TY - THES

T1 - Optimization of well start-up

AU - Schietz, Michael

N1 - embargoed until null

PY - 2009

Y1 - 2009

N2 - This Master of Science Thesis deals with oil-well start-up and the necessity of optimizing such operations. Coupling a reservoir model with a wellbore flow model is suggested as an ideal way to capture and tame complex transient flow phenomena encountered in this production phase. Having described the approach and working principle of the chosen explicit coupling strategy, simulation and optimization results are presented and a qualitative comparison with real well start-up data is given. Beginning with outlining current common practice in well start-up operations and demonstrating the necessity for improvement, the paper continues with an extensive description of thereby encountered flow events. The used commercial simulator software for modelling reservoir- (SENSOR 6k) and pipe flow (OLGA 6 GUI) is introduced and the respective generic model configurations are explained. The main part of this paper deals with the chosen strategy for coupling these models and the subsequent implementation using the process-integration and -optimization application Pipe-It. Furthermore, the importance of appropriate time-step selection is emphasized, followed by a presentation of optimized simulation results obtained from the two core strategies: fixed and variable coupled-model time-steps. Qualitative model verification, further methods for coupling, concluding remarks and recommended continuative work constitute this thesis final section. This project has been carried out in close cooperation with the Norwegian University of Science and Technology (NTNU), Petroleum Engineering Reservoir Analysts (PERA a/s) and the StatoilHydro Research Centre Trondheim as well as the respective supervisors Prof. Curtis H. Whitson and John Petter Jensen. The employed software was kindly provided by Petrostreamz AS, SPT Group Norway AS and Coats Engineering Inc. Valuable input came from several industry experts, while further information was taken from technical books and journals, SPE papers and the internet. All used sources were stated using the ISO 690 convention for citation, in order to give credit to the authors and make sure that continuative research can start from this papers final state of knowledge.

AB - This Master of Science Thesis deals with oil-well start-up and the necessity of optimizing such operations. Coupling a reservoir model with a wellbore flow model is suggested as an ideal way to capture and tame complex transient flow phenomena encountered in this production phase. Having described the approach and working principle of the chosen explicit coupling strategy, simulation and optimization results are presented and a qualitative comparison with real well start-up data is given. Beginning with outlining current common practice in well start-up operations and demonstrating the necessity for improvement, the paper continues with an extensive description of thereby encountered flow events. The used commercial simulator software for modelling reservoir- (SENSOR 6k) and pipe flow (OLGA 6 GUI) is introduced and the respective generic model configurations are explained. The main part of this paper deals with the chosen strategy for coupling these models and the subsequent implementation using the process-integration and -optimization application Pipe-It. Furthermore, the importance of appropriate time-step selection is emphasized, followed by a presentation of optimized simulation results obtained from the two core strategies: fixed and variable coupled-model time-steps. Qualitative model verification, further methods for coupling, concluding remarks and recommended continuative work constitute this thesis final section. This project has been carried out in close cooperation with the Norwegian University of Science and Technology (NTNU), Petroleum Engineering Reservoir Analysts (PERA a/s) and the StatoilHydro Research Centre Trondheim as well as the respective supervisors Prof. Curtis H. Whitson and John Petter Jensen. The employed software was kindly provided by Petrostreamz AS, SPT Group Norway AS and Coats Engineering Inc. Valuable input came from several industry experts, while further information was taken from technical books and journals, SPE papers and the internet. All used sources were stated using the ISO 690 convention for citation, in order to give credit to the authors and make sure that continuative research can start from this papers final state of knowledge.

KW - start-up explicit coupling coupling strategy transient flow time-step reservoir model wellbore flow model process integration optimization Nelder-Mead simplex solver OLGA Olga SENSOR Sensor Petrostreamz Pipe-It generic mode

KW - start-up explicit coupling coupling strategy transient flow time-step reservoir model wellbore flow model process integration optimization Nelder-Mead simplex solver OLGA Olga SENSOR Sensor Petrostreamz Pipe-It generic mode

M3 - Master's Thesis

ER -