Discussion on a New Methods for the Characterization of the Swelling and Compression in Porous Rocks in Oil and Gas Reservoirs

Abstract

It is always controversial when one discusses the best way to calculate the stress in porous media and whether the porosity of rock can only be used to correlate the rock pore swelling coefficient and skeleton compression coefficient. After summarizing and analyzing the arguments of these two problems, the authors found that the main causes of disputes were caused by confused concepts, unclear understanding of engineering and mechanics, and wrong mathematical derivation. The authors proposed that Terzaghi’s formula was wrong, and it was impossible to correlate rock pore swelling coefficient and rock skeleton compression coefficient only by rock porosity. Meanwhile, the paper put forward six coefficients, including the rock swelling coefficient, the rock pore swelling coefficient, the rock permeability swelling-increase coefficient, the rock compression coefficient, the rock pore compression coefficient, and the rock permeability compression-decrease coefficient, and also given their physical meanings and expressions, which can solve the confusion of the characterization of swelling and compression features in porous rocks.

AAPG Datapages/Search and Discovery Article #130002© Petroleum Drilling Techniques, Issue 3, 2018