What is Tight Gas?
In a conventional sandstone the pores are interconnected so gas is able to flow easily from the rock. In tight sandstones there are smaller pores, which are poorly connected by very narrow capilliaries, resulting in very low permeability.
Tight gas occurs in sandstones that have an effective permeability of less than 1 millidarcy. These relatively impermeable sandstones are reservoirs for considerable amounts of gas that are mostly uneconomical to produce because of low natural flow rates.
The outlook for increased production of gas from tight sandstones has been enhanced by the use of massive hydraulic fracturing techniques that create large collection areas in low-permeability formations through which gas can flow to a producing well.
A 3D volume of fracture intensity provides the ability to see how the predicted fracture intensity varies in depth/time and can be used to target zones to fracture. Often vertical stacks of fracture swarms are identified, which can be drilled using a vertical well.
- Increase Productivity and maximize the potential of a reservoir by identifying 'sweet spots' to drill and frac:
- Fracture density and orientation can be identified using wide-azimuth data, azimuthal anisotropy and fracture analysis, and multicomponent data
- Attributes such as lambda, mu, rho (LMR), multicomponent data and petrophysical inversion can be used to identify areas of high total organic content
- Thin beds can be identified using stochastic inversion
- Optimal areas for hydraulic fracturing can be identified from stress estimation
- The reservoir fractures can be monitored using microseismic or SeisMovie
- Reduce Risk:
- High pressure zones can be identified using multicomponent seismic and pore pressure prediction
CGG has the global expertise, experience and tecnology partnerships in place to create an integrated solution to understanding your tight gas reservoir.