EFFECTS OF DRILLING MUD CONTAMINATION ON THE PROPERTIES OF WAXY CRUDE OIL

Abstract

Contamination of crude oil with drilling mud normally occurs during drilling process. The contamination may change the properties of crude oil leading to inaccurate assessment of the first extracted crude oil. Incorrect prediction of crude oil properties and behavior will subsequently lead to under- or over-designing of the upstream and midstream facilities. Therefore, the work aims to investigate the effects of drilling mud contamination on waxy crude oil properties such as pour point temperature, wax appearance temperature (WAT) and the yield strength of the waxy crude oil gel. Measurements conducted on the drilling mud contaminated mixture show no effect on the pour point, minimal changes to the WAT and considerable increase to the viscosity and yield stress values. Bottle test results indicate that drilling mud free oil layer which should be used in characterizing the crude oil exist only after 24 hours of gravity settling.

Keywords

• drilling mud contamination
• waxy crude oil properties
• yield stress