Synthesis of Wax Inhibitor and Assessment of Squeeze Technique Application for Malaysian Waxy Crude

Abstract

Highly paraffinic (or waxy) crude oil can cause significant problems in the pipelines due to wax–oil gel blockage resulting from the precipitation of the wax components. Once blockage of the pipeline occurs and flow ceases, the pipeline flow cannot be restarted with the original steady state operating pressure but instead requires significantly higher pressures to restart the flow. Due to this, it is important to maintain the oil at a temperature above its natural pour point. The incorporation of chemical products known as wax inhibitors and pour point depressant (PPD) reduce the pour point and viscosity of oil. This paper introduces an indigenously synthesized wax inhibitor from the hydrophobically modified polybetaines (zwitterionic) family for treating waxy crude A located in Peninsular Malaysia. The synthesized wax inhibitor had been evaluated as flow improver, crystal modifier and pour point depressant. The wax inhibitor coded CRODDA-AA, works efficiently since it can reduce the pour point of waxy crude A by 12°C and the viscosity about half of the original value at 1000 ppm concentration, as well as lowering the yield stress by 8 Pa at 51°C. In order to assess the use of the CRODDA-AA wax inhibitor for squeeze applications, a core flood study was conducted to determine its adsorption capability onto formation. A formation damage study was also conducted to ensure that there is no formation damage coupled with the injection of wax inhibitor. It was found that wax inhibitor CRODDA-AA can be retained in the formation up to 88.5% without significant formation damage. As a next step, it is planned to run the core flood and wax inhibitor release tests to refine the design of squeeze treatment.

A Critical Review of Controlling Paraffin Deposition in Production Lines Using Chemicals

“…Hence, it is critical to predict the gelation temperature during the pipeline shut-in process when the fluid might be cooled below the pour point. Several manual and automatic methods can be used to measure the pour point, such as ASTM D97, ASTM D5853, , and rheological mechanical spectrometer (RMS) . Both wax inhibitors and PPDs are able to lower the pour point and viscosity. ,,− The efficiency increases with increasing concentration and reaches a plateau.…”

Synthetic and natural polyampholytes: Structural and behavioral similarity

“…Application of hydrophobically modified and acrylamide‐based polyampholytes in EOR has been reviewed 52,70 . Hydrophobically modified polyampholytes have been shown to act as efficient pour‐point depressants and for alkaline‐surfactant‐polymer flooding 71‐75 . According to Gou et al, 76 additional oil recovery, equal to 15.46%, has been achieved utilizing hydrophobically modified polyampholytes based on acrylamide, sodium acrylate, 3‐(diallylamino)‐2‐hydroxypropyl sulfonate, and 3‐(2‐[2‐heptadec‐8‐enyl‐4,5‐dihydro‐imidazol‐1‐yl]ethyl‐carbomoyl)acrylic acid.…”

Recent advances on mitigating wax problem using polymeric wax crystal modifier

“…While, for yield stress reduction, the best formulation was obtained when it was dissolved in o-xylene, approximately seven times yield stress could be reduced in comparison with crude oil itself. The performance of this polymer for a Malaysian waxy crude was systematically evaluated by Halim et al (2011). As a conclusion, 1,000 ppm is the optimum dosage.…”