Development and Application of Wellbore Flow Assurance Monitoring System for Combustible Ice Production in Deepwater

Abstract

The commercial development of combustible ice, as the most promising strategy energy, requires not only efficient gas production technology but also a safe flow assurance system. For the depressurization development of combustible ice in the sea area, the issues of wellbore fluid carrying sand, hydrate re-formation in the wellbore, and instability of wellbore flow, are the key problems leading to flow obstacles in the well bore and affecting the normal production. Therefore, some measures must be taken to effectively monitor and analyze the flow situation in the wellbore during the development of combustible ice in the sea. In this paper, a Wellbore Flow Assurance Monitoring System (WFAMS) is developed to display the fluid flow conditions in the wellbore in real-time during the gas hydrate production, including temperature, pressure, flow rate, the carrying sand amount, etc. In addition, the system can monitor the plug risk online, which involves sand plug and hydrate block resulting from gas hydrate reformation, and the flow stability, and it can give some valuable information such as the production adjustment data and the injection amount of hydrate thermodynamic inhibitors. This system has been applied in the second production test by depressurization in the South China Sea in 2020 and succeeded in predicting the flow conditions in the wellbore, which helps the field engineers to timely monitor the flow risk in the wellbore and adjust the production plan, thus which can provide a favorable guarantee to ensure the smooth progress of production test.

Keywords: Combustible ice, Flow assurance, Depressurization development, Monitor system