THERMAL SHRINKAGE AND GAS VOIDS FORMATION OF WAXY CRUDE OIL

During the case of emergency or maintenance shutdown, crude oil in the
pipelines undergoes thermal shrinkage and thus, high start-up pressure is needed to
restart the crude flow. Research on thermal shrinkage and gas voids formation will
therefore be helpful in identifying and maybe reducing the start-up pressure. The
objectives of this project are to investigate the effect of cooling rate, Pour Point
Depressant (PPD) and aging process on the gas void’s volume, pressure and
composition. The experiment was carried out by filling the crude oil inside a tube,
heating it up and then cooling it. Few sets of experiments were carried out to analyze the
effect of cooling rate, Pour Point Depressant (PPD) and aging process. The three
parameters of the gas void; volume, pressure and composition were studied and recorded
in the experiments. Based on the results, few conclusions were made. Firstly, the volume
and pressure of the gas void increases with the cooling rate. Next, the presence of PPD
in the crude oil slows down the thermal shrinkage and gas void formation process.
Third, the aging process increases the volume and pressure of the gas void.