Reactivation of wells through reentries with a horizontal section in unconsolidated heavy oil sands

The current exploitation areas of heavy oil are located in southern Monagas and have an estimated STOOIP of 26.5 MMMBLs. The production mechanisms are bottom water drive and rock expansion. Cumulative production reaches 685 million barrels up to July 1994. In order to optimize the exploitation of the heavy and extra heavy oil remaining reserves by lowering the pressure drop between reservoir and the wellbore, reduce costs to increase the profits from these reservoirs, a program of horizontal redrill or {open_quotes}reentries,{close_quotes} as known widely, was started. This paper presents the experiences and results obtained after 41 horizontal reentries made in Jobo, Pilon, and Morichal Fields in the period April 1993 to July 1994. Up to July 1994 wells were active with an associated of 21.7 MBOPD with an average of 20% water cut, confirming the successful application of this technology in heavy oils and unconsolidated sands. Several points will be discussed such as reservoir characteristics, well design, horizontal length, productivity index, drilling, completion, water production, surface equipment, and production of horizontal wells compared with vertical wells.