Ras Budran (R/B) field is located 5Kms. offshore at the eastern coast of the Gulf of Suez and consists of a massive Nubian Sandstone Reservoir compartmentalized by partially major faults. The field is undersaturated and production is maintained by gas lifting while the pressure is supported by a combined water flood and limited aquifer drive.

The R/B produced crude oil has an intermediate base with asphaltene content ranging from 10–15% wt and an average API Gravity 25°.

With the increase in water production and injected seawater breakthrough a very viscous tough emulsion was formed in some wells, causing production problems. Also, due to scale deposition, calcium carbonate and sulphate, the hydrochloric acid and other scale dissolvers were applied to clean the tubing and the formation. Some of these additives have an adverse effect on the emulsion viscosity and cause asphaltene deposition.

The paper presents the study carried out to identify the problem and find a solution for it. The study includes:

  • The rheological properties of the emulsion at different downhole conditions; shear rates, temperatures and water contents at different salinities.

  • The effect of the different chemicals used for scale removal and inhibition on the asphaltene deposition and the produced crude oil emulsion viscosity.

  • The effect of the flow improver products; demulsifier, Asphaltene dispersant, viscosity and drag reducers…etc. on increasing the fluidity and reducing the drop in pressure of the produced crude oil emulsion.

The study results showed that the hydrochloric acid causes asphaltene deposition and tough emulsion formation. Also the increase in the water content form a very tough/viscous emulsion at a certain percentage, which is defined as the inversion point, below and above this percentage the emulsion viscosity is reasonable.

The injection of the flow improver chemicals through the gas lift valves could reduce the emulsion viscosity.

You can access this article if you purchase or spend a download.