Publications

Since the field’s start up in 1990, Tunu field has delivered > 9 Tcf of gas production mostly contributed from Tunu Main Zone (TMZ) reservoirs. Tunu Shallow Zone (TSZ) reservoirs were considered as drilling hazard. With time, TMZ was more and more depleted, hence the development of TSZ became the new focus. As the TSZ becomes mature, it is challenging to find target for new wells with reserves greater than 1.5 Bcf. In addition, with current low gas price, completing these marginal wells using currently proven Gravel Pack (GP) well design makes these wells uneconomical. Alternative for sand management to reduce the well cost is necessary to continue developing TSZ. In 2009, TEPI introduced a chemical-based sand control technique called Sand Consolidation through a pilot. The cost of new sand consolidated well is much less than GP however the reliability needs to be proven. The pilot was a success and soon followed by industrialization phase. Considering the economical aspect, the minimum stake required for the sand consolidation is 0.15 Bcf. Further economical improvements are also done on operation, technical, and contract negotiation. At the beginning, the operating envelope of sand consolidated well in Tunu was limited by drawdown of 20 bar and maximum gas production rate (Qg) of 2 MMSCFD, merely based on empirical approach. After further evaluation, new parameter is used to control the sand consolidation integrity i.e. in-situ gas velocity across the perforation hole. Maximum Qg is no longer a limiting parameter. By implementing in-situ gas velocity of 4 m/s and maximum drawdown of 30 bar, recent Tunu sand consolidated wells have been produced with higher Qg (> 2.5 MMSCFD) without significant issues on productivity and sand. Tunu high rate sand consolidated well remains as efficient and cost-effective sand control technique to unlock TSZ reservoir with limited reserve. Keywords: Tunu, sand control, sand consolidation, shallow reservoir, cost-effective