The Delaware Basin, the western sub-basin of the Permian Basin, is located in west Texas and southeast New Mexico. The Delaware Basin is rich in resource with a mix of organic shale and tight sand reservoirs. The focus of this presentation is the quartz-rich Avalon shale, part of the upper Bone Spring Formation. The self-sourcing Avalon shale in the northern half of the Delaware Basin can be subdivided into three zones based on sequence stratigraphy: upper, middle and lower hemi-pelagic shale packages bifurcated by carbonate debris flows. The three distinct Avalon zones have well-defined core development areas that migrate spatially across the basin and at places overlap, enhancing the resource density.
The initial Avalon exploration well in Salado Draw was drilled in 2012. A robust formation evaluation program was conducted which included vertical and lateral logging suites, conventional core, side-wall core, well-site drill cutting analysis, and post-drill geochemical analysis of headspace gas, mud gas, and produced liquids. Ultimately, petrophysical logs plus well-site cutting and gas (C1/C5 ratio) analysis were used to identify the optimal landing zone.
Two years after the original discovery well was completed, drilling of a series of multi-well pads began at 80-acre spacing, moving eastward toward the discovery well. The pad immediately adjacent to the discovery well was the site of an extended surveillance project designed to address completion, depletion, and spacing considerations. Data acquisition included: A micro-seismic survey designed to identify the SRV characteristics of a multi-well zipper frack, define the hydraulic fracture geometry, and look for evidence of interference between wells; an elemental cuttings analysis for lithology calibration; a 3D seismic survey to ensure lateral placement within the target interval for the length of the boreholes; and a retrievable fiber optic cable was run in three wells, two of which are adjacent to each other and within the microseismic survey, to record the potential communication between wells and production contribution along the laterals (Figure 1).
This integrated study ultimately refined our optimal spacing and completions designs to maximize hydrocarbon recovery. We present the results of the microseismic, fiber optic, and geochemical surveys conducted at these development wells and share adjustments made to the point-forward development strategy for this interval in Salado Draw in order to optimize resource capture and capital efficiency.
