Abstract
Abstract We investigated fines movement through sandstone in-situ at the micrometre pore scale and studied the associated pore-scale mechanisms leading to formation damage. We used two in-situ techniques to accomplish this, namely nuclear magnetic resonance T 2 relaxation time (NMR) measurements (of pore size distributions) and high resolution x-ray micro-computed tomography (μCT; at high resolutions of (0.89 μm) 3 and (3.4 μm) 3 ). The μCT images showed the precise 3D location of the fines particles in the plug and demonstrated that initially pore throats are plugged, followed by filling of adjacent pore bodies by solid particles. These measurements in combination with traditionally used (indirect) permeability and production curve measurements and ex-situ SEM imaging enabled us to propose a new mechanistic pore-scale plugging model; furthermore we demonstrated that the amount of fines trapped decayed rapidly with core depth. We conclude that it is feasible to analyse formation damage in-situ by a combination of NMR and μCT measurements.
Highlights
Migration of colloids (r5 μm) and dispersed small solid particles (o100 μm) through a porous medium is a key problem in various fields as deposition of such particles can severely reduce permeability
The permeability (k) continuously and smoothly decreased with time (t) following a power law k1⁄4 3.94tÀ0.343, Pearson coefficient R21⁄4 0.996,; k1⁄4 2.701tÀ0.403, R21⁄4 0.978, and the permeability reduction was more significant for the higher barite concentration as expected, consistent with trends reported in the literature (Krilov et al, 1991; Asghari et al, 1995); 0.6
We observed formation damage caused by fines injection into sandstone plugs in-situ by μCT and nuclear magnetic resonance T2 relaxation time (NMR) measurements
Summary
Migration of colloids (r5 μm) and dispersed small solid particles (o100 μm) through a porous medium is a key problem in various fields as deposition of such particles can severely reduce permeability Areas which face this problem include hydrology, where the focus is on water production (McDowell-Boyer et al, 1986; Bradford et al, 2011; Torkzaban et al, 2007), geothermal engineering, where cold water is pumped through subsurface reservoirs to produce warm water (Mahmoudi et al, 2010; Rosenbrand et al, 2014, 2015), wellbore drilling (Byrne et al, 2007; Civan, 2007) and petroleum recovery, where water is injected to maintain reservoir pressure and mobilize additional hydrocarbons by viscous forces (Ahmed and McKinney, 2005; Iglauer et al, 2010).
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
