale removing/inhibiting agent for gas well

Aiming at the problem that wellbore blockage slowly induced by water production in the gas field of lower palaeozoic in Sulige, and the decrease of production in some wells caused by this, the reasons of wellbore blockage were analyzed. Through the analysis of the blocking components by the instruments in laboratory, a neutral scale removing/inhibiting agent was developed to reduce well tubular corrosion caused by fluids and to extend maintenance cycle. The indoor evaluation experiments show that the dissolution rate of plug of the agent can reach 95% in 16 hours, while the corrosion rate is very low. The inhibition rate can achieve 80% or above for different types of inorganic scale when the dosage is 40 mg/L, and then the wellbore scaling cycle can be delayed. The product was applied to 3 wells, and the wellbore blockage was removed with daily gas production of average single well improving 213.3%. The application of this technology meets the need of late stage exploitation of gas field with safety, speed, and efficiency. The trend of cost efficiency development of gas field also provide guidance for the advancement of competing technologies.