This master thesis addresses methods and best practices for defining performance measures and performance measurement systems in a Digital Oilfield environment. The first part is dedicated to the theoretical elaboration of performance measurement concepts and clarifying what the Digital Oilfield is. In the second part, the author explains the practical application of the methods and concepts described in the theoretical part. The author conducted this thesis project in collaboration with an Austrian company, which specializes in oilfield digitalization and smart brownfield solutions. Besides analyzing literature on the topic, the project ought to yield a set of KPIs for monitoring oilfield performance. The KPIs shall serve as a decision-making assistance that provides operators and managers with valuable information on the status in the field. The thesis project focused on the management perspective and developing metrics that align with the manager's information needs. To fulfill this task, the first chapter of the thesis contains a literature review on frameworks for performance measurement in businesses and organizations. Besides, the author elaborates on the design and research process and the characteristics of performance measures. The second theoretical chapter covers the Digital Oilfield. It details, what the industry understands under the Digital Oilfield concept, its objectives, and how different companies and professionals implemented it. The author also discusses the role of performance measures in the Digital Oilfield environment and presents examples for performance measurement systems in the field. Most oilfield performance measurement systems, described in the literature, work on a detailed, facility-level basis. Since this project aimed to create a holistic perspective of the oilfield, such a granular procedure was not feasible in the given timespan. Instead, the author developed a novel approach that shall yield metrics which align with the company's objectives. This approach rests on the strategic frameworks of the Balanced Scorecard and Hoshin Kanri. Its most critical component is the application of Critical success factors, which Rockart introduced and Parmenter described in detail. The practical chapter of the thesis describes how the author applied the designed methodology to define a set of performance measures for Digital Oilfield operations. In the first sections, the author discusses the characteristics, which performance indicators possess, and how he determined the Critical success factors. Based on this framework, the author defined a set of indicators, which he refined visually and structurally for the practical use. The next section of the chapter presents the final set of indicators. The final two sections discuss the data sources for the indicator calculation and the validation of indicators. Based on the results of the validation survey, the author concluded that the set of indicators is effective, and the workflow yields promising results.