Abstract

In this paper the effects of some metallic oxides used to upgrade the properties of heavy crude oil are discussed. The underlying objective is to increase the mobility of the oil in the reservoir by reducing viscosity and improving the oil quality (e.g. by diminishing the asphaltene and sulfur contents and increasing its ° API gravity) using transition metal supported in alumina and unsupported from transition metals derived from either acetylacetonate or alkylhexanoate in liquid phase homogeneously mixed with heavy crude oil as well as metal transition supported in alumina.

KU-H heavy crude oil from the Golf of Mexico was studied. The API gravity was increased from 12.5 to 21-26, the kinematics viscosity was decreased from 18,130 to 100–8 cSt at 298 K, the asphaltene content was reduced from 26 to 7 wt%, the removed sulfur ranged from 30 to 60%, and the distillable fraction was increased from 20 to 30 wt%; the aforementioned results were obtained by Simulated Distillation and True Boiling Point (TBP).

Introduction

Heavy crude oil can be an enormous source for energy provided the appropriate technology for its production, and processing exists. The availability of cheaper and easier-to-process light crude oil is the key element that has influenced the selection of heavy crude as feedstock. Although in the past, such availability had favored the production of lighter crude, the situation is changing quickly and it could be different in the short term. On the other hand, heavy crude oil and bitumen constitute the 80% (5.6 trillions of barrels) of the worldwide petroleum reserves (1,2). However the main problems that heavy crude oil presents are:

  1. the low mobility through the reservoir due to the high viscosity which affects the index of productivity of the wells,

  2. difficulty in transportation, and

  3. the low capacity of processing in the refineries.

For these reasons, it is fundamental to enhance the heavy crude oil, both aboveground and underground. As for aboveground, several process options have been studied and applied at industrial level to improve the bottom barrel conversion. The main processes are: Thermal Processing(3–5) (delayed coking, fluid coking, flexicoking, visbreaking), Hydroprocessing (6–9) (Fixed-bed, Ebullating Bed, Slurry Phase), and Extractive Processes (10–12) (FW Solvent Deasphalting, Demex). However, all these processes are focused on converting the atmospheric and vacuum oil residues (1000+ ° F) to more valuable products such as gasoline, middle distillates and FCC feed stock. Nevertheless, the hydroconversion of heavy crude oil aboveground has been applied at semi-industrial level because of:

  1. The need of an especial design of either fractionation towers or topping columns,

  2. a high investment due to great hydroprocessing volumes of heavy crude oil required in the refineries,

  3. a high hydrogen and catalysts consumption.

An interesting alternative to the recovery of the heavy and extra-heavy crude oil is the underground hydroconversion. This alternative presents several advantages in comparison with its aboveground counterpart such as:

  1. The increase of the productivity index of the wells,

  2. the reduction of the lifting and transportation costs from de underground to the refining center,

  3. the production of more valuable products due to the viscosity reduction, resins, asphaltens, sulfur, and metal contents by environmentally- accepted processes.

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