In this, the second of a four-part series, we look at applications for multi-measurement methodologies within the reservoir. Although there are numerous MMI applications within the reservoir interval, four continuously come up most often in discussions with our clients:
- Fault and lineament mapping
- Fracture fairway detection
- TOC and brittleness characterization
- Production sweet spot identification
Fault (and, in shales, associated fracture network) detection is probably the most common. In a conventional reservoir, fault systems can play a key part in the mechanics of how hydrocarbons are trapped in clastic or carbonate horizons (for instance, by being juxtaposed against an impermeable and adjacent shale or salt horizon).
In unconventional reservoirs, the fault systems can be key determinants of where to (not) drill. In some basins (such as the Piceance or Sand Wash), the faults induce fracture networks that are associated with more productive, higher EUR wells. As a result, drill wells are often targeted near the fault systems. The image above is taken from Colorado’s Piceance Basin, with the hot colors denoting inferred fault and fracture systems (and the ‘sweet spots’ the E&P operator would want to target). The ‘hot’ magnetic anomaly is caused by groundwater that preferentially migrates along fault and fracture systems throughout the extent of geologic time, in the process causing magnetite-destructive alteration compared to the surrounding rock.
In other basins (such as Appalachia), the fault networks are generally avoided. E&P operators prefer to hydraulically fracture the reservoir using mechanical methods and to stay away from the fault and fracture networks in order to ensure the maximum hydraulic pressure is focused within the reservoir interval and not allowed to escape through the faults and fracture systems. In Appalachia, we’re using a combination of magnetic, gravity, hyperspectral, and radiometric measurements to identify and map fault networks from the basement to the surface.
We’re working on some other interesting things in Appalachia as well. One E&P operator has asked us to see if we can map the relative brittleness of the Marcellus Shale by simultaneously analyzing newly acquired gravity data along with existing 3-D seismic and well log data. More broadly, we’re also working to see if we can identify the geo-measurements that correlate with production and EUR (both for ‘good’ wells and ‘bad’, which we group according to similar completion status (e.g., lateral length, number of frac stages)). This analysis is similar to the geo-statistical work we’ve undertaken for other clients in other conventional basins (to read our geo-statistical case study about the Ventura Basin in the April 2012 edition of Hart’s E&P magazine, click here). We are hoping that we can combine – in a single methodology that analyzes all available G&G data – what the industry is effectively trying to do ‘attribute-by-attribute’ at present. If successful, this truly could be a game-changer when it comes to the E&P industry’s capabilities to detect sweet spots in unconventional shale reservoirs.
To learn more about the applications of multi-measurement methods throughout the geologic column, click here to watch the latest narrated slideshow from NEOS.