WaterTech 2015 Joe Riddell and Christian Nägeli · grid surfaces individually grid math to create...

WaterTech 2015

Joe Riddell and Christian Nägeli

April 20th – 22nd 2015

Agenda

1 Introduction

2CSM Overview and Workflow

3 Scale Independence

4Case Studies

5Conclusions

Introduction1

• Generation of a 3D CSM is the first thing we do on

all hydrogeology projects

• Even proposals benefit from leveraging available

data to refine scope and costs

• Field Program Planning & Execution

CSM Overview2

CSM – What is it?

Compilation of existing site information

• Collection of previously collected geological,

geotechnical, hydrogeological, and analytical

data for soil/groundwater

• Compiled and entered into a 3D Geomodel

• Geological structure and hydrogeologic regimes

are characterized

Tells the story of what we know

• Presents our current understanding of site

conditions, implications for contaminant

distribution

• Powerful for inferring geological features, data

gap analysis and field program planning

Data Compilation and Normalization

CSM – Why build a CSM?

Evaluate Multiple Hypotheses

• Data gaps can be systematically filled (a priori)

• Helpful in stakeholder communication with

client/regulators for approvals or scope changes

• Very useful for long-term sites and monitoring

Valuable reconnaissance for field staff

• Field staff start with a schematic of salient

geological features and understands the setting

• Drilling prognoses (if existing site data exists)

• Iterative, on-the-fly improvements to CSM can be

made during drilling program

CSM Development & Challenges

Data Normalization

• Difficult to normalize data (different sources/scale)

• Different data types

• Incomplete data sets (i.e., lacking well attributes)

Requires Experienced Analyst

• Requires earth scientist with understanding of

sedimentary processes, correlations &

hydrogeological processes

• Requires advanced supporting software tools

• Similar initial steps

• Development is

cumbersome and time

consuming

• No reinterpretation on the fly

• Many iterations of the

process

Traditional CSM Development

grid surfaces individually

grid math to create isopachs

cut cross sections and fence diagrams for pseudo 3D analysis

grid potentiometric surfaces and iso-concentration contours

create blanking files

CSM Development Workflow

Data Gathering

CSM Development

Field Program Numerical Model

Statement of problem and objectives

Data Formatting

Interpretation

Data Gap Analysis

• Work with capability

of 3-D software

• Use of other geo-

spatial platforms

• Tidy file management

• More efficient

iteration (on-the-fly)

Scale independence3

From Local Scale To Regional Scale

Value of Local Scale Data

Value of Regional Data

Case Studies4

4.1 Use of CSM for Hydrocarbon delineation

• Site with HC impacts

• Capitol Region

Bring in readily available information:

• Site topography

• Borehole coordinates and elevations (information gap requiring assumptions)

• Digital air photo of site

• AESRD & AGS information (raster, vector & even tabular mapping data)

• Data from historical reports (ESAR borehole logs)

• Analytical data for soil and groundwater

• Use geostatistical

interpolation

algorithms to

generate bounding

surfaces (top and

bottom) of

normalized layers in the CSM

• Generate geological

media volumes and

develop the hydrostratigraphic

framework

• Build water table

surface based on

historical monitoring

well data

4.1 Use of CSM for Hydrocarbon delineation

4.1 Data Gap Program

a) Based initially on soil

vapour screening to

produce a conservative

contaminated soil volume

b) View proposed

boreholes within context of

geology,

hydrostratigraphy, and

conservative

contaminated Soil volume

b) Refine contaminated

soil volume with analytical

borehole samples for remediation scoping

a)

b)

4.2 ¼ Section Hydrogeological Exploration

Desktop StudyProduction Well Installation/Optimization

• Concrete Plant / too expensive municipal

water supply

• Possible buried channel deposits

• Possible productive bedrock intervals (Horseshoe Canyon Fm).

• Preliminary model with public water well

data

• Identification of potential drilling targets,

static WLs, surrounding pump intake and

screened interval analysis

• Ongoing model updates during drilling

• Successful production well installation and stakeholder engagement

Promising channelized deposits


Project Site

Bedrock

Topography


• Most wells in the area installed in bedrock (2-5

igpm); target 50-75 igpm

• CSM identified gap (not recognized semi-

channelized pre-glacial deposits)

• Hydrogeologic exploration expanded to

overburden potential aquifer

Field drilling information improving CSM

• Bedrock borehole (BH) confirmed low yield

• Four additional BHs in pre-glacial sand and gravel

deposits delineated successful location for

Production Well

Not so promising yields of existing wells (all referred to centre of quarter section)


Pre-glacial gravel / sand potential aquifer “missed” by nearby wells


Pre-glacial sand

& gravel

Final result showing slightly channelized sheet-flood deposits of pre-glacial sand and gravel


• Isolated northern community relying on surface water

• Little to no existing site-scale data at project outset

• Used regional geology data to develop preliminary model

• Preliminary model used to identify potential aquifer targets

• 23 boreholes over 20 km2 area

• 6 Completed as Pumping wells installed within a well field

• Secured current and future water demand for Community

2 Public water well records (only 6 – 7 m BGS)

No depth to bedrock information

Limited subsurface data => Preliminary CSM

Test the Preliminary CSM

• Drilled to bedrock on nearly all test holes

• Establish bedrock topography (channel?)

• Collect down-hole geophysical data

• Drilled into bedrock on two deep test holes

• Evaluation of bedrock aquifer

Field activities guided by initial CSM, concurrent

field data collection, and 3D CSM updates

4.3 Community Scale Water Supply (20 km2)

Test Hole

Glaciofluvial

Channel

Initial Interpretation


Final Interpretation

Discrete poorly

connected channels

Flat Bedrock Topo

Poor Water Quality

3D Geomodel used to define channel thalweg and optimize well placement within well field


Conclusions

• Preliminary conceptual model was critical to

communicate with client and explain our approach

• CSM promoted effective decisions to continue the

drilling program and develop the appropriate aquifer

• CSM allowed effective interpretation of depositional

environment and aquifer geometries

• Aquifer response analysis benefited from CSM

• Geomodel serves as a platform for aquifer

management/monitoring and future exploration

activities


Proposed projects include major site infrastructure,

dewatering/production/injection wells, tailings management

areas, open pit construction etc.

Assessment objectives were to:

1. Increase understanding

2. Evaluate risk

3. Mitigate risk

3D Conceptual Site Modeling was used to synthesize available

data to evaluate and mitigate potential project interactions to groundwater quantity and quality

4.4 Dissolution Mining Project

Data gathering,

review and synthesis.

186 - water well records

with e-logs to determine

lithologies

8 - regional

groundwater studies

9 - Shallow groundwater

wells in the TMA

4.4 Development in 3D Software Environment

• Add additional e-log interpretation to fill gaps and reinterpret

on-the-fly

• Make manual adjustments to surfaces based on depositional

interpretation and stratigraphic principles until satisfied with

model

• Add aquifer parameters, hydrochemical & potentiometric data

4.4 Numerical Model

• Export of 3D CSM directly to

FEFLOW or MODFLOW

• Detail groundwater flow and

simulate contaminant

transport scenarios

• Collaboration and

communication between project Hydrogeologist and

modeler

• Design meaningful

monitoring and mitigation

5 10 25

50 100 200

300 400 500

5 years 10 years 25 years



• Proposed development includes two open pit areas, waste

rock disposal area

• CSM forms framework for the baseline assessment of

groundwater flow patterns, quantity and quality

• Numerical model to evaluate interactions between the

project and groundwater resources

• CSM used to develop effective monitoring and mitigation

measures to limit potential impact

• Large domain required for

EA domain (limit BC effects)• Geo-referenced structural

/bedrock geology maps

• Literature

• Coal exploration picks (x’s)

• Stantec boreholes ( ) K-testing

• DEM (LiDAR & Mine progression

plan

Key Aquifer

4.5 Building Hydrostratigraphy

• Gridded surfaces outside of 3-D environment

• Build depositional surfaces with hydrostratigraphic column & True Vertical

Thickness offset calculations

• Grid math to add the vertically offset surfaces to Key Aquifer (Blue)

• Erosional deposits specified based on drift thickness and surface

mapping of till and alluvium/colluvium

Conclusions5

• Scale Independent

• Communication (Clarity & Rationale Scope of Work)

• Efficient Workflow

• Value Added Field Programs

A sound understanding of the geological framework

leads to improved project understanding & deliverables

• Physical Hydrogeological characterization

• Aquifer response characterization & GW Exploration

• Contaminant delineation

Questions?

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