| dc.description.abstract | In this thesis the productivity of well 25/8-D-1 AH T3 in the Jette field has been evaluated by estimating the productivity index. The productivity index has been estimated in two ways; with the use of a pseudo-steady state model and multi-rate tests. It was observed that the well suffers from a poor Productivity Index (PI), with a low and unstable production due to slugging. A sensitivity analysis was performed on several input parameters in order to investigate the reasons for the poor PI. The sensitivity analysis gave indications to what kind of well intervention measures which may be reasonable to implement in order to increase the productivity.
Six cases of well intervention measures were implemented and simulated with
Schlumberger's simulation propriety ECLIPSE 100. The cases consist of infill drilling and acid squeeze. All six cases showed an increase in Recovery Factor (RF); 1-30% increase from the basecase. The new well paths were designed with the Petrel software to obtain an optimized connection factor, giving a smoother wellbore location in the grid blocks. Up to four completion options have been suggested for the cases, where the most optimal options have been considered to be a barefoot solution or a an openhole completion with standalone metal mesh screens, inflow control devices and swell packers (as well 25/8-D-1 AH T3). The Net Present Value (NPV) was calculated for all cases and completion options with the basis of the costs and revenue, and have been used to evaluate the sustainability of the well intervention measures.
The infill drilling measures consist of laterals towards north, east and west of Well D. It is observed, from the simulations, that the laterals towards east give highest increased oil RF compared to the basecase; 29.2%. Acid squeeze gives an increased oil RF of 9.8%. The costs of the drilling and completion operations were calculated using all inclusive day rates. Assessed risks and unforeseen time delays due to conditions like hole instability and cleaning, well control, stuck pipe, etc. were included in the probability distribution. Almost all cases were found to obtain a positive NPV, being profitable. Case 2 and Case 3, with laterals towards east, are found to be the most profitable cases. | |
