Tight Gas Reservoirs Low Permeability Reservoirs The main contributor of unconventional gas in the US

By definition any reservoir with a permeability of.1 md or less is a tight gas reservoir. Defined by the NGPA of 1978 This is matrix permeability Most have much less perm,.01 or less

Not all tight gas reservoir act the same Very low matrix perm w/ natural fractures low matrix perm wo/ natural fractures Gas shales used to be listed as tight gas

By Definition Tight-Gas Reservoirs are Anisotropic..1 md Permeability will not produce economically. Formation must be Naturally Fractured and/or Hydraulically Fractured Which gives them directional Permeability.

K max K min Drainage in an Anisotropic Reservoir

Traditional Methods for finding Anisotropy Oriented Cores Best method to find direction of anisotropy Multi-well Interference Tests Can find values for K max and K min Also the direction The low perm makes these test very hard to run unless the spacing is very tight

Alternative Methods for finding Anisotropy Find K eff & K min Then use

Methods to optimize production in Tight-Gas Reservoirs Horizontal Drilling Regional Fractures Multi staged Frac Jobs Infill Drilling All Reservoirs with large spacing

From a presentation 11 years ago Within the next 10 years gas demand in the United States will increase from 21 tcf to 30 tcf of gas annually Today the U. S. Produces 18 tcf of gas annually