Mileva  Radonjic  Tevfik  Yalcinkaya,  Nnamdi  Agbasimalo,  Abiola  Olabode,  

Tao  Tao  and  Dinara  Dussenova  

             

   

         

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Cra*  &  Hawkins  Department    

of    Petroleum    Engineering  

Louisiana State University

Tel: +1-225-578-6042; fax: +1-225-578-6039 E-mail address: mileva@lsu.edu

The  Effect  of  CO2-­‐Saturated  Brine  on  the  ConducHvity  of  Wellbore-­‐Cement  

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Source:  Carbon  Capture  Project,  www.co2captureproject.org/about_storage.html  

Depleted  Oil  and  Gas  Reservoirs   Deep  Saline  Aquifers  

+•  Many  abandoned  wells  give  access  to  the  reservoir  •  Subsurface  geology  is  known  •  ExisHng  infrastructure  reduce  cost  

•  High   s to rage   Capac i ty  (*3,634-­‐13,909   billion   tons  for  North  America)  

-­‐  •  Limited   Capacity   (*152   billion   tons   for   North  America)  

•  Abandoned   wells   top   risks   for   the   CCS   projects  because  of  a  possible  leakage  

•  Subsurface   geology   is   not  thoroughly  known-­‐risks  

US  Departm

ent  of  Energy,  www.doe.gov  

CCS:  Capacity,  Types  of  Storage    

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Containment  –  Trapping  -­‐  Risk    hSps://w

ww.crc.gov.au/Inform

aHon/default.aspx)  

1.   99%  of  injected  CO2  must  remain  trapped  for  this  technology  to  be  effecHve  over  a  minimum  500yrs  period.  

2.    In  the  injecHon  period,  trapping  is  only  provided  by  physical  barrier  systems  such  as  CAP-­‐ROCK  and  WELLBORE  CEMENT.  

•  More  than  8,000  wells  in  the  GOM  have  sustained  casing  pressure.  (U.S.  Federal  Register,  2010)  

•  14,477  wells  out  of  the  316,439  wells  in  Alberta,  Canada  are  leaking.  (Watson  &  Bachu,  2009)  

•  CO2  sequestraHon  cannot  be  carried  out  in  the  presence  of  leaky  wells.  

Motivation

MoHvaHon  

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Primary  ObjecHve    

•  To   invesHgate  the  change   in  the  fracture  aperture  when  exposed  to   CO2   saturated   brine.   Fracture   aperture   will   affect   the   overall  hydraulic  conducHvity  of  wellbore  materials.  

 Secondary  ObjecHve    

•  To  evaluate  porosity  alteraHons  in  cement  when  exposed  to  acidic  brine   using   material   characterizaHon   techniques.   Porosity   of  cement  is  important  since  it  is  related  with  permeability  (strongly  Hed   with   zonal   isolaHon)   and   strength   of   cement   (mechanical  integrity).  

ExisHng  imperfecHons  in  cement  sheath  can  endanger  safe  and  long-­‐term  containment  of  CO2  in  the  subsurface.  

         •  Total  failure  of  the  sequestraHon  project  

•  ContaminaHon  of  Underground  Source  of  Drinking  Water  (USDW)  

•  AcidificaHon  of  soils  with  adverse  effects  on  vegetaHon  

•  Geo-­‐mechanical  disrupHons  of  the  subsurface    

Consequences of failure of wellbores