The Second Bone Spring Sand is currently the second most drilled bench within the Delaware Basin. Some of the main struggles encountered by operators is determining the combined optimal well spacing, targeting, and completions design for a given bench. Moreover, to economically and efficiently develop any bench within the Permian, a strong understanding of reservoir heterogeneity is needed. Recent work has provided insight into the controls on Second Bone Spring Sand (SBSS) production and optimal development strategies. A key driver of well performance is reservoir architecture, and one must understand the spatial variability of their field area as it affects the overall development strategy that is ultimately deployed (i.e. completions design, well spacing, targeting, etc.). Furthermore, a deeper look into completions trends within the SBSS has closed the gap in optimizing dollars spent in relation to production gains.
The Permian Basin of southeast New Mexico and west Texas has been a highlight of North American oil and gas exploration, development, and production for decades. This basin is further sub-divided into the Midland and Delaware Basins (Figure 1), which are separated by the Central Basin Platform. The Delaware Basin is bounded to the east by the Central Basin Platform, to the west by the Diablo Platform, to the north by the northwest shelf and to the south by Marathon-Ouachita orogenic belt.
Formation of the Delaware Basin began with the Tobosa Basin (Galley, 1958) that existed from the Late Pre-Cambrian through the Mississippian, with compression and faulting during the Ouachita-Marathon Orogeny causing the Central Basin Platform to rise (Schumaker, 1992; Soreghan & Soreghan, 2013).
Climate during deposition in the Delaware Basin was generally arid, with the basin resting at approximately 5-10° north of the equator (Soreghan & Soreghan, 2013; Ziegler et al., 1997). Sediment is thought to have been sourced via aeolian transport as well as via fluvial systems (Fischer & Sarnthein, 1988; Soreghan & Soreghan, 2013).
Deposition in the Delaware Basin fluctuated between carbonate-rich highstand and silica-dominated lowstand conditions with high TOC mudstones forming farthest from the shoreline. This reciprocal sedimentation depositional history has led to mixed-lithology rock with highly variable facies, such as the Wolfcamp and Bone Spring Formations that are major targets of unconventional development today. The Leonardian Bone Spring Formation especially displays this lithologic alternation and is comprised primarily of three major siliciclastic members divided by carbonates that are named in order of increasing depth (Figure 2), in addition to regional members such as the Avalon and Harkey Mills Sandstone. This paper focuses on the middle siliciclastic member, the Second Bone Spring Sand (SBSS), which was deposited as a lowstand submarine fan system.