Flow and transport of gases, CO2, NAPL and nano-particles in fracture systems on the local and

multiple-fracture scales

 Auli Niemi, Chin-Fu Tsang Fritjof Fagerlund, Zhibing Yang, Prabhakar Sharma,

Martin Larsson

UPPSALA UNIVERSITYDEPARTMENT OF EARTH SCIENCES

 

NGL ANNUAL SCIENCE MEETING

Oskarshamn, 7-8th of November 2013

  

MAIN INTEREST: study of flow and transport of

Gases, CO2, NAPL and Nano-particles in

fracture systems on the local and multiple fracture scales

 

LOCAL FRACTURE SCALE: Variable-aperture single fractures;

Complex fractures (with internal structures); Fracture zones

 

MULTIPLE FRACTURE SCALE; Fracture intersections;

Fracture networks – sparse; Fracture networks – dense

 

Flow and Transport•Gases; relative permeability, capillary pressure effects, etc.•CO2: added effects of phase change, solubility, dense brine with dissolved CO2, possible presence of mixture gases, fluid immobilization and entrapment etc.

•NAPL: multiple components and multiple phase effects, fluid immobilization and entrapment, interface characterization, interface mass transfer, dissolution etc.

•Nano-particles: pore-scale effects, effect of roughness of fracture surfaces, mixing of solutes, colloids, effect of unsaturated fractures (can be coupled with gas injection), etc.

•Characterization of trapped fluids (NAPL or CO2) using, e.g., partitioning tracer techniques

Outline

• Examples of our recent/ongoing work on example topics; CO2 geological storage, solute and NAPL transport in fractures and nanoparticle transport

• Possibilities for NGL

Geological storage of CO2 CO2

> 8

00 m

Several kilometers

Supercritical CO2Brine

A sufficiently impermeable seal (cap rock)

A sufficiently permeable reservoir rock

How is CO2 stored in the deep aquifer?

How is CO2 stored in the deep aquifer?

CO2

CO2 gets physically trapped beneath the sealing cap-rock and low permeability layers

How is CO2 stored in the deep aquifer?

CO2 gets trapped as immobile isolated residual ’blobs’ in the pore space

CO2

CO2 gets physically trapped beneath the sealing cap-rock and low permeability layers

How is CO2 stored in the deep aquifer?

CO2 gets trapped as immobile isolated residual ’blobs’ in the pore space

CO2 CO2 gets physically trapped beneath the sealing cap-rock and low permeability layers

CO2 dissolves into water

How is CO2 stored in the deep aquifer?

CO2 gets trapped as immobile isolated residual ’blobs’ in the pore space

CO2 CO2 gets physically trapped beneath the sealing cap-rock and low permeability layers

CO2 dissolves into water

CO2 converts into solid minerals

CO2 Geological Storage Ongoing EU FP7 projectsMUSTANG – large-scale integrating project for quantifying Saline Aquifers for CO2 Geological Storage (2009-2014)Panacea – project focusing on long term effects of CO2 Geological Storage (2012-2014)TRUST – project continuing and expanding the field experiment of MUSTANG (2012-2017)CO2QUEST – project focusing on effect of impurities of CO2 stream (2013- 2016)

Pre-feasibility studies in Sweden

financed by the Swedish Energy Authority

SwedeStoreCO2; to look at possibilities for a pilot scale injection experiment in the Swedish territory

BASTOR; to look at possibilities to store CO2 in the Baltic Sea region

Test sites

MUSTANG is a large-scale integrating EU FP7 R&D project (2009-2014), with 19 partners and 25 affiliated organizatons (coordinated by Uppsala University)

Objective: to develop methodology and understanding for the quantification of saline aquifers for CO2 geological storage

7 field sites includingone deep injection experiment and one shallow injection experiment of CO2, as well as strong laboratory experiment, process understanding and

modeling components

Webb-site : www.co2mustang.eu

MUSTANG project

Heletz deep CO2 injection experiment

Scientifically motivated CO2 injection experiment of scCO2 injection to a reservoir layer at 1600 m depth, with sophisticated monitoring and sampling

CO2 injection experiment

Objectives

• To gain understanding and develop methods to determine the two key trapping mechanisms of CO2 (residual trapping and dissolution trapping) at field scale, impact of heterogeneity• Validation of predictive models, measurement and

monitoring techniques

wells for field experiments

injection-withdrawal of scCO2 and brine

zone of residual trapped scCO2

1. 2.

Determine in-situ residual and dissolution trapping parameters

Reduced influence of formation heterogeneity

scCO2, brine & tracers

sc CO2

push-pull dipole

Heterogeneity affects migration and trapping

Hydraulic tests Thermal tests Tracer tests

residual trapping

residual trapping

residual & dissolution trapping, (& interfacial area)

CO2 Geological Storage Ongoing EU FP7 projectsMUSTANG – large-scale integrating project for quantifying Saline Aquifers for CO2 Geological Storage (2009-2014)Panacea – project focusing on long term effects of CO2 Geological Storage (2012-2014) (www.panacea-co2.org)

TRUST – project continuing and expanding the field experiment of MUSTANG (2012-2017)(http://trust-co2.org)CO2QUEST – project focusing on effect of impurities of CO2 stream (2013- 2016) (www.co2quest.eu)

Pre-feasibility studies in Sweden

financed by the Swedish Energy Authority

SwedeStoreCO2; to look at possibilities for a pilot scale injection experiment in the Swedish territory

BASTOR; to look at possibilities to store CO2 in the Baltic Sea region

CO2 Geological Storage Ongoing EU FP7 projectsMUSTANG – large-scale integrating project for quantifying Saline Aquifers for CO2 Geological Storage (2009-2014)Panacea – project focusing on long term effects of CO2 Geological Storage (2012-2014)TRUST – project continuing and expanding the field experiment of MUSTANG (2012-2017)CO2QUEST – project focusing on effect of impurities of CO2 stream (2013- 2016)

Pre-feasibility studies in Sweden

financed by the Swedish Energy Authority

SwedeStoreCO2; to look at possibilities for a pilot scale injection experiment in the Swedish territory

BASTOR; to look at possibilities to store CO2 in the Baltic Sea region

Possibilities to store CO2 in Sweden/Baltic•two feasibility studies 2012-2013, financed by the Swedish Energy Authority •SwedeStoreCO2; to look at possibilities for a pilot scale injection experiment in the Swedish territory •BASTOR; to look at possibilities to store CO2 in the Baltic Sea - so far financing by Finland and Sweden - contact person Per Arne Nilsson, PanaWare

Erlström et al, 2011 Vernon et al, 2013

NGL related questions – CO2 storage

• Integrity of the sealing cap-rock is crucial for the performance of the storage

• Need to understand the characteristics of fractures and fracture zones possibly intersecting the cap-rock

- flow through existing fractures and the related hydro-mechanical-chemical processes (opening/sealing of the fractures)

- possible creation of new fractures and re-activation of existing fractures/fracture zones due to mechanical effects

• NGL would provide opportunities observing gas/multiphase flow and trapping as well as brine migration in real fractures

Chemical alterations of caprock fracture fractures when brine saturated with CO2 flowing throuh

Hydro-thermo-mechanical effects

CO2 (supercritical and gaseous) flow through caprock fractures ; comparison of laboratory experments to natural analogue sites

Gouze et al, 2012

Edlmann et al

www.co2mustang.eu

Solute Transport in Fractures- study of flow-wetted surface as a function of

fracture aperture statistics

Larsson, M. et al (2013) A new approach to account for fracture aperture variability when modeling solute transport in fracture networks WRR 49(4), Pp. 2241-2252  

Larsson et al (2012) A study of flow-wetted surface area in a single fracture as a function of its hydraulic conductivity distribution WRR 48(1)DOI: 10.1029/2011WR010686  

Solute Transport in Fractures- determining of flow-wetted surfacefrom SWIW tests

Larsson, M et al (2013), Understanding the effect of single fracture heterogeneity from single well injection withdrawal (SWIW) tests. Hydrogeology Journal, DOI 10.1007/s10040-013-0988-x.

the specific flow-wetted surface, can be determined by matching the observed breakthrough curve for a heterogeneous fracture to that for a homogeneous fracture with an equivalent property parameter.

NAPL Transport in Fractures

23

ReleaseReceptor

Dissolved plume

Trapped residual blobs in fractures DNAPL pool in

dead-end fractures

GW flow

Fractured bedrock

Two fundamental processes:Fluid displacement (How DNAPL migrates)Interphase mass transfer (How DNAPL dissolves)

Variable-aperture fracture

bg

φ

aperture

NAPL Transport in Fractures

• Modeling of NAPL infiltration and dissolution in heterogenenous fractures, develop a general approach for flow and dissolution

• How does fracture roughness influence NAPL distribution and the dissolution process?

• Estimation of NAPL presence from observations of dissolved concentrations in the water

• What fracture geometries lead to fast dissolutions and what geometries make dissolution difficult?

• entrapment and dissolution in heterogeneous fractures

NAPL Transport in Fractures

Yang, Z et al (2012) Jour Cont Hydrol, 133:1-16. Yang, Z. et al (2012)  WRR  48, W09507. Yang, Z. et al (2013) Two-phase flow in rough-walled fractures: Comparison of continuum and invasion-percolation models. WRR 49(2) Pp 993-1002

DNAPL dissolution experiment

26

Light transmission systemAnalog fracture cell

Horizontal (cm)

Ve

rtic

al (

cm)

4.4 8.8 13.3 17.7

4.4

8.8

13.3

17.7

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Ve

rtic

al (

cm)

Horizontal (cm)4.4 8.8 13.3 17.7

4.4

8.8

13.3

17.7

Aperture field, mm

Entrapped TCEInitial condition for DNAPL dissolution

Yang, Z et al (2013) Dissolution of dense non-aqueous phase liquids in vertical fractures: Effect of finger residuals and dead- end pools. Journ Cont Hydrol Vol:149, Pp 88-99

Nanoparticles (NPs)

Use of nanoparticles is accelerating in a wide range products & technological applications Toxicity and transport behaviour in the environment largely unknown, particularly in complex media such as fractured rocks

Particles can act as carriers of other contaminants, including e.g. radionuclides Extreme surface area per unit weight:

extreme capacity for surface reactions different behaviour than larger particles

2 mg, aggregated

2 mg, dispersed

Critical to understand the mechanisms of NP transport & mobilization in fractures Particle interactions with both rock surfaces and other contaminants Particle-mediated transport e.g. from nuclear waste repository? Density-driven flow, heterogeneity & channelling

NP transport in fractures

saturated system

unsaturated system

Altered transport behaviour in the presence of a gas phase NP attachment at the liquid-gas interfaces

computerrelay / control unit

background fluid pump

injection fluid pump

camera

light panel

fracture replica

outflow

Dark box

Experiments & laboratory at UU

Light-transmission system to study 2D flow & transport processes – quantification of aperture, concentrations & fluid saturations Experiments in well-characterized, variable aperture fractures

USE OF NGL FACILITY

•For local scale; selection of different types of fractures, complex fractures, and fracture zones in the Äspö tunnel

•For multiple fracture scale; selection of different types of fracture intersections, sparse fracture networks and dense fracture networks in the Äspö tunnel

•Study at locations at different depths from close to surface to 460-m depth

•Study at different scales

•Study of multiple locations to explore effects of spatial heterogeneity

•Use of Äspö tunnel as sink by injection into rocks and observing emergence in the tunnel (and also possibly land surface)

RELEVANT ONGOING PROJECTS

CO2 geological storage•Four major EU FP7 projects, as coordinator or WP leader; MUSTANG 2009-2014, Panacea 2012-2014,

TRUST 2012- 2017, CO2QUEST 2013-2016

•Two pre-feasibility studies investigating CO2 geological storage in Sweden/Baltic; SwedestoreCO2 and Bastor, both funded by Energimyndigheten

•Research Councils (VR) strategic funds for CO2 research (2011-2014)

Deep hydrogeology of fractured rocks• Coupled effects in deep hydrologelogical systems, funded by SGU (2013-2015)

Some of the fracture studies presented above were funded by earlier FORMAS (flow welled surface analyses) and by VR (NAPL transport) projects

Thank you for your attention !