Prevention of formation and negative influence of persistent water-in-oil emulsions by sucker rod well pumping units
- Almetyevsk State Oil Institute
Abstract
Water encroachment of well products at late stages of oil field development leads to formation of oil-in-water emulsion. At water cut of 30-80% three-component emulsions are formed, which lead to rod sticking and, eventually, to rod string breakage. Water-in-oil emulsions differ from crude oil in both viscosity and initial shear stress. The increase in viscosity of water-in-oil emulsions when the rods are mechanically actuated occurs approximately in the first third of the lift string, starting at the pump. At further lifting the viscosity of the mixture increases not so intensively, and its growth is due to the decrease in temperature and pressure during the ascent to the wellhead. In the work measures are proposed to reduce the hydrodynamic resistance to rod movement at load reduction.