Liquid Screen: A Novel Method To Produce an In-Situ Gravel Pack

Abstract

Summary Gravel packs are conventionally used as a permeable solid layer in the annulus between a production screen and the walls of the wellbore in weakly consolidated subterranean formations. Gravel packing is a well-known technique for sand control, whereby unconsolidated fines produced from the soft formation are filtered away from the production fluids. However, gravel packs can be problematic. The bridging of sand particles within the gravel pack can create voids that can result in mechanical failures or significantly reduce the effectiveness of gravel packs to restrain fines from flowing along with the hydrocarbons produced. As an alternative, we present a pioneering method to prepare void-free and mechanically sound permeable barriers in subterranean formations as an alternative to gravel packing. The method of preparation involves the curing of Pickering water-in-oil medium-internal-phase emulsions (MIPEs) or high-internal-phase emulsions (HIPEs) containing monomers in the annular space between a rock formation and pipe. The emulsions were prepared simply by adding low amounts of nonionic surfactant and dispersant to premade Pickering emulsions that were stabilized by oleic-acid (OA) -modified silica particles. The resulting macroporous solid materials, known as “poly(merised)Pickering-M/HIPEs,” have a gas permeability of up to 2.6 darcys and are highly interconnected and permeable to hydrocarbons. This paper shows that it is possible to tailor the gas permeability and mechanical performance of the permeable barrier by altering the emulsion internal-phase volume, the volume of surfactant added to the premade Pickering emulsion, and the composition and constituents of the continuous monomer phase; styrene, divinylbenzene (DVB), and poly(ethylene glycol) dimethacrylate were used in the monomer phase.