Reality, challenges, and perspective of secondary recovery of “Lower U” reservoir in Sacha field - Bloque 60, Ecuador.

Abstract

This document shows the reality, challenges, and prospects for secondary recovery of the “U Inferior” (UI) reservoir in the
Sacha field located on the western flank of the “Central Play” (Sacha-Shushufindi Corridor) in Eastern Ecuador. The history
of production began in 1972 with the drilling of wells and years later with secondary recovery projects, achieving an increase
in oil production. The UI sandstone is one of the main producing reservoirs in the field; it stands out for its high volume of 3P
reserves and the present opportunity to recover it in the medium term, without this being the only producing reservoir with
secondary recovery. The reality of the field shows that the interventions in the producing areas and the application of production
optimization techniques such as hydraulic fracturing, commingled production, matrix stimulation, change of zones, and drilling,
among others, have been limited by the low pressures in the reservoirs of the Napo formation; which are depleted and with
the presence of free gas. For this reason, additional challenges are generated in different evaluated scenarios of production
increases, for the handling of fluids, and traditional artificial lift systems. The challenge is to look for the development of the field
under these conditions, using simulation applying the Buckley-Leveret method and implementing additional projects to recover
the pressure of the UI sandstone defining injection arrangements and repowering of existing facilities (currently limited), thus
managing to expose the ideal cases adjusted to reality and show the increase in the volume of accumulated production of the field
under certain perspectives in favor of the interests of the country.