Αξιολόγηση πιθανών προβλημάτων διασφάλισης ροής σε ένα πηγάδι παραγωγής : Assessment of possible flow assurance issues in a production well

• Main Author: Βαρβαντακης Μιχαηλ
• Format: Text
• Language: English
• Published: Technical University of Crete 2015
• Subjects: Arctic; permafrost
• Online Access: https://dx.doi.org/10.26233/heallink.tuc.40621; https://dias.library.tuc.gr/view/40621

Hydrocarbon exploration becomes complicated due to recent developments in offshore, deepsea and permafrost zones. Field developments in areas never explored before introduce new issues that have to be tackled from the production engineers to achieve economic production rates. Flow assurance in pipelines and specifically hydrate formation, becomes an issue of major importance in the system design of hydrocarbon fields. The objective of this thesis is the assessment of the hydrate forming conditions in a hydrocarbons production system when the system design parameters are varied. The first part is introductory and deals with the flow assurance issues occurring in petroleum industry operations. Subsequently, it focuses on one of the most important flow assurance issues, the hydrate formation. A review on hydrate thermodynamics and probable areas of formation in gas and oil-dominated systems is given, followed by a brief analysis on how hydrate plugs are formed. Finally a short discussion about the hydrate potential as a hydrocarbon resource is given followed by a presentation of all possible remedial applications on the hydrate problem, be it prevention or treatment. The second part deals with hydrate formation on two hydrocarbon systems (Light Oil and Gas condensate) at two developed fields which represent an onshore arctic and a deep offshore region. A sensitivity analysis was done to study how the system parameters affect the hydrate forming conditions. For this task, PROSPER by PetEx, the industry standard production simulation software was utilized to simulate all possible scenaria. The sensitivity analysis is split into two parts. The first discusses the effect of system parameters that affect the well deliverability (VLP curve) and the second deals with the effect of two thermodynamic inhibitors in various concentrations. Concluding, the effect of all system parameters on the hydrate formation is given. The parameters that stand out are: the water percentage of the flow stream and the pipeline insulation. Both are equally important parameters that can deteriorate or eliminate the hydrate formation problem regardless the environmental conditions prevailing at the field development. Classical design against hydrate formation is targeting to the avoidance of the hydrate stability region, however new methods are under development, which shift their targeting in producing the hydrate particles and further research must stand up to that task.