Downhole Electrical Heating Dynamic Model Assessment in Faja Extraheavy Oil Reservoir Application
Authors: Velasquez Richard , Lara Victor , Korabelnikov Alexander , Manapov Timur 
Published: July 2020

The "Oficina" formation is the most important in the Eastern Venezuela Basin and represents the main target for this study, which is to optimize the oil production and increase well productivity by the means of reducing the oil viscosity through the application of downhole electrical heating cable. The main objective of this study is to investigate and quantify the effect of downhole electrical heating cable in the performance of the extraheavy oil reservoir and horizontal wells interaction by lowering the oil viscosity applying a coupled reservoir-wellbore simulation approach.

A fully integrated 3D reservoir and discretized mechanistic wellbore simulation approach is carried out in order to estimate downhole heating effect and interaction between reservoir inflow and wellbore performance during the heating inside the wellbore. Bottom hole pressure and temperature profile inside wellbore, productivity index, production fluid rates along horizontal well section are estimated under several sensitivities and optimization process including: heating rate, length and location of the cable inside wellbore. Numerical simulation is performed with commercially available thermal simulation software that has the feature of a wellbore modeling tool that can couple to the reservoir model. Additionally, optimization software is used to perform the sensitivity analysis studies and the automatic optimization of the heating rate, cable length and position.

The heating cable simulation approach allowed understanding the importance of considering wellbore heating parameters and the interaction of the highly viscous extraheavy oil in the reservoir by increasing the temperature inside the wellbore. By applying wellbore calculations coupled to the reservoir simulation, it was possible to understand critical aspects of the oil and gas flow in the reservoir due to different drawdown along horizontal well section, pressure lossess along the wellbore due tor friction and the general efficiency of the heating cable and consequences in oil production.

Bottom hole pressure, productivity index and production fluid rates along horizontal well section, were estimated under several sensitivities and optimization workflow including the heating cable parameters and location inside wellbore in order to estimate the additional cumulative oil production and increase of the productivity index and bottom hole pressure. Therefore, the dynamic model assessment permitted to define several criterias for well selection candidates and founded the basis for wellbore completion design and monitoring protocol program for pilot test in the Field.

Coupling wellbore reservoir simulation is more accurate when compared to a conventional numerical simulation approach since it was possible to conclude that location of the heating in the horizontal section and gas breakthrough could affects negatively the oil production of the wells due to gas expansion inside wellbore with temperature increase. Therefore, it is very important that heating cable assessment consider the fully integrated 3D reservoir and wellbore modeling.