CA1193473A - Well testing apparatus and method - Google Patents

Abstract

ABSTRACT

Well testing of either exploration or production wells is carried out by locating a hollow member, which contains teat instruments, in the well bore or within the internal bore of a drill string run, in such a manner that fluid flow up the bore is caused to take place along the path, at least a portion of which includes testing through the region within the hollow member where fluid is in direct communication with the test instruments and performing the well tests while permitting such flow through the member to occur or while preventing fluid escape from the member.

In the method of the invention well testing apparatus may be used for down-hole shut-in purposes even on production wells not provided with built-in shut-in facilities.

Description

~ell Testin~ Method Thi~ inventio~ rel~te0 ~o the tP~ting of oil or g86 explor~tion ~ells and ~o appar2~u6 for use in such tPsting.

In the evaluation of an oil or gas expioration well one of the principal par~s of tbe data scquisitioo i~ the drill stem te~t ~DST)~ Tbe DST is tbe producti~n of the reservoir flnid undPr carefully con~rolled conditions to provide ioformatio~ on the possible future performaD~e of a production well a~ tbe exploration site. In tbe DST, the columa of the drill pipe i8 u6ed as tbe temporary productioD
10 tubing~ .

DuriDg the drilling of ~ny well formation fluids are p~even~ed from enteri~g the well, under their own pressure by the weight of the column of drilling mud in the well. To en~le teæt productioa of fluid~ from a selec~ed formation through the drill pipe in a safe manner the nolumn o~ mud ~ust remain intact arouud tbe drill pipe.

An inflstable p~cker r~n, a~ part of tbe drill pipe column, provides sealing between the drill pipe ~nd tbe side wall of the well whicb may be bare rock or steel casing. To 20 enable production the drill pipe must contain a fluid wbich i8 botb of lower den~ity thaa tbe mud and gives bydrostatic bead pre~nre whicb i8 less than the formation pre6sure.

The mo~t use~ul data a~ailable from the DST are pressureq relating to the flowing well, and most importantly9 measurements of the build-up 4~ reservoir pressure when the well is closed in and the reæervoir is ~tablli~ng. The latter data gives the most direct lnformation on the permeability o~ the re~ervoir rock and the degree of damage to permeability in the immediate viclnity of ~he well~

In order to provide a basis for sound interpretakion the pre~sure measurement~ must be of great accuracy and the well must be able to be sbut~in down hole to prevent productlon o~ fluid~ into the well bore or settling out of fluid~ a.ter a surface shut inO The movement of fluids in the long vertical well bore after shut-in will cause a pressure transient that would obscure the reservoir effeots that ars of interest.

Hitherto conventional drill stem te~ting uses a-packer run which is placed in a point fairly near to the bottom of the drill string. A downhole shut-in valve is placed near to but above this. Clockwork driven recorders on Bourdon Tube type gauges are placed in protected holders below the shut-in valve to 'see' the reservoir ~lowing and shut-in pressures. A slmilar clockwork driven recording tbermometer provides te~perature data. ~his was the state of the art about four years ago.

9~
Thls system bad the f'ollowlng problemR:-a~ Inaccurate and in~ensiti~re gauges meant that long te~tswere required to provide data that could be interpreted with any reliabillty.

b) The engineer conductlng the te t had no knowledge of tha situation down hole or whether the gauges were even working.

c~ The gauges were run in the DST down hole equipment being ~ub jected to very rough handling during the run-in of drill pip~ -Wlth the advent of electrically operated pressure gauges theposs~ bility Or very much improved accuracy was off'ered.
However, there was one very major drawback the gauge had to be run on a conductor wlre-line and there~ore could not pass through the down hole shut-in valYe ~hich wsuld ob~iously 15 cut the wire. One alternative9 recently available,- i~ a~
electrical gauge with a self contalned recordin~ device.
This is designed such that it can be run in a conYentional ga ug e h ol d e r.

This system has the serious disadvantage of not 20 providing the engineer with information as the test proceeds requirlng the engineer to aot blindly not knowing exac~ly what is happening down hole.

On productioa well~ where down hole sb~t-ins are not normally po6~ible3 wire-line electricslly opera~ed gauges are ruo routinely~ Thi~ rPquire6 th~ careful moDitoring of af~ter flow well bore effec~s so ~hat tbis data can be igDor d ~d only reservoir effects con~idered. Thi~ ba~
major time disadvantsges in low produc~ivity gas wells aDd oil w'ells where a~ter flow effec~ are very prolonged and tests bsve to be e~tended~

Tbe mo~t recent develop~ent wbicb make~ electrical gauges a practical ~ool in DST's is the 'SPRO' ~ystem developed by Flopetrol/Dowell Schlumberger. Thi~ sy3tem uses a gauge built iot..o tbe down bole shut-in valve. Tbe gauge ;~ so arrallged as to give prPs0ure measuremants beaeatb ~be valve by providiag a pre~ure commu~ication to 15 ~be g~uge mounted sbove the ahut-ia device.

The gauge and ~but-ia assembly i8 run in ~6 part of tbe drill pipe colum~ and tbe ~ireline electri~sl Go~nectioo i6 made after the gBUge aDd valve ~ssembly i~ iD po~itio~.
Tbis bafi tbe following disadYa~tages:~

20 a) ~M elabora~e 6hu~:-in valve assembly run a~ part of tbe drill pip~ colum~ requiring tbe prese~ce at tb~ test ~f a speci~ t downbsle engineer. This togetber wieh tbe tool it~elf can prove very expe~sive..

~ ~ ~

b) Tbe gauge el~ctrical coa~ectioa bas to be made ia the preseace of ~el.l bore fluids and i~ not altogether reliabl~.

c~ The f 1QW tbrough ~be valve is restric~ed by 2 ra~her narrow path approximatPly 2.00cm dismeter.

The preseat inve~tioD propo8e-~ well te~ting appara~us wbicb seeks tv avoid the disadvan age~ associated with both wireline appasatu~ aMd ~pecially adapted pip2 ru~s aDd a method, employing ~uch apparatu~ for testiag wells~

According to the pre6ent inveatio~ tbere is provided lû a metbod for performing one or more designsted tests upon a well in wbich the well Eluid pressure i8 lesa tban tbe a6~00isted reversoir pressure so that well fluid can flow up tbe ~;ell towards the surface, the method comprisi~g locating a bollow member, containing ins'crulDents for ~easuring snd d~ta aquisition from said tests9 in the well bore il~ such a ~nanner thst the fluid flowi~g up tbe bore i~ cau~ed to take a p3'cb wtlich includ2s pas~age througb st least a por~io~ of tbe bollow memb~r in wbich ~sid fluid i6 i~l direct CQmm~OiCatiOn ~itb said islstrume~ts al~d performiDg said de6ignated te~t~ while p2rmittiDg ~ucb f low through ~aid ~em~er to ocur or while preventing f luid e~cape from the member .

Apparatus for u6e ia the method of tes~iDg of well~

,1 ~3~3 according to the pre~e~t invention may be in ~he form of an as~embly adapted ta be received withio the bore of a drill ~tr`ing and arra~ged to carry iastrumeats for dsta acquisi~ioa, ~he a6sembly compri~;ng a hollo~ ~ember provided witb longitudiaallg spaced iolet and ou~let port6 ~o allow pa~sage of fluid~ from the well upwQrdly tbrough the iolet ports iato the lower eod o tbe memker and a clDsure device wbicb is movable relative to the ~pper part o tbe member to clo~e the outlet port6, meaas for ac uating 10 tbe device to close the outlet port~ aDd mean~ for ~ealiog the aanalar 6pace betwe~a tbe lower ead of the me~ber and tbe wall of tbe pipe ru~ in the region betwee~ the inlet an outlet port6, ~sid iastrument~ being located witbin the member and being in dir.ect communication with fluid in tbe 15 region betweea tbe i~let --aad outlet portfi.

The ioveation will be described with reference to ~be acaompanyiag drawi~gs io wbich Figure 1 i8 a diagrammatic sectioaal elevation of oae form of tbe apparatus aDd Pigure 2 iB a diagrammatic sectio~sl elevatioa of anotber form of the appsratu~.

Referri~g to F;gure 1~ the assembly located witbiD tbe bore of a drill pipe 1 co~pri~ a bollow member 2 aad an iatern~l clo~ure device 3 which for~ a slidiog seal wi~bin ..
~j 3~3 tbe bollow member 2, The device 3 compriRes an uppermost cyliodrical plug body portion 4 lesdin~ to a lo~Prmost cyli-~d~ically hollow porti:on 5.

The bollow member 2 i8 provided ~ith longi~udin~lly spaced ports 6~7, ~hich ~ay be in tbe form of elongate slots iD tbe wall thereof~ The ls~ermo6t por~ 7 form ialees 8 for tbe well ~lnids wbile the uppermost ports 6 form ou~lets for the f lu;d.

Tbe bollow member 2 is closed a~ its lowermost end 8 10 and its provided tberein with in~trum~nt packages 9 or monitoriDg well fluid~. Tbe instr~ments may comprise pressure measuring devi~es3 tbermometers and flow meters.

Tbe closure devioe 3 is actuated by actuating meaos 10 . (shown schematically) iocluding a hydraulic/pneumatic~
15 hydraulic or electromscbanic~l driven ram 11 located ~itbin the bollow member 2 sbove the device 3 and secured tbereto.
Tbe drive device for tbe pisto~ may be remotely operated via a cable (not sbown) from tbe ~urface.

Cable6 (~ot ~bowD~ from the in~trument6 9 run to tbe sur~ace tbrougb 8 conduit (not sbo~n) ~hich is hermetic~lly sealed. Tbe conduit may be dispo6ed in a longitudinal recess in tbe i~er or outes wall o:E tbe member 2 os it ~ay e~tend upwardly tbrotlgb the ~ore of tbe member 2 through the closlJre device 3 and the ram 11 ia a manaer ~imilar to tbat sbown in Figl~re 2.

In use, the ram 11 iL6 aotualted to mol7e ttle clo~ure deyice 3 downwardly under tbe ac~io~ of a returu 6pri~3g 12 located above the device 3 a~d circ~mve~ing tbe ram 11.
5 Moveme~t of tbe device 3 dowo~ards causes tbe bollow portio~
5 thereof to co~er the outlet pOr~B 6 ~O seal of f tbe lower part of the bollow member 2. Tbe clo6ed position of tbe device 3 i8 showc in outlioe i~ Figure 1. Upon relea~e of tbe actuating mean~ tbe ram 11 i8 moved upwardly uader tbe 10 ac~ion of the return spring 12 to move the closure device 3 back to it8 original positio~ tbereby uncovering and reopening the outlet ports 70 :[n aDy case sbould 'che control si gaals to tbe actuatiug meaDs ~ail, tbe upward relesee of tbe clDsure device 3 occurs automatically~, In order to ~eal the annular æpace betwe~ tbe bollow membcr 2 and tbe wall of the pipe 1, an inflatable packer13 is provided i~ tbe regio~ between the ports 6 and 7~ - Tbe packer 13 may be inflalted bydraulically b~ remote co~trol from tbe ~urfaceu XO Tbe closure device 3 may comprise a form wbicb is a ~aria~t of tbat sbown il~ Pigure 1, For inst~nce tbe device 3 may merely comprise a ~ollow cyliDder~ ~lterna~ively it may comprise a bo110w cy1i~der whic~ ha.q a portion contai~ing port8 correspollding ~:o ~hose ou~let port~ 6 ia ~;

the bollow member 20 In this ~a~e9 the outlet ports 6 are opeo whel3 in oae loagi~udiaal po~ition they are aligoed with ~- the port~ i~ tbe cylinder whereaæ in aao~hPr longitudinal positioD displaced f~om tbe first3 tbe outlet ports S are clo~ed by ~n integr l w~ll portion of the cylindrical device~

~ s a furtb*r Yariant~ the device may compri6e a bollow cylinder ~itb circumfereatially spaced por~s wbich, in one po6ition, are alignable with the o~tlet port6 6 to opeo tbem. In anotber pOSitiOI3 to which tbe cylinder i~ moved by a limited an~ular rotation thereof the outlet ports 6 are closed by the wall of tbe cyiinderO In tbis ca~e of course tbe ~ctuatiag means m~3st be adapted to effect aa axial angular rotat;on of the oylinder rather than a longitudinally directed ~lidiDg movemeot thereof.

Referril3g to Figure 29 like parts bear tbe same reference aumerals a~ io Figure 1~ The closure device 14 compri ies ~n outer ~leeve ~bicb i8 Be~liDgly ~;lidable over tbe bollow member 2~ ~pward movement of the ~leeve 14 i8 20 limited by its engagemeot of a ~boulder 15 on the bollow member 2 formed bet;~een a lower por~ioll 16 a~d upper portioa 17 of greater dis3meter ~ban ~he lower por~io~O ~ sep~um 18 div$des tbe member 2 iuto ~pper and lower cbamber~ l9 and 20 respectiYel~, tbe lower chamber 20 inell3ding ~be por~ 6 and 25 7,.

~.

~3~3 ln Tbe sleeve 14 is co~Dected ~o ~be pis~on 21 of a xam 22 for moviDg tbe sleeve 14 slidably over ~be hollo~ inaer member 2. Tbe pistoD 21 bas ~adial ly directed porcio~s 23 e~te~ding tbrougb eloag~te longitudinal ~lots an tbe wall of ~he bollow member 2, wbich portion~ are cDnaected to the slePve 14 to permi~ movemellt thereof by tbe pi~on 21 moving xelative to tbe slot6. The ram 22 is actua~ed b~ f luid introduced u~der pressure in~o the upper part 24 of tbe chamber 19~ A f luid re~e:rvoir and f luid control valve~ (Doi:
~bown) are provided in tbe upper par~ 24 of the chsmber 19.

Exteodi~g from tbe ~urface tbrough tbe hollow member 2 by way of a central bore in the ram 22, piæton 21 and tbe septum 18 is a bermetically eesled conduit 25. T~e conduit 25 carries cablea (not æbown) for remote control of tbe 15 fluid reservoir and control valves aad o~ the in~trumeats 9.

~ ovement of the piatoD downward6 from the position sbow~ in F;gure 2 ~auses tbe fileeve 14 to move to cover tbe outlet ports 6 aad -upoa release of tbe ac uating fluid pressure io the ohamber 19, tbe ram 22, piæto~ 21 and æleeve 20 14 are urged upwardly u~der the actioa of the return ~pricg 12 which i~ mou~ted for compression be~wee~ tbe piston 21 ~d ~be ~eptu~ 18r Th e actuation nay be aGbieYed eitber hydx a u 1 i c I p o eu m a t ic al 1 y, b ydrau 1 i c a 1 ly or electromechanically.

Tile DST tool in accorda~ce wi~h ~he invention ~ay be rua into the ~ell bore by one o an alternative ~equence of operation6~ Firstly a conventional dow~ bole sbot in valve, in tbe shut modeJ may be r~n i~ as part of tbe drill string and, ~ub~eque~tly the DST tocl is lowered into the hole do~n the b~llow drill 6tem. ~pon openi~g of ~be lower dow~ bole sbut in vslve~ f low control i~ regulated by the valve ~6~embly of tbe tool. An alternative method of lociting the ~ool i5 to run in a drill string a~d ~o run iD 8D open ended drill 6tring down tbe bole. The column of mud in the drill stem is replaced ~ith a less dense fluid such as ~ea water, diesel oil or nitroge~ and tbence the DST tool i~ sunk tbrough the le~s dense fluid. After ~etting the tool the 15 fluid control is Bgain regulated by the valve asaembly of the tool.

The use of the testing tool in accordaace with tbe invention bas many tecbnical advantage~. An example is tbe selective perforation of interval~ between tests to evaluate 20 ~be performaace of sbor~ ineervals of tbe re~ervoir thiok~ess and t~eir- aggregateO Down-hole flowmet:er6 c:aD be run to mea~ure tbe flow from eacb group of perforations.

T~e present i~ve~tion ~ay be used ~itb advantage for te~'cing producirlg wells- Wbilst this may not be ~o 25 important or bigh rate oil an~ ga~ wells, in poor~r welli particularly witb tWo pbase flow, redistribution of tbe well bore contents ~fter sbut-in and af~er-fl~;~ iD~D a large capacity well can obscure valuable da~a, In order to provide this facility wi~cb eXisting equipmeat it ~a8 5 previously ~eces~ary to pro~lide a ~pecial nipple wbicb is an i~tegral part of the ~cubing string and must be run in wbeo tbe well is completed. Thus existiog wells ~bieh do not bave ~ modif ied tubing ætring CanDot be tes~ed witb the e~isting equipment. In contrast no modifications to the 10 production tubing are required ror use of the present inventioo and it may be used ou prZ-e~isting ~ells, Since in accordaoce with 1:be inve~t;on, tbe te~tiug in~ruments are QO~ usually run in wi h the drill string~
tbere i8 little risk of damage, as would be ia tbe case of 15 ~O~D ~ST tools siace they are sub ject to jarring ~s tbe dr;ll string is run in.

Further~ore ~iuce tbe messuring instrumeots are in direct commuDicatioD with the well fluids under te6t, anomolle~ such a~ temperature cba~ge~ a~d ~low pressure 20 cbange~ oa ~but-in are eliminated. Tâus results ~re availsble botb quickly aDd accurately, ~aving iu botb time and costs,

Claims (11)

1. A method for performing one or more designated tests upon a well in which the well fluid pressure is less than the associated reservoir pressure so that well fluid can flow up the well towards the surface, the method comprising locating a hollow member, containing instruments for measuring and data aquisition from said test, in the well bore in such a manner that the fluid flowing up the bore is caused to take a path which includes passage through at least a portion of the hollow member in which said fluid is in direct communication with said instruments and performing said designated tests while permitting such flow through said member to occur or while preventing fluid escape from the member.

2. A method as claimed in Claim 1 in which the well bore is a region defined by the internal bore of a pipe string run.

3. A method as claimed in Claim 1 or Claim 2 in which said hollow member is included in an assembly wherein said member is provided with longitudinally spaced inlet and outlet ports to allow passage of the well fluids upwardly through the inlet ports into the lower end of the member, and wherein said assembly further includes a closure device which is moveable relative to the upper part of the member to close the outlet ports, means for actuating the device to close the outlet ports and means for sealing the annular space between the lower end of the member and the wall of the well bore in the region between the inlet and outlet ports.

4. Apparatus for the testing of wells, in the form of an assembly adapted to be received within the bore of a drill string and arranged to carry instruments for data acquisition, the assembly comprising a hollow member provided with longitudinally spaced inlet and outlet ports to allow passage of fluids from the well upwardly through the inlet ports into the lower end of the member and a closure device which is movable relative to the upper part of the member to close the outlet ports, means for actuating the device to close the outlet ports and means for sealing the annular space between the lower end of the member and the wall of the pipe run in the region between the inlet and outlet ports, said instruments being located within the member and being in direct communication with fluid in the region between the inlet and outlet ports.

5. Apparatus as claimed in Claim 4 in which said sealing means is an inflatable packer.

6. Apparatus as claimed in Claim 4 or 5 in which the actuating means is pneumatically, hydraulic/pneumatically, hydraulically or electro-mechanically operated.

7. Apparatus as claimed in Claim 4 or 5 in which the closure device is received within the hollow member for movement within the member to close the outlet ports.

8. Apparatus as claimed in Claim 4 or 5 in which the closure device is received within the hollow member for movement within the member to close the outlet ports, and in which the closure device is longitudinally/slidable within the hollow member and the actuating means is adapted to cause the device to slide longitudinally.

9. Apparatus as claimed in Claim 4 or 5 in which the closure device comprises a sleeve for the hollow member, the sleeve being longitudinally slidable over the upper part of the hollow member to close the outlet ports and the actuating means being adapted to cause the sleeve to slide longitudinally.

10. Apparatus as claimed in Claim 4 or 5 in which the actuating means is pneumatically, hydraulic/pneumatically, hydraulically or electro-mechanically operated, and in which the closure device is longitudinally/slidable within the hollow member and the actuating means is adapted to cause the device to slide longitudinally.

11. Oil and gas well incorporating the equipment as claimed in Claim 4.