Tunu and Tambora gas fields are located in the Mahakam river delta in the province of East Kalimantan, Indonesia. The fields consist of wet gas bearing sand bodies over a height of 13000 ft. Most of the wells are multizone gas producers completed with cemented tubing without primary sand control, and are produced with a bottom-up perforation strategy. The main objective is gas production from the deeper Main Zone layers. The shallower reservoirs prone to sand production were not targeted until recent years. With progressing depletion of deep reservoirs in the Main Zone and bottom up perforation strategy the operator started perforating upper zones. This resulted in an increasing number of interventions or shutting wells in due to sand production. Due to this fact the operator started considering remedial sand consolidation about 5 years ago. The first successful trials using internally catalysed epoxy resin fluid were prepared in late 2008 and results presented at the 2010 SPE International Symposium and Exhibition on Formation Damage Control (Chaloupka et al. 2010). Initially, these consolidation treatments aimed to find a remedial solution for existing wells choked back or shut in due to sand production. These successful trials, however, quickly turned the project into using consolidation essentially as a primary sand control method. First treatments targeted weakly consolidated sands in both Tunu and Tambora fields (5,000 to 8,000 ftTVD) using high temperature internally catalysed epoxy consolidation fluid. The treatments showed encouraging results and confirmed this as a viable option for sand control. In 2010 with growing confidence in the method the operator considered performing sand consolidation in very shallow fully unconsolidated Tunu Shallow zones (2,300 to 5,000 ftTVD) as an alternative to standard single trip multi-zone gravel packs which are conventionally pumped in Tunu Shallow. Five treatments have been performed using a low temperature version of the consolidation fluid with encouraging results. The preliminary performance envelope validated from the treatment is 3 MMscfd of gas per meter perforated or a drawdown of 300 psi. The paper aims to describe the experience from the initial trials to field application including placement and fluid QAQC procedures as well as treatment results. The failures and difficulties that have been encountered are looked at in more details.

Extensive laboratory testing was conducted to qualify new internally catalyzed consolidation system. The tests were conducted both using sand packs and core samples and were to measure post treatment compressive strengths, regained permeabilities, rheological properties and working time of the fluid. The results of the above tests are presented as well as fluid field trials performed in shallow gas reservoirs in Tunu giant gas field located in the Mahakam river delta in the province of East Kalimantan, Indonesia. The development of the fluid and its field application were driven by the search for an effective alternative to conventional primary sand control methods that would allow developing marginal reserves where the conventional methods might not be economical. Unconsolidated sand packs treated with the new consolidation fluid led to high compressive strengths and regained permeabilities. The tests performed on Tunu core samples showed similar improvements in unconfined compressive strength (UCS) and regained permeability. This was despite the fact that these formations can have very undesirable properties for sand consolidation as per common industry belief with high shale content up to 25 % and d50 of formation being as low as 30 μm. Two treatments were successfully performed on shallow unconsolidated layers using coil tubing. The reservoirs produced at gas rates up to 2.8 MMscfd and 4.0 MMscfd sand free. The new consolidation fluid was successfully qualified through a series of core flooding tests and field tests. As opposed to the comparable products currently available on the market, the fluid has low flammability rating significantly improving the safety aspects of the treatment. The treatment using this new consolidation system showed that it can provide a viable primary sand control option for developing marginal gas reserves.