33rd IEAEOR Syypmposiumiea-eor.ptrc.ca/2012/assets/s2/4 - Rousseau_Session 2_SLIDES.pdf · Introduction 4/5 Brief state of the art M bilit t lMobility control HMWSP considered as

3333rdrd IEAEOR SymposiumIEAEOR Symposiumy py pA u g u s t 2 6 ‐ 3 0 , 2 0 1 2

presenter: Hydrophobically Modifiedpresenter:D. Rousseau

Hydrophobically Modified Polymers for IOR: Controlling Injectivity Through Thickening

authors:G. Dupuis (Poweltec),D Rousseau (IFP Energies nouvelles)

Ability and/or Flow‐induced Gelation

D. Rousseau (IFP Energies nouvelles),R. Tabary (IFP Energies nouvelles),B. Grassl (IPREM‐EPCP)

Session 2: Theme BMonday August 27thy g

Introduction 1/5Context: polymers for mobility control and permeability reduction

polymers for mobility control(polymer flooding, SP, ASP)

l t b t ff ti polymer

oiloil

polymers to be more cost-effective(optimum viscosity / concentration)

polymers to be more stable(temperature, salinity, mech. degradation) inj. well

polymerinjectionwater

injectioninj. well(temperature, salinity, mech. degradation)

minimum adsorption is required

polymers for permeability reduction polymers for permeability reduction (well treatments ─water shutoff, injection profile control─ , conformance control) polymers to be more stable

(temperature, salinity, mech. degradation) controlled adsorption or controlled in-situ gelation

is requiredDi ti t P bilit R d ti bilit i

2 33rd IEAEOR Symposium33rd IEAEOR Symposium – August 26-30, 2012

Disproportionate Permeability Reduction ability is advantageous

Introduction 2/5HMWSP

Hydrophobically Modified Water Soluble Hydrophobically Modified Water Soluble Polymers (HMWSP)Polymers (HMWSP)

polymers with hydrophilic backbones bearing hydrophobicpolymers with hydrophilic backbones bearing hydrophobic units capable of creating physical bonds (hydrophobic

nanodomains) between each other ("associative" polymers)

hydrophobic nanodomain

C hydrophobic side-group

hydrophilic backbone


Introduction 3/5Advantages of HMWSP

Thickening agents (mobility control) sharp increase of viscosity above "caccac"

(Pa.

s) HMWSP

less chemicals required for a given mobility reduction high salinity : preservation/increase of viscosity shorter chains (~low Mw) Vi

scos

ity (

WSP

increased resistance to mechanical degradationConcentration (g/mL)

Permeability reducing agents (well treatments, conformance control)

"multilayer" adsorption on surfaces or flow-induced gelation in porous media marked and stable permeability reduction

WSP

4 33rd IEAEOR Symposium33rd IEAEOR Symposium – August 26-30, 2012HMWSP

Introduction 4/5Brief state of the art

M bilit t l Mobility control HMWSP considered as mobility control agents since ~1980 (Exxon Mobil, Chevron,

Dow Chemical – reviews by Taylor and Nasr-el-Din 1998 & 2007)

f ff C OOC ( ) ( renewed interest in the past years: first offshore pilot by CNOOC (~2007) (BoHai bay, China),

HMWSP were selected thanks to their satisfactorily behavior (viscosity) in the available

M bilit t l d i d th f t l

satisfactorily behavior (viscosity) in the available brines: mixture of see water, soft water and produced water with specific salinity/hardness

Mobility control and in-depth conformance control feasibility study for heavy oil in western Canada (2012) (from CNOOC)(from CNOOC)

Well treatments Halliburton (Eoff, Dalrymple & Reddy): patents,

publications and significant successes in field li ti ("W t b" )


applications ("Waterweb" process)

to date, HMWSP remain mainly used for well treatment operationsto date, HMWSP remain mainly used for well treatment operations

Introduction 5/5Motivations & objectives of the present study

Our previous works Synthesis and characterization of an extensive set of HMWSP and WSP with

identical hydrophilic backbones11

enables "true" comparative assessments between HMWSP and WSP Flow in porous media of dilute HMWSP solutions22

(to minimize the role played by "rheology" and to focus on adsorption) high Resistance Factors due to adsorption of minority polymeric species high Resistance Factors due to adsorption of minority polymeric species minority polymeric species can be removed by proper pre-filtration procedure

(also likely through optimization of the synthesis process)

The present study: flow in porous media of semi-dilute HMWSP solutions viscosity in the range of viscosity for mobility control applications

filt ti i d t i it i ( h ibl ) pre-filtration in order to remove minority species (as much as possible) impact of HMWSP rheology on their propagation in porous media


11 : G. Dupuis, et al., Anal. Chem., 2009, 8181, 8993–9001.22 : G. Dupuis, et al., SPE Journal (vol. 1616--11, March 2011 – SPE-129884-PA).

Outline

Introduction Introduction

Polymers and aqueous solution properties

M b filt ti Membrane pre-filtration

Coreflood experiments

Summary


Outline





Summary



" t d d b i " Polymers studied: Sulfonated-PAMwith Mw = 1.3-1.4 106 g/mol WSP: 20 mol-% AMPS, 80 mol-% AM

HMWSP 5 l % AMPS 94 5 l % AM 0 5 l0 5 l % AMC12% AMC12

"standard brine":20 g/L NaCl

HMWSP: 5 mol-% AMPS, 94.5 mol-% AM, 0.5 mol0.5 mol--% AMC12% AMC12

Relative viscosity

HMWSPWSP

HMWSPWSP

Relative viscosity aimed : r0 ~ 20 WSP

= 24 5

Aimed viscosityAimed viscosity

r0 = 24.5

Cp = 9.8 g/L

HMWSPFiltered solutions used for

coreflood experimentsFiltered solutions used for

coreflood experimentsr0 = 17.8

Cp = 3.4 g/L


Outline





Summary


Membrane pre-filtration

HMWSP Rm curve

S

-2- Channels opening

-3- Gel filtration

HMWSP Rm curve

S

-2- Channels opening

-3- Gel filtration

2-steps pre-filtration on 3µm Millipore-MF

b

HMWSP BT curve

WSP BT curve

WSP R

-1- Gel initiationHMWSP BT curve

WSP BT curve

WSP R

-1- Gel initiation

membranes: 30 s-1 and 3 s-1

WSP Rm curve

HMWSP TOC C/C0

WSP Rm curve

HMWSP TOC C/C0

STEP 2 (3 s-1)

WSP: good filterability HMWSP: complex behavior

"gel filtration" process with channels openning


g p p g 100% HMWSP concentration in the effluents (TOC) "acceptable" filterability"acceptable" filterability

Outline





Summary


Coreflood experiments 1/6 Experimental conditions and procedures

SiC (silicon carbide) granular packs 3 permeabilities investigated

SiC grain size d (µm) 5050 8080 150150SiC grain size, dg (µm) 5050 8080 150150

Permeability, k (10-12 m²) 1.0 1.0 ±± 0.10.1 2.5 2.5 ±± 0.10.1 11.0 11.0 ±± 0.50.5

Porosity, (%) 41 41 ±± 0.50.5 41 41 ±± 0.50.5 41 41 ±± 0.50.5y, ( )

Hydrodynamic pore throat radius, rp (µm)5.0 5.0 ±± 0.50.5 8.0 8.0 ±± 0.50.5 17 17 ±± 11

/815.115.1 , krr cpp

core holder with intermediate pressure taps: P measured on 3 sections "external damage" and "in-depth propagation"

E S1 S2

flow

direction

E S1 S2

flow

direction


1 cm

0 cm 5 cm 9 cm

10 cm1 cm

0 cm 5 cm 9 cm

10 cm

Coreflood experiments 2/6 Experimental conditions and procedures cont'd

Injection conditions 100% standard brine saturation T = 30°C fixed initial wall shear rate (velocity gradient) : wall = 15 s-1

(provides only an estimation of the shear rate) flow rates: Q = 2 to 7 mL/h or interstitial velocities: ui = 0.7 to 2.3 m/day

.

pipwall rurSQ /4)/(4

Procedure initial permeability determination

Q i y

p y polymer injection @ Q mobility reduction: Rm (or RF) = Ppolymer / Pbrine_initial

brine injection @ Qbrine injection @ Q brine injection @ various flow rates "irreversible" perm. reduction: Rk (or RRF) = Pbrine_final / Pbrine_initial

estimation of the polymer adsorbed thickness:


estimation of the polymer adsorbed thickness: h)1( 4/1 Rkrph

Coreflood experiments 3/6 WSP in a 1 Darcy core

BT curveBT curve

E S1 S2

Expected behavior: Rm ~ r0, quick breakthrough slight increase on section E: entry-face effect


Coreflood experiments 4/6 HMWSP in a 1 Darcy core

Gel initiationGel propagationon section S1

Pressure transducerout of range





Gel initiationon section E

on section S1Gel initiationon section E

on section S1Gel initiationon section E

on section S1

E S1 S2E S1 S2

up to 1 25 PVI: Rm @ 1 9 PVI: gel propagation up to 1.25 PVI: Rm ~ r0

viscous front propagation (& likely monolayer adsorption)

@ 1.25 PVI: ~103 Rm on section E, Rm on S1 and S2

@ 1.9 PVI: gel propagation on section S1 not (only) an external filter-cake


@ 1.25 PVI: 10 Rm on section E, Rm on S1 and S2 our interpretation = flowflow--induced gelationinduced gelation significant amount of polymer retained in the gel

≠ ≠ as in the diluted as in the diluted regime! (with regime! (with

minority species)minority species)

Coreflood experiments 5/6 HMWSP in cores with variable permeability

Gel initiation

k = 1 Darcy; rP = 5 µm

Gel initiation

k = 1 Darcy; rP = 5 µm 2.5 and 11 D cores: no flow-

induced gelation (up to 20 PVI)initiation

k = 2.5 Darcy; rP = 8 µm


E

initiationk = 2.5 Darcy; rP = 8 µm


E

experiments were all performed at the same initial wall shear rate:wall = 15 s-1.

flow induced gelation flow induced gelation seems to be triggered byseems to be triggered by

wall

Gel initiation on section E









seems to be triggered by seems to be triggered by "confinement" (pore "confinement" (pore size) rather than by size) rather than by hydrodynamics:hydrodynamics:5 µm < r5 µm < r CC < 8 µm< 8 µm

Gel propagation on


S1Gel propagation on


Gel propagation on


S1

5 µm < r5 µm < rppCC < 8 µm< 8 µm

(kinetics aspects remains to (kinetics aspects remains to be studied in details)be studied in details)


Gel propagation on section S1



be studied in details)be studied in details)

Coreflood experiments 6/6 Irreversible permeability reductions

WSP (k = 1 Darcy)WSP (k = 1 Darcy)WSP (k = 1 Darcy)

HMWSP (k = 2.5 Darcy)HMWSP (k = 2.5 Darcy)HMWSP (k = 2.5 Darcy)

S1S1

...

Permeability reduction (Rk) of HMWSP can be assessed only when no gel is formed

HMWSP adsorption = moderated to low: hHMWSP < h

WSP

pre-filtration was efficient to remove "minority species"


flow-induced gelation does not seem to be induced by the build-upof adsorbed HMWSP multilayers

Outline





Summary


Summary

This study was performed on 1 particular class of HMWSP, with "low" Mw This study was performed on 1 particular class of HMWSP, with "low" Mw ((101066 g/molg/mol) and "high" hydrophobe content () and "high" hydrophobe content (0.5 mol0.5 mol--% monomers with C12% monomers with C12))

Membrane filtration of these HMWSP leads to formation of a filter-cake and Membrane filtration of these HMWSP leads to formation of a filter cake and a rater complex gel-filtration process but filterability remains acceptable (channel opening mechanism)

Flow of these HMWSP in a core can lead to flowflow--induced gelationinduced gelation with significant retention of polymer within the gel with inin--depthdepth propagation of the gel

Permeability (i.e. porePermeability (i.e. pore--throat size, for granular media)throat size, for granular media), rather than hydrodynamics, appears as a critical parameter to trigger flow-induced gelation flow-induced gelation occurs only if permeability is low enough 5 µm < rp

C < 8 µm

Permeability threshold as well as gel strength will obviously strongly depends of Permeability threshold as well as gel strength will obviously strongly depends of HMWSP chemical compositionHMWSP chemical composition

5 µm < rp < 8 µm


Fine-tuning of HMWSP behavior in porous media is mandatory to ensure the success of mobility control and/or permeability reduction operations

Documents

33rd IEAEOR Syypmposiumiea-eor.ptrc.ca/2012/assets/s2/4 - Rousseau_Session 2_SLIDES.pdf · Introduction 4/5 Brief state of the art M bilit t lMobility control HMWSP considered as