SPE Distinguished Lecturer Program The SPE Distinguished Lecturer Program is funded principally through a grant from the SPE Foundation. The society gratefully acknowledges the companies that support this program by allowing their professionals to participate as lecturers. Special thanks to the American Institute of Mining, Metallurgical, and Petroleum Engineers (AIME) for its contribution to the program. Society of Petroleum Engineers Distinguished Lecturer Program www.spe.org/dl
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SPE Distinguished Lecturer Program
The SPE Distinguished Lecturer Program is funded principally through a grant from the SPE Foundation.
The society gratefully acknowledges the companies that support this program by allowing their professionals to participate as lecturers.
Special thanks to the American Institute of Mining, Metallurgical, and Petroleum Engineers (AIME) for its contribution to the program.
Society of Petroleum Engineers Distinguished Lecturer Programwww.spe.org/dl
Injectivity Impairment and Well & Water Management
Prof. Pavel Bedrikovetsky
Australian School of Petroleum, U of Adelaide
PETROBRAS, Brazil
Society of Petroleum Engineers Distinguished Lecturer Programwww.spe.org/dl
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ContentsIntroduction1. Formulation of the problem
2. Deep bed filtration & External filter cake formation
3. Erosion of external cake
4. Early effect of varying oil-water mobility ratio
5. Damage characterisation and prediction
6. Taking advantage of formation damage: IORConclusions
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Injectivity index II = q/Δp decreased 10 times during 15-year waterflooding in giant offshore field
(Campos Basin, Brazil)
INJECTIVITY INDEX vs TOTAL WATER INJECTED
0102030405060708090
100
0 500 1000 1500 2000 2500 3000Wi
II fin
al / I
I inic
ial
(%)
POÇO A POÇO B POÇO CPOÇO D POÇO E POÇO FPOÇO G POÇO H PÇO H_ PD GPo t ência ( PÇO H_ PD G)
1. Formulation of the problem
103 m3 water injected
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Different physics mechanisms of retention
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OIL RESERVOIR
NON-PRODUTION FORMATION
OIL (+WATER)
SURFACE TREATMENT
FRACTURE INJECTION
LOSS OF INJECTIVITY
SUB-SEA RAW WATER INJECTION
DOWNHOLE OIL-WATER
SEPARATION
SUB-SEA OIL-WATER SEPARATION
UNDERGROUND DISPOSAL
DUMP FLOODING
ON-LINE MONITORING
LOW BSW: DIRECTLY TO TERMINALS
PRODUCED WATER
REINJECTION
DISPOSAL IN SEA
Water management cycle
AQUIFER OILY PARTICLE CONCENTRATION
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What can you do about injectivity decline
• Water filtering: filter choice?
• Chemical treatment: what type of chemical?
• Acidizing: when? acid volume?
• Fracturing: when?
• Add perforation holes: when? size?
Decisions !!!
Decisions !!!
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2. Deep bed filtration and external cake formation
Particles filtrate deep into formation, fill in the inlet, stop filtration and form external filter cake
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Filtration coefficient λ
λ- particle capture probability per unit of its path; c - suspended concentrations; σ - retained concentrations; U - velocity
cσ
( ,U )Uctσ λ σ∂
=∂
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Darcy’s law accounting for permeability
damage
( )∇0kU = - p
μ 1+ βσ
1
0 σ
k( )σk0
Formation damage coefficient β
U – velocity, σ - retained concentrations; k - permeability; μ - viscosity; p - pressure
due to increasing leakage of untreated water and increasing formation damage; increase of areal
sweep
6. IOR & Waterflood management by fracture propagation
Unfavourable stress environment: low sweep
Favourable stress environment: high sweep
Perforation density along the column :
N(x) = ?
Non-uniformal perforation homogenizes injectivity profile and increases sweep efficiency
Injectivity damage also homogenizes injectivity profile and increases sweep for any “unpredictable” heterogeneity
P. Dore, P. Bedrikovetsky et al., 2005, SPE 99343
Injector Producer Sweep increase due to formation damage and non-uniform perforation
Sweep improvement due to precipitation/sorption
High Permeability Zone
Injector Producer
Water sweep front without skin
Water sweep front with skin
Induced skin Low
Permeability Zone
Polymer flooding –adsorption of polymer CO2 flooding – precipitation of asphaltenesCold waterflood of waxy oil - precipitation of paraffins
Idea of oil recovery increase by injection of water with particles: The damage is high where the injection rate is high, i.e. the injectivity profile becomes more uniform and sweep efficiency increases
Khambharatana, Faruq Ali et al. (1998) – poor sweep increase with vertical injectorsSoo, Radke, (1999) – less SorPresent work (2009) – the same effect with horizontal wells
High Permeability Zone
Injector Producer
Water sweep front without skin
Water sweep front with skin
Induced skin
Minor effect of sweep increase at the very beginning of water injection
Water Oil
With skin (0.1 p.v.i) Without skin (0.1 p.v.i)
Small saturation difference can be observed near to injector in low permeable zone
Water Oil
Skin results in high increase of the final sweep from low permeability zone
With skin (2.0 p.v.i) Without skin (2.0 p.v.i)
P. Bedrikovetsky et al., 2009, SPE 122843
Implementation of damage option S(tD) into waterflood simulators (IMEX, Eclipse)
An accurate prediction of injectivity allows to plan well stimulation - fracturing, acidification, etc.
Applications
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Filtration coefficient determines the size of the damaged zone
-prediction of required perforation length to bypass the damage-calculation of required acid volume to remove damage
'1λ
σ += wd rr
P. Bedrikovetsky et al., 2009, SPE 122844
Highly successful case – field M-A (Equador)
2acid dV r hπ φ=
Database of injectivity damage parameters from lab tests and well history
Prediction of injector behaviour for “new” fields, not yet submitted to waterflooding, based on basic data on permeability, porosity, pore size distribution
The developed theory can be applied for •drilling-fluid-invasion-induced formation damage, •fines migration and damage of producers, •gravel pack impairment, •sand screen design
Applications
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Theory for well injectivity impairment shows
•Good match with field data
•Good match with laboratory tests
3-point-pressure tool characterises injectivity damage system and is used in field / platform conditions
Mathematical model is implemented in software SPIN
Database of damage parameters –> for injectivity prediction
Conclusions
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Collaborators:
•A L Serra de Souza, C A Furtado, P Dore, A G Siqueira, F Shecaira(Petrobras, Cenpes)
•R Paiva, A Santos, M da Silva, Maylton F da Silva, A C Gomes, E Resende
(UENF-Lenep / Petrobras)
•F Al-Abduwani, P Currie, W. Van den Broek,(Delft University of Technology, The Netherlands)