Aguada Pichana Gas Field Development: Key Parameters for a Successful Well Design

The development of the Aguada Pichana gas field in the west of Argentina, required a drastic reduction in drilling costs as well as effective hydraulic fracture stimulation to increase well productivity. Local drilling and stimulation practices had to be rethought and innovative solutions found for the project to be economically successful. This paper focuses on the following aspects: Drilling and Completion: Cost economies achieved by using a reduced diameter (6 1/8) well design, use of a compact wellhead, bit optimisation, and reduction of drilling time by maximising rigless operations. Stimulation : The impact of changing the conventional fracture fluid used by other operators in the region in order to allow higher proppant concentrations to be pumped and allow fracturing through the 2 7/8completion. Fracture design in order to avoid fracture growth into a water zone is also discussed. Horizontal Wells: 2 horizontal wells and 23 vertical wells were drilled. 18 of the vertical wells were hydraulically fractured. The relative merits of a horizontal versus a fractured vertical well design are highlighted. The first phase of the field development took just over 1 year to complete, using 2 drilling rigs and 1 workover rig. Gas production from the 34 wells (25 new wells and 9 workovers) began in January 1996 and currently stands at 5 Mm3/day. The positive results of the combined operations meant that a stabilised gas potential much higher (+70%) than anticipated was achieved along with cost savings for the project.