Basin simulation for complex geological settings

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Énergies renouvelables | Production éco-responsable | Transports innovants | Procédés éco-efficients | Ressources durables © 2 0 1 2 -IF P E n e rg ie s n o u v e lle s

Basin simulation for complex

geological settings

Towards a realistic modeling

P. Havé*, I. Faille, F. Willien

IFP Energies nouvelles

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0 1 2 -IF P E n e rg ie s n o u v e lle s

What is « Basin simulation » ? (1/2)

Improving subsoil knowledge by modeling its geological history

Modeling from the creation of the basin to know its present state

Qualitative and quantitative information about fluids in the porous media

Reducing risks and costs of the oil exploration

Where are hydrocarbons ?

How much oil is available in a trap ?

(3)

Direction Technologie, Informatique et Mathématiques appliquées GdR MOMAS – Marseille – 15-16 octobre 2012 © 2 0 1 2 -IF P E n e rg ie s n o u v e lle s

What is « Basin simulation » ? (2/2)

Typical geological scales

Time: From 10 to 400 MY

Length : 100 km

Depth : 10 km

Highly heterogeneous media : sand, clay...

Sediment

deposition

Burying - Compaction –

Temperature increase

Cracking – expulsion

- migration

Trapping into oil

and gas fields

(4)

Existing approaches : « simple geometry »

Structured grids

Conforming mesh with vertical pillars

Allows degenerated hexahedra

Parallel 3D code

Does not allow complex tectonic deformations

E.g. : fault displacements

Multi structured blocks

Sequential 2D code

Difficult to extend in 3D

Structured grid with

degenerated hexahedra

(5)

Why « Complex geological settings » ?

«««« Simple geometry »»»» areas are “

well”

known

« Complex geological » areas are promising

To push back peak oil

Recent discoveries in unexpected areas

Complex areas are difficult to understand without modelling

(6)

Examples of complex geological settings (1/2)

NE

HW Cutoff of 2.3 Ma Horizon

« simple »

« complex »

Extensive setting

(7)

Faults have an important impact on flow paths

Discontinuous model

Can juxtapose stratigraphically distinct layers

Jourde et al. (2002)

Berg and Skar (2006)

« Fault zone » : thin area around faults

Can define new barriers or shorten migration path

Fault network

Huge impact on pressure field

(8)

The challenge of « Complex »

A short research to market timing

2006 : first prototype

2012 : first commercial product

New 4D meshes

mixing 3D (media matrix) and 2D areas (faults)

Improved physics modeling

A wide range of geometric alterations

Fault flow : across and along

New schemes

For Stress, Darcy and Thermal models

Performance

(9)

A short research to market timing (1/2)

The choice of a C++ Framework : Arcane™

Co-developed since 2006 with CEA/DAM

Provide low level services

I/O, parallelism and network communications

Parallel data management :

Partitioning, load-balancing, checkpoint/restart...

Ensure good performance on parallel clusters

Tested with > 16k cores and > 10

9

cells

Domain decomposition parallelism : MPI, threads or hybrid of both

Task parallelism : to process a flow of (in)dependant

small

tasks

Plug-in architecture for sharing or extending base services

Mesh, Timeloop...

Numerics, Physics...

Arcane

Completion Application exit compute-loop Application initialization

Data set & mesh

building

Arcane Startup

(10)

A short research to market timing (2/2)

The choice of a C++ Framework : Arcane™

Speed up industrialization process

Debugging tools (TotalView integration, HYbrid Online Debugger for

Arcane), performance tracking, trace facilities...

High level approach :

abstract interface, embedded containers, C# binding

Supports Linux and Windows platforms

Extended for business features in ArcGeoSim™ project

Provide common facilities for research and commercial IFPEN

products (CO

2

sequestration, Enhanced Oil Recovery simulator...)

People focussed on their skills

Physics modeling

Numerical analysis

Computer Science

Integrated in a pre/post-processing environment : Open

Flow

or

Arcane Core

Geometry

CPG | Surface | SubMesh | AMR

Numerics

Schemes | Solvers | Algorithms

Physics

Thermodynamics | Hydrodynamics | Chemistry

Business

MultiPhaseFlow | ReactiveTransport | Wells

Specific Modules _{Specific Services} Application A rc G e o S im A p p lic a tio n Arcane Core

Geometry

Numerics

Physics

Business

Arcane Core

Geometry

Numerics

Physics

Business

Specific Modules _{Specific Services} Application A rc G e o S im A p p lic a tio n

Specific Modules _{Specific Services} Application

Specific Modules _{Specific Services} Application A rc G e o S im A p p lic a tio n

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Workflow Temis

Flow

V3

gOcad / Kine3D

Powered by Code Aster

ArcTem

pre

-

processing

Mesh validation

Data preparation

Powered by Open

Flow

Eclipse based environment

ArcTem //

(13)

CPG with degenerated hexahedra

“Evolutive Mesh” : kinematic driven geometry

Faults with 3D dynamic co-refinement

AMR (2010)

Voronoï approach

IXM Format (v4 - XDMF like)

Sub-meshes (mesh view)

1D and 2D variants

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Mesh increments given at each geological age

Increment types:

Sediment deposition : new cells appear and grow

Compaction and kinematic deformation : nodes move

Sliding along faults : non conforming mesh and surface co-refinement

Erosion : cells disappear or may change their type

Computation mesh is interpolated between two ages

Fault = sliding surface

(15)

Improved physics and robust numerics (1/5)

Compaction and fluid flow coupling

Compaction is the engine of the fluid flow

Coupled equations

Mass conservation, Darcy law

Vertical mechanic equilibrium

Elasto-plastic rheology

Finite volume schemes

Implicit formulation

Unknowns

Cell-centered Pressure (over-pressure)

Node-centered Vertical Constraint

Cell-centered Porosity

Challenges

Robust FV schemes for « div K∇ » operator

on very messy mesh

No more vertical pillar

Faults

Fault LGR L K σ K u L u σ K n

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Improved physics and robust numerics : Faults (2/5)

Faults

A fault is defined as a relation between 2 surfaces

The interactions between these two surfaces

have to be computed at each time step and

take into account gaps, overlaps and fault intersections

(Node→Face and Face→Face correlations)

Across fault flow

Fault properties associated to each face

Flux through juxtaposed faces

(17)

Improved physics : Faults (3/5)

Very permeable

media

Very impermeable media

Across fault flow

An academic test case

Increased water speed

due to connected

(18)

Improved physics : Faults (4/5)

Along fault flow

Flow parallel to the fault

Flow in a thin part of the medium (damaged zone)

Modeled using a surface flow on fault surfaces requires

Extended conservation equations

New pressure unknowns to discretize

Opposite flow surfaces connected through an across fault flow

Implemented using sub-mesh concept which defines a part of a mesh

(here codim 1) as a true mesh. Each mesh or sub-mesh has its own

connectivity.

(19)

Improved physics (5/5)

10km 40km 7km

Synthetic example

8 layers : sand and shale

8 faults

Overpressure and

water velocity

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Improved physics (5/5)

10km 40km 7km

Synthetic example

8 layers : sand and shale

8 faults

Velocity along fault

surfaces

(21)

Performance (1/3)

The target...

comparable

performances with legacy code on simple

geometry

and able to support complex geometry

weak scalability to aim our customers

optimized for 8-32 cores

ready for more

However, performances are a key element of the

strategy of that product.

(22)

Performance (2/3)

On simple geometry...

Reference legacy code

New product

Simple geometry,

Complex geometry

complex physics,

young

physics

10 years old optimized code

An overhead due to complex data structures but

More scalable

Major performance improvement will come from an

improvement of the linear solver scalability.

# procs

Durée (h:m:s)

Durée (s)

Scalabilité

Efficacité

Durée (h)

Durée (s)

Scalabilité

Efficacité

vs Visco

1

09:24:31

33871

1,0

100%

11,82

42549

1,0

100%

+26%

4

02:37:28

9448

3,6

90%

3,04

10953

3,9

97%

+16%

8

01:39:09

5949

5,7

71%

1,67

6018

7,2

88%

+1%

16

00:59:34

3574

9,5

59%

1,06

3803

11,3

70%

+6%

32

00:36:09

2169

15,6

49%

0,64

2297

18,8

58%

+6%

64

00:24:31

1471

23,0

36%

0,37

1337

32,3

50%

-9%

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Performance (3/3)

Dynamic fault aware partitioning:

Zoom on two sub-domains

(own + ghost)

And more...

Dynamic partitioning facilities

Allows to address a wider range of solvers (including GPU)

Tested up to 2048 cores (robustness test)

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