Methodology to Optimize Completions in the Mesaverde Formation, San Juan Basin, New Mexico

Abstract

Abstract Results of a recent major field study are used to define the optimum stimulation method for the layered, low permeability, naturally fractured Mesaverde formation in the San Juan Basin of New Mexico. Several stimulation methods are discussed and evaluated with respect to reservoir properties, production response, specific treatment characteristics, and well economics. The field study focused on the following objectives:The development of stimulation treatment methods for geographic areas where production is controlled by matrix permeability, and for areas where production is controlled by extensive natural fracturingCreating a method for determining the degree of natural fracturing present in any particular well location utilizing only historical production and pressure data.Determine if a well can be economically stimulated to drain the Mesaverde reserves on existing well spacing at the current gas prices.Assess the effectiveness of various treatment diagnostic tools, such as radioactive tracers and pressure monitoring, in the evaluation of fracture efficiency, geometry, proppant placement and distribution as well as possible communication between stages, and the percentage of each pay interval stimulated. Introduction The Mesaverde Group (Point Lookout, Menefee, Cliffhouse intervals) was deposited in the Upper Cretaceous period and is present throughout many of the Rocky Mountain basins. This study focuses only on the Mesaverde in the San Juan Basin of New Mexico (Figure 1). The Estimated Ultimate Recovery (EUR) for the Mesaverde in the San Juan Basin is approximately 13 trillion cubic feet (TCF) of natural gas, making it the second largest gas field in the United States. Since 1950, approximately 8.6 TCF has been produced from the Mesaverde Currently there are 5,100 Mesaverde wells producing a total of 600 million cubic feet of gas per day (MMCF/D). There are 1.8 million productive acres of Mesaverde in the San Juan Basin. This field study was initiated due to the difficulty in relating producing well behavior to open hole log analysis in the Mesaverde Wells with very similar log responses had extremely variable cumulative production histories. A study was therefore outlined to investigate the relationships between reservoir quality, type of completion, and well performance. Mesaverde Geology The Mesaverde formation is typically 600 – 800 feet in gross thickness when including the Point Lookout, Menefee, and CIiffhouse intervals. The Lewis Shale can be considered part of the Mesaverde Group and, if so, can nearly double the total formation thickness. However, due to the limited number of completions and short production history, the Lewis shale was not included in this study. The mid-point depth of the Mesaverde formation ranges from 5,000 to 5,500 feet. The most prolific Mesaverde interval, the Point Lookout, is located at the bottom of the section and is generally 125 – 175 feet in gross thickness. It consists of a massive sandstone, generally 40 – 60 feet thick, and several 2 – 5 feet thick sandstones. P. 173^