Predictability of Porosity and Permeability Alterations by Geochemical and Geomechanical Rock and Fluid Interactions

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThis paper presents improved models for interpretation, correlation, and prediction of the variations of permeability and porosity in petroleum-bearing rock, in which the pore topology is evolving by geochemical and geomechanical rock and fluid interactions during formation damage and stimulation processes. The permeability and porosity relationships considering pore evolution by precipitation and dissolution, and stress and temperature variation are developed. The present approaches are demonstrated and verified by analyzing a variety of reported data and shown to lead to accurate and functionally well behaving correlation. The applications demonstrate that the improved dynamic models accurately predict the measured porosity and permeability data. The associated analysis also lends itself to the physical interpretation of the variation of porosity and permeability in terms of the governing mechanisms.

Porosity–Permeability Relations for Evolving Pore Space: A Review with a Focus on (Bio-)geochemically Altered Porous Media

“…(9)) is based on experimental data. Civan (2000) fits values for γ (4.1 and 5.82) and β (2.96 and 3.89) observing that for the investigated data sets γ…”

“…Lai et al (2014) and Thullner (2010) both include a listing of relevant relations for chemical dissolution processes and biomass accumulation, respectively, but these lists are not exhaustive. Civan (2001) uses and references a wide variety of experimental studies to show the capabilities of the porositypermeability relation developed in Civan (1996Civan ( , 2000. This chapter will analyze a series of different relations, comparing everything from their origin to their application.…”

“…(9)). Civan (2000) shows that the parameters γ and β could be correlated with the coordination number, the number of pore throats connecting a pore body with its neighbors. This implies that, as long as the coordination number is constant, γ and β remain constant as well.…”

“…However, Civan (2000) also fits functions for γ and β in the case that the coordination number changes, e.g., for the data presented in Bhat and Kovscek (1999). The Civan relation is specifically intended to estimate the change in permeability during dissolution or precipitation (Civan 2001).…”

“…For Verma-Pruess and power-law relations, the values of the coefficients are given in the comments. In the last column, DFU, it is indicated whether the relation was derived (D), coefficients for the relation were fitted (F), or it was used by the authors (U) Civan (1996Civan ( , 2000Civan ( , 2001 Precipitation Modified Kozeny-Carman D, F Lichtner (1985) Precipitation Power law; η = 1, 2, 3, 8 U Tsypkin and Woods (2005) Precipitation Exponential D Verma and Pruess (1988) Precipitation Verma-Pruess; 1 ≤ η ≤ 6, 0.8φ 0 ≤ φ crit ≤ 0.9φ 0 D, F Xu et al (2004) Precipitation Verma-Pruess; 4 ≤ η ≤ 13, 0.88φ 0 ≤ φ crit ≤ 0.94φ 0 F Table 2 Comparison of the fields of application for the porosity-permeability relations presented in Sect. 3.…”