Resolving a Flow Assurance Issue at Offshore Field: A Successful Novel Technology Deployment

Abstract Solid scale like deposition is one of the most common flow assurance challenges, both subsurface and surface. Solid deposition above a certain limit may limit outflow and productivity. An offshore field in Malaysia has suffered mixed scales (wax and inorganic scale), which has decreased oil production. As observed from the well site, the recovered sample was retrieved from the tubing in the wellbore. This paper presents a successful deployment of in-house novel technology to resolve a potential flow assurance issue due to mixed scales in the offshore field. The mixed scales build-up over time and eventually reduces the effective flow path leading to a flow restriction or eventually a blockage of the line. Mixed scales deposits in tubing reduce the inner diameter and flow rate. Eventually, the wax forms a blockage, prohibiting oil production. Comprehensive analysis and evaluation both in the laboratory and well were carried out, integrated with thermodynamic modelling prior to novel technology deployment in the field. The loss of ignition test revealed that more than 99% of the deposit is an organic material and the rest is inorganic. PVT fluid data was characterized using the EOS model, and fine-tuned fluid properties achieved an acceptable match with PVT experimental data as a validation process. The comparison of wax content between laboratory measurements and model prediction is acceptably accurate. Laboratory measurements and model predictions match wax content. The in-house chemical treatment was developed and successfully dissolved mixed scales overnight, according to dissolution tests. The compatibility test with existing production chemicals such as scale inhibitor (SI), corrosion inhibitor (CI), and wax inhibitor (WI) was also performed, and the in-house chemical had no incompatibility issues. This study demonstrates how vital and necessary proper with thermodynamic modelling analysis is prior to well put onstream to anticipate any flow assurance issues that may cause decreased and prohibited oil production. Simultaneously, this paper successfully identified the suitable chemical treatment to control mixed scales in this field.