Effect of Gravity on Squeeze Treatment Conference Paper uri icon

abstract

  • Abstract The use of scale-inhibitor squeeze treatments to prevent downhole deposition of carbonate and sulphate scale is a well-stablished procedure in both onshore and offshore oil production facilities. Such treatments are used in production wells when the watercut reaches a level where scale formation is considered to be a problem that cannot be economically controlled by remedial dissolution of the deposits. Increasing the squeeze life is the key parameter in optimizing the treatments. Many ways and solutions for optimization of treatments have been suggested. In this study we are interested in the ways which are related to gravity effects and generally the objective of this project is to investigate the effect of gravity on the different stages of a treatment. INTRODUCTION The formation of inorganic mineral scales within onshore and offshore production facilities around the world is a relatively common problem. Scale can form from a single self-scaling connate or aquifer water, due to changes in temperature and pressure, or when two incompatible waters mix. An example of the latter would be seawater support of the reservoir, where the formation water is rich in cations (Ba, Sr and Ca) and the injection water contains anions (SO4). The production of such commingled fluids results in the formation of inorganic scale deposits. The type of scale and their solubility is a function of the water chemistry and the physical production environment. The use of scale-inhibitor squeeze treatments to prevent downhole deposition of carbonate and sulphate scale is a well-established procedure in onshore, as well as offshore, oil production facilities. Such treatments are used in production wells when the watercut reaches a level where scale formation is considered to be a problem that cannot be economically controlled by remedial dissolution of the deposits. Inhibitor solution injected into the formation has three patterns of behaviour:Some remain in solution. This behaviour has no benefits, because as soon as production resumes, these inhibitor molecules will flow back into the well. So at the start of production there will be a high concentration of inhibitor coming back to surface.Some of the inhibitor is adsorbed onto the rock grain surfaces. When the well returns to production this inhibitor will slowly dissolve into the produced water and hence it takes much more time for it to bring back to the well than inhibitor that remains in solution (above).The third category of inhibitor molecules is those come out of solution and precipitate in the rock as a solid phase. The rate of adsorption and precipitation depends on the temperature of the formation and PH of the solution.

author list (cited authors)

  • Foroushani, S. A., Rostami Ravari, R., & Amani, M.

citation count

  • 0

publication date

  • October 2009

publisher

  • SPE  Publisher