Quantifying the Results of Horizontal Multistage Development in Tight Oil Reservoirs of the Western Canadian Sedimentary Basin: Technical and Economic Case Studies From a Reservoir Evaluator’s Perspective

Abstract

Abstract Recent advances in horizontal drilling and multistage completion technologies have unlocked vast quantities of previously inaccessible oil reserves. Since 2006, thousands of horizontal multistage wells have been drilled into numerous low permeability oil reservoirs in the Western Canadian Sedimentary Basin including the Bakken, Cardium, Viking and Shaunavon formations. Early horizontal multistage wells had relatively short horizontal sections with two to four completion stages per well and have evolved over time to include wells in certain areas that have up to two mile horizontal sections and over 25 individual completion stages. Along with the technical advancements that have occurred recently, operators are actively seeking new reservoirs in which to apply them. This paper presents a brief historical look back at a few of the major areas that have been developed to date. Specifically, the light oil developments of the Bakken formation in Saskatchewan, Manitoba and North Dakota, the Cardium formation in Alberta, the Viking formation in Alberta and Saskatchewan and the Lower Shaunavon formation in Saskatchewan are studied in detail and comparisons drawn. Type curves are presented by vintage for each play showing the progression of advancing technology countered by operator desire to push the development into reservoir of diminishing quality. Specific technical metrics regarding initial production rates and decline rates are compared and contrasted. Average expected ultimate recoveries are estimated based on decline analysis and the authors experience completing detailed reserve evaluations for operators in their respective development areas. Based on the statistical study of performance to date and the estimates of ultimate recovery a type well based on current development is generated for each of the areas. Economic modeling based on the generated type wells and a comparison of the various development areas is presented using a number of financial and industry metrics. Despite vast differences in productivity and recovery per well between the plays, the economic analysis reveals that bigger is not necessarily better.