The Research And Application Of Wax Removal Technics For Gas-lift Recovery In Nanpu Oilfield

Gas lift production has many advantages such as being suitable for a wide range of well deviation and outcome,relatively smaller footprint for ground equipment and longer period of being free of workover.Artificial island X of Nanpu oilfield,which has been the largest domestic gas lift platform,takes Gas lift the primary artificial lift method because of the narrowness of the island,significant well deviation and complexity of well tracks.The wax content of crude oil on the platform is greater than 10%and paraffin deposition on tubing wall has done seriously damage to production.During gas lift process,wax depositing reduces the oil cross-sectional area and increases flow resistance,leading to a significant decline in well flow rate and damage to economic benefits.Several wax removal technics has been applied on the platform and most were proved to be not adaptive.Artificial mechanical wax removal and thermal washing still remain primary wax removal methods,However,the existing methods are short in wax removal period and heavy in workload,and there are risks such as tool blocking et.Therefore,it is necessary to study on wax deposition regularity in gas lift wells and to build model of wellbore wax precipitation with fully consideration of gas injection.By simulating the wax deposition dynamics in gas lift wells,we can optimize the parameters of paraffin removal and paraffin control technics.The main work of this paper is as follows.(1)Based on a large amount of domestic and abroad studies,the factors affecting wax deposition in gas lift wells are analyzed and the influence of gas injection on wax deposition is considered in the process of analysing.By comparing calculations from different methods to tested wellbore temperature,the calculating method suits gas-lift well is picked.(2)Multiphase flow simulation software OLGA is used to simulate the wax deposition process of gas lift wells,and several factors have been studied such as different models,PI,water cut,gas injection rate and temperature of gas injected(3)Aiming at the defects of paraffin removal and prevention technics in X artificial island of Nanpu oilfield,the optimizations were carried out,and good field application results were obtained.(4)Gas lift technology is optimized for wells of low outcome,and wax control significantly gets better as well as the gas lifting efficiency is promoted by application of plunger gas lift.