D IS C U S S IO N .
Mr. Ha r r is (C h airm an ) : I n o p e n in g th o p a p e r for d iscussion, I ta k e th o o p p o rtu n ity o f c o n g ra tu la tin g th e a u th o r o n th e v e ry lu cid w ay in w h ic h h e h a s p u t th o p ro b lem s b efo re u s. I a m p ro p o sin g t h a t c o m m e n ts o n th e p a p e r sh o u ld b o re p lied to b y th e n u th o r d ire c tly a f te r th o c o m m e n ts h a v e b een m ad o b y each sp e a k e r.
Mr. Wa llin g : I sh o u ld like, firs t o f all, to c o n g ra tu la te th o a u th o r o n h is v e ry in te re s tin g p a p e r. I w o u ld like to kn o w w h a t ex p erien ce th o a u th o r h a s h a d in
“ p a r a c h u ti n g ” p lu n g e rs— t h a t is, in re d u cin g th e fallin g v e lo c ity b y m e a n s o f a n orifice in th o co n tro o f th o p lu n g e r. W h e n m y c o m p a n y firs t s ta r te d p lu n g e r lift, m a n y w ells tu r n e d u p in w h ic h th o p lu n g e r h i t b o tto m h a r d , d u e to to o little fluid. O n th e a d v ice o f th e m a n u fa c tu re rs o f th e e q u ip m e n t, w e in tro d u c e d th e sy s te m o f p lac in g a n orifico in th o p lu n g er, a n d fo u n d t h a t fallin g v e lo c ity co u ld bo c o n tro lled b y th e size o f th o orifice. T h is c o m p le te ly re v e rse d o u r id eas a b o u t th o sy s te m . I n a w ell 1800 fe et deep , p ro d u c in g a t th o r a te o f 2 b r l./d a y , w ith th o p lu n g e r m a k in g th re e to fo u r s tro k e s a n h o u r, th e o v erall c o st w a s e q u a l to 17 c. p e r brl. W e w e re n o t in te re s te d in th o sh a p e o f th e p re ssu re c u rv es w e o b ta in e d , p ro v id e d th e w ell o p e ra te d w ith o u t d a m a g e to e q u ip m e n t.
W ith re g a rd to p lu n g e r lift, I w o u ld lik e to k n o w w h a t th o a u th o r co n sid ers a s a fa ilu re. W a s h is s ta te m e n t b a s e d o n th e s tu d y o f c h a r ts , o r w as i t a co m p leto failu re t h a t co u ld n o t b e o p e ra te d b y a n y m a im e r o f m o an s ?
T h e re is no d o u b t t h a t th o in tro d u c tio n o f p a ra c h u tin g m a d e a b ig difference, a s fa r a s o u r ex p erien ce goes in defin in g th e lim it to w h ic h w e c a n go. W e h a v e t h i r t y w ells p ro d u c in g a n a v era g e y ield o f 10 b r l./d a y e ac h a t a n econom ic c o st. I sh o u ld like to k n o w th o c o st o f p ro d u c tio n a s fa r as th e a u th o r ’s e x p erien ce goes. I t is a f u n d a m e n ta l p o in t a s to th o valu o o f th e sy s te m in p ro d u c in g oil.
Mr. We l l in g s : I a m a fra id m y ex p erien ce as fa r a s p a r a c h u tin g goes is r a th e r lim ite d , a s in th is field wo seldom co m e a cro ss w ells t h a t re q u ire it. I n o n e w ell w h ere i t w as tr ie d th e re s u lts w ere n o t e n co u rag in g , a s th e d e creased v e lo c ity te n d e d to cause th e p lu n g e r t o s tic k . I n a n o th e r caso o f a low -fluid-lovel w ell, b lee d in g g as fro m th o c asin g o v ercam e th e d ifficu lty o f th o p lu n g e r h ittin g b o tto m h a rd . A s m e n tio n e d in th o p a p e r, th e c o n sisten cy o f th e fluid a t th o b o tto m o f th e tu b in g is o f first im p o rta n ce , a n d a s re m o v a l o f g as fro m th o c asin g c an affect th is , i t w o u ld seem t h a t u se o f s ta n d a r d ty p e p lu n g e rs co u ld bo e x te n d e d to m a n y w ells o f low fluid level m ere ly b y b leed in g off gas. I t a p p a re n t ly re q u ire s v e ry little flu id o f th e c o n siste n c y o f d e a d oil to slow d o w n th e p lu n g e r a b o v e th e foot-piece.
A s to w h a t I c all a failu re, in th is field w o c o n sid er a p lu n g e r-lift w ell a success so lo n g a s i t d o es n o t re q u ire to o fro q u en t a tte n tio n o r to o m a n y re p la c e m e n ts. I n so m e sa n d y w ells th e p lu n g e r w ill seldom m a k e tw o successive s tro k e s w ith o u t stic k in g u p ,
WELLINGS : SOME NOTES ON PLUNGER LIFT OPERATION.— DISCUSSION. 2 7
2 8 WELLINGS : SOME NOTES ON PLUNGER LIFT OPERATION.— DISCUSSION.
O n p a g e 25 tw o cases a re q u o te d w h ere p lu n g ers c o n tin u e d to o p o ra to ev en w h e n th o rin g s h a d boon w o rn off c o m p letely . W o u ld n o t th o w olls h av o gone on p ro d u c in g if th e p lu n g ers h a d b e o n ta k e n o u t a lto g e th e r ?
M r . We l l i n g s : P lu n g e r lift is in tro d u c e d n e a r th o e n d o f a w ell’s flow ing d a y s to increaso th o efficiency o f p ro d u c tio n . A s p re v io u s ly m en tio n ed , th e re is u s u a lly q u ite a largo in crease in p ro d u c tio n w h e n su c h a w ell is p u t o n p lu n g o r lift.
I n th o cases q u o te d ivhoro p lu n g ers c o n tin u e d to o p e ra te in a v e ry w o rn co n d itio n , n e ith e r w ell w o u ld flow u n a ssiste d , a n d o n ly g av e a sm all p ro d u c tio n w h en s tr a ig h t liftin g . I t seem s t h a t th o tu rb u le n c e c a u sed b y th o p lu n g e r’s rin g s is c a p a b le o f m a in ta in in g a seal o f co n sid erab le cro ss-sectio n al a rea.
Mr. Wa l l i n g : I w o u ld like to k n o w w h e th e r th o a u th o r h a s s tu d ie d th e q u e stio n o f ru n n in g p lu n g o r lift tu b in g o n th o co m p le tio n o f w ells, th u s av o id in g th e n e ce ssity o f h a v in g to p u ll th e orig in al flow strin g .
Mr. We l l i n g s : T ho q u e stio n h a s b e e n s tu d ie d . C o st is u s u a lly th e d ecid in g fa c to r. Sinco p lu n g e r l if t tu b in g is c o n sid era b ly m o re o x p en siv e t h a n o rd in a ry tu b in g , it is n o t econom ic to tio i t u p in a w ell t h a t is likely to flow fo r a n y le n g th o f tim e . F u rth e rm o re , u n less th o tu b in g h a p p e n s to bo s e t a t th e c o rre c t d o p th a t th o s t a r t, th o serv ices o f a p u llin g crow aro ro q u ired an y w ay .
M r. Pa t e r s o n: O n p ag o 19, th o a u th o r s t a t e s : “ I n g en eral, wolls sho w in g s te a d y c asin g a n d tu b in g p ro ssu rcs . . . will o p e ra te su ccessfu lly o n p lu n g e r lift, p ro v id ed th e y a ro re aso n a b ly freo fro m sa n d a n d -w ater.” I w ould like to k n o w so m e th in g a b o u t th is , a s I h a v e a case o f a woll p ro d u c in g 04 b rl. o f oil a n d 240 b rl. o f w a to r p e r d a y .
Mr. W e l l i n g s: M y oxperionco h a s te n d e d to show- t h a t wolls p ro d u c in g a n y th in g abovo a b o u t 5 p e r c e n t, o f w a to r a re likely to givo tro u b lo so o n er o r la te r, esp ecially in th o case o f low fluid levels. T h is n e e d n o t a p p ly if th o p ro p o rtio n o f oil a n d w a te r flow ing in to th o holo re m a in s c o n s ta n t. I f th o p ro p o rtio n v aries, s h o r t s tro k in g w ill re s u lt, b u t, a s a lre a d y s ta te d , th is n e e d n o t cau se tro u b le in a woll w ith a h ig h fluid level.
2 9