Surveillance Using Dimensionless Variables in the Mature Oil Field La Cira Infantas

Abstract

La Cira Infantas is the oldest oil field in Colombia. It has approximately 100 years of production, and it is located in the Middle Magdalena Valley Basin, producing from a black oil multilayered and heterogeneous sandstone reservoir. Primary production began in 1918 until 1959 when the first water flooding process began. In 2005, Oxy Colombia and Ecopetrol initiated a joint venture of a new redeveloped water flooding process. Since the joint venture, the field has expanded to 400 patterns and 1,000 active producer wells, 95% of which are under a water flooding process. The redesign of the field considers 20-acre to 25-acre on average and 5-spot to 7-spot inverted patterns. Injector wells have a selective string completion, with mandrels and packers that allow having control on the vertical distribution of the volume of water per mandrel group. In order to monitor water flood performance in the field, a reservoir surveillance methodology, based on dimensionless variables, has been implemented. The methodology was originally applied for a CO2 flood surveillance and was later extended to fit water flooding monitoring purposes. The paper presents the application of the dimensionless methodology, which allows the evaluation of water flood areas independently of their pattern configuration. This allows the comparison between patterns, sector or areas versus a theoretical ideal performance curve and quickly identify underperforming patterns in order to propose remedial actions. The application of this methodology has opened new opportunities in the field including the identification of well candidates for chemical stimulation jobs and conformance jobs, isolation jobs in producer wells as well as pump upsize opportunities. Additionally, it has improved the technical evaluation of workover jobs. Because of this, in the last four years La Cira Infantas has extended its portfolio activity, executing over 400 workover jobs. More importantly, it has allowed the transfer of more than 20MMBO into PDP reserves, and the production of 3,000BOPD of incremental oil production per year since 2014. This paper will provide an insight into the water flooding surveillance carried out in La Cira Infantas, which has proven to be very successful in Oxy's business units.