What it is
In unconventional petroleum development — shale plays, tight oil and gas, and similar resources — the rock is heterogeneous at the scale of individual horizontal wells. Two wells drilled 1,500 feet apart in the same bench can deliver materially different production because of localized variations in total organic carbon (TOC), porosity, saturation, and geomechanical properties.
Sweet-spot mapping is the set of methods used to identify where the high-productivity intervals are, before horizontal-well placement, so that landing points and lateral trajectories target the rock that will actually produce commercially.
Why it matters
Sweet-spot heterogeneity is the defining economic variable of unconventional development. An operator drilling identical laterals across a homogeneous assumption of the rock will, on average, achieve the basin-average EUR (estimated ultimate recovery). An operator drilling laterals targeted at mapped sweet spots achieves meaningfully higher EUR per lateral foot and lower non-productive footage.
Methods used
- Seismic-derived attributes. Inversion, AVO, and other post-stack attributes correlated with regional productivity.
- Geochemistry. TOC maps from surface geochemistry and existing well data.
- Remote substance mapping. Direct hydrocarbon-saturation classification across the bench, used increasingly as a primary input.
- Microseismic monitoring. Post-completion, informs infill decisions.