Implementation of Dynamic Neutron Radiography and Integrated X-Ray and Neutron Tomography in Porous Carbonate Reservoir Rocks

Miller Zambrano,Kaestner Anders,Emanuele Tondi,Fareeha Hameed,Lucia Mancini

doi:10.3389/feart.2019.00329

Abstract

The textural and geometrical properties of the pore networks (i.e. such as pore size distribution, pore shape, connectivity and tortuosity) provides a primary control on the fluid storage and migration of geofluids within porous carbonate reservoirs. These properties are highly variable because of primary depositional conditions, diagenetic processes and deformation. This issue represents an important challenge for the characterization and exploitation plan in this type of reservoirs. In this study, the complementary properties of neutrons and X-ray experiments are carried out to better understand the effects of pore network properties on the hydraulic behavior of porous carbonates. Neutrons have unique properties and are particularly suitable for this study due to the sensitivity of neutrons to hydrogen-based fluids. The used methodology combines dynamic neutron radiography (NR), integrated X-ray and neutron tomography (XCT, NCT), and computational fluid dynamics simulations (lattice-Boltzmann method) of porous carbonate reservoir analogues from central and southern Italy. Dynamic 2D NR images provide information regarding the fluid transport and the wetting front dynamics related to the effect of heterogeneities (e.g. fractures and deformation bands) at the microscale. The combination of NCT (dry and wet samples) and XCT (dry), generates more information regarding the effective pore space contribution to fluid flow. The fluid flow simulations generate information about the connected pore network and the permeability evaluated rock sample at saturated condition.

Highlights

Porous carbonate rocks constitute important reservoirs for water and hydrocarbons
Recent investigations of carbonate rocks have focused on evaluating the internal architecture and their impact on fluid flow in porous samples at the microscale by the integration of X-ray microtomography image analysis (Blunt et al, 2013; Cilona et al, 2014; Ji et al, 2015; Arzilli et al, 2016; Baud et al, 2017; Voltolini et al, 2017; Zambrano et al, 2017; Kaminskaite et al, 2019; Riegel et al, 2019) and computational fluid dynamics (Zambrano et al, 2018)
The last aim of this work is to investigate the fluid flow at saturated conditions which have been covered by performing computational fluid dynamics experiments

Summary

Introduction

Porous carbonate rocks constitute important reservoirs for water and hydrocarbons. The characterization in terms of fluid storage and migration of these reservoirs is challenging because of their petrophysical variability related to both depositional environment and subsequent diagenetic processes (e.g., dissolution, cementation, mineral replacement, deformation). Recent investigations of carbonate rocks have focused on evaluating the internal architecture and their impact on fluid flow in porous samples at the microscale by the integration of X-ray microtomography image analysis (Blunt et al, 2013; Cilona et al, 2014; Ji et al, 2015; Arzilli et al, 2016; Baud et al, 2017; Voltolini et al, 2017; Zambrano et al, 2017; Kaminskaite et al, 2019; Riegel et al, 2019) and computational fluid dynamics (Zambrano et al, 2018) Neutrons with their peculiar properties (such as ability to penetrate metals) and sensitivity to hydrogen (Schillinger et al, 2000), offer a valuable tool for such studies related to flow problems like capillarity-driven (e.g., Cnudde et al, 2008) or pressure-driven flow (e.g., Yehya et al, 2018). Several studies have used Neutron radiation images to characterize the porosity, moisture, and water absorption in different materials such as concrete (De Beer et al, 2005; Kanematsu et al, 2009; Zhang et al, 2010, 2011; Yehya et al, 2018), steel (Zawisky et al, 2010), building stones (Hameed et al, 2006, 2009; Cnudde et al, 2008; Zawisky et al, 2010; Dewanckele et al, 2014), porous asphalt (Lal et al, 2014), sandstones (De Beer and Middleton, 2006; Hall, 2013), clay-rock (Stavropoulou et al, 2019), dehydration of molding sand (Schillinger et al, 2011), and cultural heritage artifacts (Fedrigo et al, 2018; Schillinger et al, 2018)

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