Comprehensive Study of the Charlson Oil Field, Williston Basin, ND

Abstract

AbstractThe objective of this study is to perform geological, petrophysical, geomechanical, decline curve, and economic analyses; a numerical reservoir simulation; and lastly a well and facility design for the Mission Canyon Formation of the Charlson Field of North Dakota. Essentially, the goal is to perform a broad start-to-finish analysis of the Charlson Field, while also determining the feasibility of a different development plan than what was used. It is important to note that the study is on a look-back basis as the field is mature and depleted.Geological and petrophysical analyses were performed using available well log and core data. A complete geomechanical and wellbore stability study was done as well. The well and facility design consists of casing, cementing, and separator design. These designs were established using historical designs, literature, and calculations. Numerical reservoir simulation was performed using simulation software and data obtained from the geological and petrophysical analysis. Decline curve analysis was performed using field production data. Lastly, economic analysis used historical oil prices, well cost data, and reservoir simulation production data.The results of the geological and petrophysical analyses helped to better understand the lithology, geology, and petrology of the Charlson Field. These results refined the area of study to areas of high production capability and obtained characteristics to use later in the study. The geomechanical analysis provided a Mechanical Earth Model, and a mud weight window that could be used to create drilling mud, and casing designs. The well design portion delivered casing and cement designs, that along with drilling mud designs created using the mud weight window, could have possibly helped alleviate casing failures seen in the field. The separator design provided an optimized separator system and operational conditions. The numerical reservoir simulation and decline curve analysis both provided production estimates for a development plan. The economic analysis was performed to determine the economic feasibility of the proposed development plan. The study determined that drilling another well in 1984 during the infill drilling of a separate well could have generated ~$18 Million net present value, with a rate of return of 18%. In addition, the well design could have helped alleviate casing failures in the Charlson Field. With the above conclusions, it is easy to see that even with the limited data used in this project, it is imperative to manage data for optimal results in any development.