Extended Release Phosphonate Scale Inhibitor for Enhanced Squeeze Application

Abstract Diethylenetriamine penta(methylenephosphonicacid) (DTPMP) is a commonly used phosphonate scale inhibitor for CaCO3 and BaSO4. Even though DTPMP can be squeezed into the reservoir, the duration of the flow back could be improved. Therefore, frequent injection is needed to maintain the minimum inhibitor concentration, which costs a lot of money, time and chemicals. There have been some studies carried out to extend the release life of DTPMP, but none was able to get into a level that can be scalable and proven in the field. Taking into consideration those facts, an extended release carrier platform for DTPMP (ER-DTPMP) was designed and synthesized to extend the squeeze life time of DTPMP while maintaining its excellent inhibition properties. ER-DTPMP was synthesized by attaching DTPMP into a proprietary carrier platform via various bridging components. Temporal product stability is shown well past five months and ongoing. The product has undergone extensive compatibility testing which includes product stability in high temperatures, compatibility with brine and KCl fluids, effect of shear, and high temperature and pressure. Possible formation damage was studied in regain perm experiments by measuring differential pressure across the core. Around 300% (3x) extension of lifetime of incumbent DTPMP was obtained for the ER-DTPMP, when performing core flood experiments using a sandstone core. Field trials are ongoing at the time of this publication and will be the subject of a consequent paper.