TY - THES

T1 - Relief Well Profile Analysis and Evaluation of a Passive Seismic Method for Relief Well Placement in the Shallow Wisting Discovery

AU - Kurz, Manuela

N1 - embargoed until 04-11-2023

PY - 2018

Y1 - 2018

N2 - A blowout is one of the most catastrophic events that can happen in the oil and gas industry, requiring operators to have relief well strategies in place for intersecting the out-of-control well in the worst-case scenario. The Wisting discovery imposes a unique challenge on the relief well trajectory: It is exceptionally shallow, thereby providing too little depth for the industry standard S-shaped design. Therefore, the operator has devised three J-shaped designs for potential relief wells, all of which are difficult to drill because they require either extremely high inclinations or a very high build rate. Further, the intersection process of the blowing well is complicated by the J-shaped design, leading to a longer estimated time for successful intersection and thus to an increased amount of damage in the case of a blowout. To provide a criterion for identifying the best compromise between high build rate and high inclination, the thesis introduces a relationship between the two parameters that allows to derive a most effective build rate and corresponding inclination. The goal is to help the operator decide if one parameter should be reduced on the expense of the other, resulting in an optimized trajectory within the technical limitations of the drilling tools. Further, it provides the operator with comparable, quantitative results to justify the need for the development of higher capability directional drilling tools. To enhance the intersection process with a J-shaped relief well, it is necessary to improve the wellbore positioning accuracy. For this purpose, a seismic event positioning system that has been field tested in Wisting is evaluated for its suitability in reducing the uncertainty in the wellbore position derived from survey measurements. The objective of this evaluation is to assess if further investigation of this seismic method is likely to bring an improvement to the positioning accuracy of directional wells.

AB - A blowout is one of the most catastrophic events that can happen in the oil and gas industry, requiring operators to have relief well strategies in place for intersecting the out-of-control well in the worst-case scenario. The Wisting discovery imposes a unique challenge on the relief well trajectory: It is exceptionally shallow, thereby providing too little depth for the industry standard S-shaped design. Therefore, the operator has devised three J-shaped designs for potential relief wells, all of which are difficult to drill because they require either extremely high inclinations or a very high build rate. Further, the intersection process of the blowing well is complicated by the J-shaped design, leading to a longer estimated time for successful intersection and thus to an increased amount of damage in the case of a blowout. To provide a criterion for identifying the best compromise between high build rate and high inclination, the thesis introduces a relationship between the two parameters that allows to derive a most effective build rate and corresponding inclination. The goal is to help the operator decide if one parameter should be reduced on the expense of the other, resulting in an optimized trajectory within the technical limitations of the drilling tools. Further, it provides the operator with comparable, quantitative results to justify the need for the development of higher capability directional drilling tools. To enhance the intersection process with a J-shaped relief well, it is necessary to improve the wellbore positioning accuracy. For this purpose, a seismic event positioning system that has been field tested in Wisting is evaluated for its suitability in reducing the uncertainty in the wellbore position derived from survey measurements. The objective of this evaluation is to assess if further investigation of this seismic method is likely to bring an improvement to the positioning accuracy of directional wells.

KW - relief well

KW - trajectory

KW - trajectory design

KW - J-shape

KW - S-shape

KW - Wisting

KW - wellbore positioning

KW - seismic event positioning

KW - shallow

KW - Erleichterungsbohrung

KW - Bohrpfad

KW - Bohrpfaddesign

KW - Wisting

KW - Bohrlochposition

KW - Bohrlochvermessung

KW - S-förmig

KW - J-förmig

U2 - 10.34901/mul.pub.2023.279

DO - 10.34901/mul.pub.2023.279

M3 - Master's Thesis

ER -