Study of the rheology and flow risk of hydrate slurries containing combined anti-agglomerants: Effects of wax, water cut and continuous phase composition

As oil and gas extraction increasingly ventures into deep-sea environments, the issues surrounding the flow safety of hydrate and wax deposits have become more critical. There is an urgent need to develop environmentally friendly and adaptable hydrate anti-agglomerants, and to expand the database and knowledge base for risk management strategies to ensure optimal production safety. This study formulated combined anti-agglomerants with varying HLB values using Span 80 and Tween 80 in different ratios. Rheological experiments were conducted to investigate their synergistic anti-agglomeration performance in water-in-oil emulsions and their adaptability in environments with wax, varying water contents, and different continuous phase compositions. The results indicate that, in comparison to a single anti-agglomerant, the combined anti-agglomerants not only increases the critical time for hydrate formation but also reduces peak viscosity and stable viscosity by 23–90 % and 25–85 %, respectively. Additionally, an index for assessing the flow risk of hydrate slurries under specific conditions was proposed, which demonstrates that the combined anti-agglomerant with an HLB value of 8.6 exhibits exceptional performance across various conditions. This finding is significant for refining risk management strategies for hydrates in deep-sea oil and gas transportation processes.