Experimental Analysis of Scale Inhibitors Retention in Carbonate Formations for Application in Squeeze Treatments

Abstract

In this work, static adsorption/precipitation (Γ/Π) experiments were conducted for two widely used scale inhibitors (DETPMP and VS-Co) using two different size fractions of Moroccan calcite (315–500 and 125–250 μm) to study the effect of particle size on the “apparent adsorption” of these SIs onto carbonate. The reason for performing these experiments at two particle size ranges was to determine whether the relative surface area to volume ratios (as presented as particle size) would affect whether the precipitating SI–Ca complex forms as a “skin” on the mineral surface and, if so, to determine whether this “skin” could affect the further interaction between the SI and the carbonate mineral by a “surface poisoning” effect. The results of both environmental scanning electron microscopy/energy dispersive X-ray analysis (ESEM/EDX) and direct particle size analysis (PSA) clearly showed that no (or very little), such surface deposition or coating around calcite grains occurred for either of these SIs. Essentially, the results for both particle sizes were qualitatively the same for each of the SIs. The DETPMP retention showed coupled Γ/Π behavior, which was predominantly precipitation at [DETPMP] > 100 ppm and was quantitatively almost the same for both calcite particle sizes. Likewise, the results for VS-Co were quantitatively almost identical for both particle sizes and the retention was predominantly via adsorption up to [VS-Co] ≈ 3000 ppm, with some small degree of precipitation at higher concentration observed. The rather different behavior of DETPMP and VS-Co may be ascribed to different functional groups having different pK a values and strengths of SI–Ca binding. Both sets of static adsorption/precipitation experimental results for DETPMP and VS-Co on each calcite particle size fraction were also predicted using a previously published model.

Mitigation of Mineral Deposition in Carbonate and Sandstone Rocks Using Green Scale Inhibitors

“…It could be justified according to the dolomite tendency to react with the precipitated calcite in the brine during the core flooding experiments, while sandstone is not commonly participated in such reactions. 54 As for the dolomite rock sample, folic acid performed much better compared to inulin since the calcium concentration was much higher in the solutions with folic acid for both different injection flow rates. It could also be inferred from Table 6, which presents the inhibition efficiency (IE %) of SIs, that greater values of IE %, for both injection flow rates, were obtained for folic acid (49.2 and 39.5%) than those for inulin (28.3 and 29.3%).…”

Evaluation of Polyelectrolyte Complex Nanoparticles for Prolonged Scale Inhibitor Release in Porous Media

“…Previous studies in the petroleum and pharmaceutical literature have modeled component release from a nanoparticle polymer matrix as a diffusional or dissolution process. ,,− Kan et al modeled the behavior of SI squeeze and squeeze lifetime in a reservoir using a combination of a peak function and solid-phase stoichiometry-based solubility products and diffusion coefficients. Arifin et al presented a detailed review of existing mathematical models and their implications for drug delivery systems.…”