The phenomenon of fines migrating through porous and permeable paths is well-known, as are the issues related to fines migration. During the life of a producing well, fines can migrate and reduce formation permeability by clogging pore throats of the mineral grains and reduce conductivity of proppant packs placed by hydraulic fracturing treatments, Frac Packs, or by gravel pack operations. Such fines migration can eventually lead to reductions in well production. The primary contributing factors that release fines are high fluid velocity, changes in salinity, wettability, pH, and rock failure. Use of a surface modifying agent (SMA), which can immobilize fines in place, helps minimize or mitigate fines migration. However, solvent-based SMAs are difficult to apply as a remedial treatment, and this limits their applicability.
This paper discusses the use of an aqueous-based surface modifying agent (ASMA) that can be used to help mitigate fines migration. The ASMA is a conductivity enhancer that immobilizes fines by locking them in place as a result of its tacky surface. Because it is hydrophobic in nature, it resists water flow without hampering hydrocarbon flow.
The ASMA can be pumped into formations having permeabilities greater than 100 md as a remedial treatment. It also can be coated onto proppants immediately before pumping them downhole.
To demonstrate the efficiency of the ASMA, a number of laboratory experiments were conducted on sand packs consisting of a sand-fines mixture and proppant, which closely simulated actual downhole conditions. Control tests (without the ASMA treatment), pre-coating of proppant pack tests, and remedial treatment tests were performed at different flow rates to study the effect of fines migration along with the efficiency of the ASMA as a technique to mitigate the issue.