At a time when the demand for energy is growing in Argentina, operators are seeking to improve the profitability of unconventional oilfields by drilling wells with longer lateral lengths (up to 3200 meter), allowing a larger area to be drained by single wellbore, minimizing overall development cost.
This paper outlines methods and resources used to drill this long lateral well along with the limitations that arose during the planning and execution phase.
Currently the development of the unconventional oilfield in the Loma Campana and El Orejano oil areas are established with wellbore design of 3 casing strings, drilling the production zone (Vaca Muerta) in an open hole of 6-1/8" and completing it with 5" casing; achieving horizontal lengths between 2400 m to 2600 m with a maximum of 2715 m.
The current configuration of these types of wells is in a technical limit stage, due to the maximum hydraulic power that the available drilling equipment possesses and the loss of efficiency with its consequent increase in costs in the completion stage. It is for this reason and looking to increase the number of fracture stages per well, that the construction of a well of robust architecture and greater extension was considered.
The design change contemplated 3 casing of higher diameters 13 3/8," 9 5/8" and production section in 5 ½". This design requires drilling production open hole section in 8-½" diameter. This allowed to increase the lateral length to 3200 m, avoided reaching the hydraulic power limit of the drilling equipment and maintained the same design of stimulation while preserving the efficiency.
The presentation of the paper consists of the technical feasibility analysis, contemplating the uncertainties regarding drilling fluid hydraulic behavior, torque & drag, the operational results of the experience, and the resulting cost analysis.