Casabe Field is a mature oil field located in the Mid-Magdalena Valley basin in Colombia, with over 60 than years of production. For the last 25 years it has been waterflooded using a five-spot injection pattern. In 2004 Ecopetrol and Schlumberger initiated a technological alliance aiming to increase the recovery factor and to incorporate new reserves. From an integrated work the project defined an aggressive drilling, completion, workover operations to convert old water injectors into multi-zone selective completion injectors and the abandonment of damaged wells campaign to optimize the waterflooding patterns.
The workover program reached its highest activity peak of from 2008 to 2009. This increment brought the need to perform several well abandonments to avoid interference with the new injector wells. The abandonments also proved to be a main challenge of the campaign because of the well status complexity as severe casing restrictions, fishing, abnormal pressures, and reduced surface location area.
A new methodology to optimize workover resources was developed based on alternating the use of a Coiled Tubing combining a Pulling Unit. This methodology enabled the workover in wells where workover rigs had serious downhole and surface limitations. From 2009, 96 wells were abandoned, 52% of them applying the method that combines both units. The methodology has generated so far 181 days of Workover rig time in savings, therefore allowing the rigs to complete more than 235 wells by the end of 2009, complying with the overall project program contributing with an incremental production of 5000 BOPD. In addition, this methodology to abandon well has generated alone savings of 1.5$MMUSD from the initial CAPEX.
This paper will describe the agile well abandonment methodology combining Coiled Tubing and Pulling Units in a highly efficient, economical way, and complying with HSE standards and regulations allowing its application in any other oilfield.