Skin Effect and Formation Damage

Well Stimulation and Sand Production Management (PGE 489 )

Skin Effect and Formation Damage By Dr. Mohammed A. Khamis 02-02-2016

Skin Factor  •

  A formation damage damage model is a dynami dynamicc relatio relationship nship expres expressing sing the fl flui uid d tran transp spor ortt ca capa pabi bili lity ty of po poro rous us me medi dium um un unde derg rgoi oing ng va vari riou ouss alteration processes.

•

  Mode Modeli ling ng form format atio ion n dama damage ge in pe petr trol oleu eum m re rese serv rvoi oirs rs has has be been en of  cont co ntin inui uing ng inte intere rest st.. Alth Althou ough gh many many mo mode dels ls ha have ve be been en pr propo opose sed, d, these models do not have the general applicability.

Hawkins’ Formula

   pideal   p s   p  real 

Hawkins’ Formula   r  s   ln    preal    p s   pwf    ,real   2 k  s h  r w   q 

  r  s   ideal   s wf  ,ideal   p   p   p    2 kh ln    r w   q 

 p s 

q  2 kh

 s

pwf  Ps

Steady-state pressure drop due to skin is given by:

 p s   p  real     pideal  r w

  r  s   q    r  s       s  ln  ln    2 kh 2 k  s h  r w     2 kh  r w   q 

1

k 

 s

q 



 r  s    1 ln    r  s   ln   k  s  r w    k   r w   1

 s

 r    s    k    1  ln       k  s     r w  

r s

Hawkins’

Formula

Hawkins’ Formula  preal  

dr 



2 h r w rk (r )

 pideal      p s 

r  s

q 

  r  s     2 kh  r w   q 

q 

2 kh

ln 

 s pwf 

Steady-state pressure drop due to skin is given by:

Ps

 p s   p  real     pideal 

q  2 kh

 

 s 

dr 

q 



ln 

w

r  s

  r        s  l n  k  rk ( r )   k  r  1

r w

  r  s     2 h  r  rk (r )  2 kh  r w   q 

r s

r s

dr 

1

 s

r  s

  r     ln   s   s  k  rk (r )  r  dr 

General Hawkins’ Formula

r w

    w

r w

  w  