T236 Marcellus Shale Natural Gas Development: Geology, Geochemistry, and Engineering

Wednesday, 12 October 2011
8:00 AM - 12:00 PM
Room 101H-J

TIGHT GAS: FROM PORE-SCALE TO WELL DECLINE CURVE ANALYSIS

Paper number: T236-13
Program: Technical Sessions
Time: 11:10 AM – 11:25 AM

Authors

Abstract

Tight gas sands and gas shales are characterized by extremely low permeability of the rock. The efficiency of recovery operations depends on better understanding of the underlying pore-scale mechanisms of single and multi-phase gas flow. Micron-scale computed tomography and focused ion beam imaging techniques reveal the complexity of the 3D pore space geometry. A volume of tens of microns across can include a very rich diversity of minerals and grain sizes. The images also show how different the rock samples from different formations can be. Application of the pore-scale analysis to modeling gas flow into a fractured well leads to an analytically-described decline type curve. The curve consists of two regimes: a square-root-of-time decline in early production is followed by an exponential decline later on. Even though the underlying assumptions include great simplifications, production data from a number of gas shale wells verify the modeling results.