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.