Drilling and operating a horizontal or vertical infill well – An analysis showing the differences in capital expenditure and operating expenses

Marieluise Pöschko

Research output: ThesisMaster's Thesis


The objective of this thesis was to clearly analyze the specific phases during the life cycle for horizontal and common vertical wellbores including an economic field study to explain the value given by them. Additionally it was possible to achieve a detailed comparison and data collection concerning the various phases during the life cycle of each well type. The conducted literature review in the beginning of the thesis was performed based on previously used operation technologies for maintaining a general overview of any possible field option. Further, the focus was directed to the various steps during the life cycle of each well type starting with the planning phase, drilling technologies, operation phase and well abandonment. Several pre-defined well constraints limited the amount of wellbores that need to be analyzed to seventeen type wells. These wells were further divided into four different types of wellbores, which were than taken into consideration during the whole life cycle analysis. In the final chapter a lifecycle cost analysis of these specific well types was performed that directly opposes the operational expenditures and the capital expenses. It was possible to clearly highlight the occurring differences during these stages within a hydrocarbon production time of 10 years. Several influencing factors concerning the decision whether to drill a horizontal or vertical wellbore were summarized and pointed out. During the comparison of the total expenditures it was found out that only two of the four pre-chosen well types were comparable in costs. A difference of 24% in total life cycle costs between horizontal and vertical wellbores with a length of minimum 2000m and sucker rod pump installation was visible. Even though , a horizontal wellbore equipped with electric submersible pump with a length of minimum 2000m compared to a vertical wellbore with the same length and sucker rod pump installation showed a difference of 53% in total costs, it was pointed out that this comparison was not countable due to the different pump installations and the short period of production history. The outcome of this thesis was created to provide valuable information concerning the decision whether to drill a horizontal or vertical infill well and to clarify the benefits of each wellbore.
Translated title of the contributionBohrung und Produktion einer horizontalen oder vertikalen Infill-Sonde - Eine Analyse, die die Unterschiede in den Investitions- und Betriebskosten aufzeigt
Original languageEnglish
Awarding Institution
  • Montanuniversität
  • Fazeli Tehrani, Fatemeh, Co-Supervisor (internal)
  • Hofstätter, Herbert, Supervisor (internal)
  • Nirtl, Michael, Supervisor (external)
Award date23 Oct 2020
Publication statusPublished - 2020

Bibliographical note

embargoed until 17-08-2025


  • vertical wellbore
  • horizontal wellbore
  • life cycle analysis

Cite this