Computer Aided Chemical Engineering
Wax deposition problems are an increasingly important research topic in the oil industry, as wells and pipelines become longer and heavier crude oils are explored. Much has been published within pipelines domain but information about such challenge in wells is much scarcer. Wax deposition is due to the cooling process, which occurs when oil flows from the high-pressure reservoir to the surface. Heat loss, with temperature reduction, induces wax crystallization and the subsequent well plugging. This leads to the decrease of well flowrates, and eventually causes the total blockage. One of the goals of this work was to determine wax deposition by applying Aspen HYSYS, as a modelling tool and developing a numerical model in Matlab to face some limitations encountered in Aspen HYSYS. One major accomplishment of the conceived Matlab model was being able to accurately consider internal pipe insulation, the effect of pipe-in-pipe, as well as the underlying geological conditions. Also, two comprehensive engineering solutions, including heating and insulation, were assessed for one oil well with proven wax deposition problems. In conclusion, Aspen HYSYS is highly recommended for most applications since, beyond showing reliable results, is very versatile, user-friendly and has a vast database of worldwide oils’ common properties. However, Aspen HYSYS does not accurately allow esteeming wax precipitation curve, nor the Wax Appearance Temperature, given the oil properties. This is quite a hindrance for wax deposition simulations and leads to the need for experimental data. © 2019 Elsevier B.V.
Year of publication: 2019