Effect of Fast-Swelling Porous Hydrogel on the Reduction of Filter Loss for Water Based–Drilling FluidsAuthor(s): Fawzia I. El-Dib, M. M. Dardir, Gh. Eshaq and M. M. Fayad
Filtration is one of the desired properties of a drilling mud that it should minimize fluid loss from the well bore into the surrounding. Fluid loss is the measurement of filtration passing from the drilling fluid into a porous permeable formation. Low fluid loss is a characteristic of good drilling fluid and is the key to borehole integrity. In this study two samples of fast swelling highly porous superabsorbent hydrogel (HPSHs) were synthesized via rapid solution polymerization of partially neutralized acrylic acid in presence of N, N'-methylenebisacrylamide (MBA) as cross-linking agent under atmospheric conditions, ammonium persulfate (APS) as initiator and (acetone and sodium bicarbonate) were used as a porosity generators to create highly porous structures with highly rate swelling. Another sample of superabsorbent hydrogel (SH) was synthesized via rapid solution polymerization, with the same ingredients but without using (acetone and NaHCO3). And the results showed that (HPSHs) have more swelling capacity than (SH). The new prepared (SPHPs) and (SH) were investigated as viscosifiers and filter loss additives for water–based drilling fluids formulated from local Egyptian clay (Na–bentonite) to improve the rheological and filtration properties .The study of rheological and filtration properties of water based mud treated with the new (SPHPs) and (SH) indicated that (SPHPs) have the best results for improving of the rheological properties and reducing filter loss and mud cake of water-based mud than the corresponding reference water-based mud treated with the conventional filter loss (carboxymethylcellulose). The results of mineralogical studies and scanning electro microscopy (SEM) for the water based mud treated with (SH) and (SPHPs) indicated that both of the new prepared (SH) and (SPHPs) were intercalated and attached strongly to the local Na-bentonite clay.