Production Optimization of Oil Wells (Problem of Salt Deposit)

Abstract

The Hassi R'mel field is a gas condensale reservoir with a rather significant oil rim on the eastern and southern peripheries. Producing wells were drilled to develop the oil zone. Unfortunately, these wells were confronted by a severe salt deposit problem, more or less related to the exploitation regime, which severely reduced oil production or caused the well to be shut in totally. The presence of sodium chloride inorganic precipitate in the well is undoubtedly influenced by: ○ The type and quantity of waler influx; ○ Operating procedures; and, ○ Reservoir characterislics, such as temperature and pressure A permanent fresh water injection under a packer did not it prove the performance of these wells. A large volume of water injection is required for particular wells, which has meant that the rapid salt deposition needed a daily coil tubing intervention This treatment tends to become a cost factor and these wells are then shut in. A study was undertaken in collaboration with the Research and Development Centre (CRD) at Sonatracli to solve the salt deposit problem in production due to the effect of temperature change. It consists of analysing a sample of the formation water in order to understand the phenomenon of the salt deposit, to test the anti-deposition product efficiency, and 10 optimize its concentration under surface and bottom conditions, keeping in mind the reduction of the amount of injection water. Laboratory testing was undertaken first of all, in order to assess chemical water in jection compatibility with formation water to ensure that the two fluids will not produce precipitates. It has shown that the alkyl amide aqueous solution is used to prevent precipitation of sodium chloride crystals from high chloride brines from the bottom of the hole, changing crystal growth from symmetrical cubic orientation to a non-symmetrical dentritic type. Independeiuly of the temperature, its efficiency will also depend on the presence of other salts in the brine and the pH. The purpose of this paper is to show: I. The problem created by sodium chlorite salt deposits which impede the performance of a well; and. 2. Solutions adopted to improve the Productivity Index, by using chemicals to reduce deposits of salt.