Huff Puff Gas Injection Pilot Project – A Case Study with Successful Results

摘要

Injecting gas, shut-in well and producing oil using a single well technique (huff & puff) was used as a pilot project to accelerate the oil recovery factor in compartmentalized reservoirs at Orocual Field, eastern area of Venezuela. The pilot project experimented with the objective of exploring non conventional and economic strategies to accelerate the local oil recovery. The medium oil reservoir (API 24-32 degree) is predominantly contained in a collapsed structure that has originated dozens of compartments which have inclination dip between 20-45 degree. The oil production and reservoir pressure declined sharply with recovery factors of less than 10% being achieved. The first IOR screening came up with different well strategies MLT wells, waterflooding process but none of these were economic at the time. An economic alternative is to use the current gas lift network to inject gas in the perforated oil leg and take advantages of gravitational segregation to displace the remaining oil. The strategy was executed in three main operational steps:injecting, shut-in and open to production. The pilot was executed in three vertical wells, each receiving more than three cycles. The results showed that the compartments energized rapidly and production increases signifcantly. This paper describes those lesson learnt acquired during the execution of the pilot covering screening process, reservoir simulation, pilot testing and field implementation design.