260810 lessons from montara and bp blowouts.ppt

8/11/2019 260810 Lessons from Montara and BP blowouts.ppt

1/17

O I L S E A R C H L I M I T E D

Barriers to flow

Surface or seabed

Shallow casings set to prevent

hole collapse or losses of mud

Sandstone containing oil

and gas

Cement to seal around casing,

prevent leak to surface

Pressure from heavy mud prevents

gas / oil flowing into well

Wellhead and BOP allow closing in at

surface or seabed if flow occurs


2/17


Lessons from Montara and BP

blowouts update onimplications to OSL

L Bundesen / C Fraser26thAugust 2010


3/17


Before blowout caught fire


4/17


Montara well diagram suspension

Sea level

Seabed

ormation

top

!his bo" indicates #mud line hanger$

Casing #shoe track$

%& &/'$ casing cemented in %( )$ hole

* +/'$ casing in % -$ hole

Blowout preventers removed during suspension and casings removed to seabed

Pressure.containing corrosion cap on * +/'$

Brine left in * +/'$

B00120S 0234156 O57%8 Cemented * +/' inch

8 Brine left in * +/' inch

&8 Pressure containing corrosion cap


5/17


Causes of Montara Blowout

Inquiry results not yet released, however

ver!dis"la#ed a$ter % &/'( #e)ent *o+, leaving "ath $or oiland /or gas to $low u" the inside o$ the #asing

id not #ondu#t "ressure test o$ the #e)ent *o+ a$ter that

Inadequate +arriers in "la#e -+rine that )ay have +een toolow a density. sealing #orrosion #a" and re)oved the#orrosion #a" without having Bs installed

A$ter a "eriod o$ hours, the well #o))en#ed $lowing

u)an errors, la#3 o$ review, #utting #orners


6/17


Causes of BP Blowout:Inquiries and ata Sources

Full in$or)ation is not yet availa+le. in$or)ation here is

+ased on a nu)+er o$ sour#es, )ainly B and 4ranso#eandra$t investigations availa+le on internet. 5 enate su+!#o))ittee inquiry letter to B and 780 day( re"ort +y the5A e"t o$ Interior to the 5A resident

In$o on ne9t slides is +ased on a B dra$t do#u)ent. theyshow an overview o$ what the #riti#al $a#tors were

4he in#ident o##urred during dis"la#e)ent o$ )ud +yseawater "rior to setting the $inal -shallow #e)ent "lug+e$ore dis#onne#ting the B and riser and leaving thelo#ation -with intention o$ #o)ing +a#3 later to #o)"letethe well as an oil "rodu#er


7/17O I L S E A R C H L I M I T E D

Causes of BP Blowout:O!er!iew of Critical "actors

Criti#al Fa#tors

1 Loss o$ Integrity o$ the % :/'( 9 :( #asing#reated a "ath $or hydro#ar+on -C in$lu9

2 5nre#ogni;ed well #onditions

< In$lu9 unre#ogni;ed ! Integrity test $ailedto identi$y #o))uni#ation with thereservoir

< "erations allowed C in$lu9 to enter and)ove u" the well +ore < well becamecapable of flowing

< =es"onse $ailed to #ontrol the well

8 B > ?)ergen#y yste)s $ailed to isolate theC sour#e

@ as "lu)e ignited

upper annularlower annular

LMRP connector

Riser

blind shearcase shear

Top of Wellhead mudline 5,067

T!"#,$60

BOP

%ariable pipe ram

7/8 x 7 Casing

Wellbore fuid

Seal Assembly

Floa Collar

Cemen

!rillsring



Critical "actor # Loss of Integrit$ ofCasing

Loss of Integrit$ of %&'()* + '* Casing

< Ce)ent $ailed to isolate thereservoir

< 4he $loat #ollar -1 or the sealasse)+ly -2 lea3ed



BP Blowout Causes: Casing Cementing

Losses during drilling hole, oil / gas +earing

Internal B ris3 review #onsidered the o"tion o$ running and#e)enting a liner, thus allowing an additional dee" set +arrier -linerto" "a#3er, then tying +a#3 with #asing to sea+ed B re*e#ting thato"tion and #hose instead to run a $ull string o$ -ta"ered #asing +a#3to the sea+ed It is alleged that this de#ision was solely to #ut #ost

B used a $oa) #e)ent to )ini)ise losses. 4ranso#ean alleges itwould ta3e @' hours to develo" reasona+le strength

Alleged not enough #e)ent "u)"ed, % atte)"ts to a#tivate the $loatvalves, other #e)enting issues

Casing was not as well #entralised as re#o))ended +y alli+urton

verall, the #e)ent *o+ design had an in#reased ris3 o$ hydro#ar+onin$lu9 during #e)ent setting



,ellhead rawing Showing Seal-ssembl$ and Loc.down



BP Blowout Seal -ssembl$

4he other "otential lea3 "ath identi$ied +y B is u" the annulus and"ast the 7seal asse)+ly(

B says 7et and test o$ seal asse)+ly was nor)al(

4he letter $ro) the enate u+!Co))ittee to B alleges 7$ailure tose#ure the wellhead with a lo#3down sleeve( Also alleged +y4ranso#ean who also question whether 7outer lo#3 ring( was run onthe #asing hanger

4ranso#ean allege the "ressure was su$$i#ient to 7$loat( the #asing -li$thanger and seal asse)+ly o$$ nor)al "osition u""osition is that theseal asse)+ly and/or #asing hanger )oved u" and wedged a#ross theBs, "reventing the) $ro) e$$e#tively #losing to seal o$$ the well

4ranso#ean #o))ent that all B tests were done / "assed



Critical "actor /:0nrecognised ,ell Conditions

Integrity test $ailed to identi$y #o))uni#ation with thereservoir (plug bumped, casing pressure test to

2500psi was reported to be successful)

"erations allowed C in$lu9 to enter and )ove u" the

well +ore < well became capable of flowing

(see later comments about the operation of displacingmud with seawater)

=ig #rew res"onse to well $low $ailed to #ontrol the well



isplacement of Mud b$ Seawater1# of /2

B internal do#s say the #asing was su##ess$ully "ressure tested to2&00"si

e9t ste" was trans$erring )ud to a +oat while dis"la#ing the )udwith seawater -in "re"aration $or setting shallow #e)ent "lug thendis#onne#ting the B and riser

B ad)its that the )ethod o$ trans$erring )ud did not allow)onitoring $or 3i#3s

4hey also ad)it that the o"eration was #on$using as regards the"ressure over+alan#e or under+alan#e #reated in the well 4here

were une9"lained "ressures during the o"eration

At one "oint the #rew +led o$$ "ressure, +ut )ay have ta3en a 3i#3-B inter"retation



isplacement of Mud b$ Seawater1/ of /2

4hey )onitored "ressures at the #e)ent unit. Ce)enter saidthe well #ontinued to $low and s"urted. shut 3ill line and"ressure +uilt

A$ter )onitoring, #rew were satis$ied the well was dead -+ut Blater inter"retation was that an in$lu9 was in #asing or annulus

4hey o"ened the annular B and #ontinued with dis"la#e)ento$ the well to seawater, #he#3ed that there was no oil sheen,then "u)"ed over+oard -$ro) that "oint, they had no )easureo$ $low out

Later #he#3s o$ the dis"la#e)ent rates and return $low ratesshow that the well was $lowing -B in$o, +ut this was notdete#ted at the ti)e



Critical "actor 3 BOP failed to seal

A#tion to a#tivate the B on#e well #ondition was

re#ogni;ed, $ailed to isolate the sour#e

?)ergen#y is#onne#t yste) $ailed to se#ure the well-when a#tivated $ro) +ridge a$ter e9"losion 4he ?$un#tion #an +e a#tivated $ro) either the +ridge or drill$loor Its $un#tion is to seal the well and dis#onne#t thevessel $ro) the well

ADF/ead!)an $ailed to se#ure well 4he ADF is ane)ergen#y sequen#e that should a#tivate the +lind shearra)s to seal the well

u+sequent =E interventions $ailed to se#ure the well



Lessons for Oil Search fromMontara and BP blowouts

ro+le)s during #e)enting a##ount $or &0 o$ +lowouts -in$ogiven to Dontara Inquiry

< i))ediate #ause o$ Dontara +lowout and )ost li3ely root #ause onthe B one

rogra)s with )ini)al and un#onventional +arriers< us"ension o$ Dontara well would not have satis$ied L +arrier "oli#y

$or two inde"endently tested )e#hani#al +arriers

eries o$ #hanges o$ "lan -short#uts without ris3 assess)ent

Changes to +arriers and "rogra)s -without "ro"er ris3assess)ent, "ro#edures, #ontingen#y "lans and understanding o$"ersonnel on site

< =eview and #ontrol $ro) the o$$i#e is #riti#al Dorning o"s )eetingsand regular "eer reviews are standard "ra#ti#e in L

-Dontara La#3 o$ understanding o$ site "ersonnel that they had a#e)enting "ro+le). no thorough #he#3 o$ re"orts +y line)anage)ent or "eer review

-B La#3 o$ #are or understanding o$ site "ersonnel duringdis"la#e)ent o$ )ud < did not realise they had well 3i#3ing then$lowing



Oil Search Blowout Pre!ention in place

4horough drilling design and "rogra))ing with "eer review andline )anage)ent #he#3

< eer and )anage)ent reviews and sign o$$ at )anage)ent level

u""orted +y very detailed "rogra)s $or ea#h se#tion o$ well.these are read through with rilling u"ervisor and servi#e#o)"anies

< re!"hase )eetings to "revent a)+iguity/)isunderstandings

tri#t )anage)ent o$ #hange "rin#i"les well understood and"ra#ti#ed

< eer review and ris3 assess)ent o$ any signi$i#ant o"erational #hange

?nsure rilling ?ngineering 3ee"s u" with 7what is ha""eningdown holeG( It is too late to analyse it a$ter the in#ident

4o" quality rilling u"ervisors at rigsite< L "ay a "re)iu) $or highly e9"erien#ed wellsite su"ervisors

?qui")ent "ro"erly designed, )aintained, tested every ti)e

trong #ulture throughout the organisation that sa$ety is not#o)"ro)ised $or 7"rodu#tion(

260810 lessons from montara and bp blowouts.ppt

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