Publications

Tunu is a multilayer gas field operated by Total EP Indonesie in the Kutai basin, which produced around 8Tcf of gas since 1993. It consists of thousands of gas-bearing sandstone reservoirs, spread over up to 2000m of vertical gross thickness, developed using tubingless completions (more than 700 wells to date). Perforations are performed by light electric unit swamp barges, following a progressive bottom-up strategy. Perforations techniques applied in the field all involve perforating in static Under Balance pressure conditions. In several cases, gas reservoirs with moderate production rates compared to their remaining associated reserves have been identified. To stimulate them, re-perforations of these reservoirs have been performed to increase their productivity and improve the recovery. Since 2007, more than 200 reservoirs have been re-perforated in Tunu, with spectacular results in many cases. As re-perforations involve costs similar to those of initial perforations, it is essential to focus this activity on reservoirs where the benefit will be the highest, that is to say where some damage to the initial perforations is observed or suspected, usually through wellbore skin effect. This paper will discuss the way candidates to reperforation are screened and selected, the conditions of success of re-perforations, and the results in terms of production associated to these light well interventions.