Several Indonesian gas fields such as the Tunu field exhibit a specific behavior which causes a rapid decrease of the gas production. At shut in conditions, cross-flows from watered out layers to gas producing layers, were clearly identified as the major cause for gas production impairment. The offloading of water from wells is performed at the preliminary stage of water production and often allows restarting the wells, but in a second stage it is ineffective. The nature of the damage in the gas-producing zones is not entirely understood but it seems to be a combination of at least two phenomena:water adsorption on the high amount of clays present in these highly water sensitive layers (15 to 40 wt %) andwater imbibition due to some capillary pressure experienced in the tightest layers (0.1 to 10 mD). Clay swelling or migration seems also to contribute for this damage but to a lesser extent. Unwanted water along with gas and condensate production from several layers were quantified from multi-rate PLT, to define a strategy for well candidate selection and water shut off interventions. An inorganic gel was then selected to be selectively squeezed into the water-producing layers. The optimization of this fluid and of the preflush fluid required a complete qualification program which aimed at three main objectives:maintain injectivity during the squeeze to allow an entire placement of the fluid,provide, once set an extrusion pressure sufficient to withstand a significant drawdown andgives a treatment's lifetime of one year minimum. Three wells were treated in 2004, following the qualification of the fluids, the selection of candidate wells and the implementation of a complete treatment setup on a barge. This article describes the successes and the failures of some of them, pointing out the need for finely filtered fluids, low viscosity fluids and robust selective placement tools. Introduction The Tunu field operated by Total Indonesia is a north-south elongated structure of 80 km long in the shallow swampy outer edge of the Mahakam delta region of East Kalimantan. It is a giant field of approximately 70x20x25 km size.

Total E&P Indonesie (TEPI) is the main gas producer in Indonesia which produces around 1900 MMscf/d of gas. One of the challenges is to maintain its production plateau under liquid loading issue. Almost half of TEPI gas production comes from liquid-loaded wells, representing 85% of total producing wells in the affiliate. Up until recently, dewatering activity in TEPI is only performed by means of regular offloads; involving substantial means. These operations present specific risks not only for safety and assets but also for environment by flaring of gas through testing barge. A cross functional team has been established to find out innovative solution based on the "Foam Assisted Lift" (FAL) principle and enabling to keep existing DHSV in the well completion. The FAL principle consists in offloading the wells by creating foam down-hole through continuous injection of surfactant to help liquid lifting and gas breakthrough. This paper describes Capillary String Injection System that can be fitted into existing wells, using existing DHSV control line for surfactant injection while keeping its primary safety function as a fail-safe device. The installation equipment includes a modified wireline-retrievable surface-controlled sub-surface safety valve (WR-SCSSV) with capillary tubing attached below it. Injection operates via existing control line of the safety valve to inject chemicals, does not require any further wellhead modification. In addition, this system fits perfectly with the context of mature field; simple, cost-effective, safe and easy to handle.

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