Microencapsulated Chemical Program for Long-Term Downhole Bacterial Protection

Abstract An effective downhole chemical delivery system for bacteria control uses microencapsulated THPS/THPC in synergy with other powerful additives to manage bacterial growth and prevent corrosion. The objective is to treat the well from the bottom below the pump intake for extended periods, exceeding one year. A standard procedure involving microencapsulation chemistry for downhole applications was implemented in the technical design for bacteria control. The procedure began by collecting samples from the study well, which had significant issues with bacteria and hydrogen sulfide. As part of the protocol for this micro-encapsulated technology, water and solid analyses were conducted to develop a successful plan to mitigate the problem. Additionally, the bacteria population was evaluated before implementing microencapsulated technology by using ATP analysis to track and compare the chemical treatment efficiency in controlling bacterial population monthly. Based on these results, solid sticks of THPS and THPC were tested with the production fluid to evaluate their performance before installing the treatment in the well. The bacterial population was controlled by achieving up to 96% efficiency during eight months of tests when compared to the initial state before implementing the microencapsulated technology. The traceability of chemical dispersion downhole was determined by analyzing chemical concentration using residual samples, complemented by monthly ATP analysis. The success of the microencapsulated application was confirmed by measuring residual chemical concentrations, which indicated continuous dispersion of the microencapsulated chemical. Additionally, iron and manganese levels remained stable despite the presence of H2S, indicating effective corrosion control. Preliminary studies on the solid and water quality of the well were crucial in formulating the optimal chemical combination and recommendations. In addition to focusing on bacterial inhibition, we incorporated corrosion and scale inhibitors, as these tendencies were identified through our current software simulation. The novelty of the current microencapsulation program lies in its unique ability to deliver long-term chemical treatments downhole with consistent chemical dispersion. This technology offers a distinctive alternative that enhances runtimes and provides comprehensive inhibition from bottom to top, reaching areas where other technologies cannot. Wells treated with this technology have demonstrated inhibition for up to 900 days in some cases.