Use of barometric response to obtain in-situ compressibility of a coalbed methane reservoir

A theory is presented for calculating the constrained (matrix) compressibility for aquifers from responses to tides and changes in surface pressure when both gas and water are present. With this theory, a new method to determine matrix compressibility without a pump test is developed. The method is then applied to a coalbed methane well in the Piceance basin.