Dst Concept

7/21/2019 Dst Concept

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DST CONCEPT


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DST Concept

Lecture Objectives.By the end of this lecture , YOU should beable to

!ist the " #ain DST co#ponents

!ist the " #ain DST pressures

!ist the " #ain DST types Describe the DST concept


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The pri#ary DSTfunctions, $hetherconducted in openhole

or cased $ells, are to

%solate the tar&et'one( Control $ell )o$( Con*ey )uid tosurface( +cuire do$nholedata(

DST Concept


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DST Concept

The 3 basic euip#ent fora drill ste# test consits of astrin&-tubin& or drillpipe., apac/erand a *al*e(

1. The stringchannels the )o$ tosurface(

2. The packeris arubber ele#ent toisolate the 'one to

be tested(3. The valvepro*ides

a #ethod ofcontrollin& the $ellnear the reser*oir(


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Ph: 0ydrostaticpressurePf: 1or#ationpressurePc: Cushion pressure

2enerally, therelationship a#on&

these pressures is

Ph > Pf > Pc

DST Concept

3


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The Packer isolates the for#ationfro# the annulus, the t$o pressures-Ph and Pf. #ust be isolated fro# oneanother(

The Tester valvecontrols thefor#ation(3 shut the $ell do$nhole to #ini#i'e$ellbore stora&e e4ect3 isolates annular )uid fro# cushion$hile 5%0, pre*entin& U3tubin&

3pro*ides a seal for pressure test thestrin&

+fter the pac/er is set and sealed, thetest *al*e can then be opened and

hydrocarbons can be produced tosurface(

DST Concept


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6( 78! perforated 9o*er3balance:

;( 5%0 DST $ith Tester *al*eclosed,


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6( Open the re*erse circulatin&*al*e and 95e*erse out: -)ushhydrocarbons fro# drillpipe ortubin&.(

;( Close the re*erse circulatin&*al*e(

"( Open the tester *al*e(

=( Pu#p #ud into test strin& to /illthe tested inter*al(

?( Unseat the pac/er(

@( Pull the strin& out of the holePOO0

DST Concept

The &eneral steps for endin& aDST are


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DST Concept

Tpes of "#T


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DST Concept

$ell location % con&guration

DST C t 8


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DST Concept 8P+CAE5S

P+CAE5S are desi&ned to isolate theperforated inter*al fro# the #udcolu#n( The $ei&ht applied on thepac/er co#press its rubber ele#entsa&ainst the casin& and creates a sealbet$een the annulus and tubin&(

Three #ain types of Pac/ers

3 'le(Pac packer

3 PosiTest packer

3 Positrieve packer


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DST Concept 8P+CAE5S

1lePac

PosiTest Positrie*e


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DST Concept 8 Testeral*es

)arious tpes are use*:

+ ,'- ,ulti 'low -valuator/

Operated by #anipulation of the test strin&(

+pplications Onshore and ac/3up ri&s

3 P0T Pressure 0ontrolle* Tester/

Operated by annulus -and tubin&. pressure(

+pplication O4shore, )oatin& facilities(

3 # *ual+valve tool ")/

-%5%S %ntelli&ent 5e#ote %#ple#entationSyste#.

Operated F +pplication as PCT


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DST Concept 8 Testeral*e

%5%S dual3*al*etool

PCT*al*e

T bi d ill i


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Tubin& or drillpipe

Slip Goints -; or #ore.

Drill collars

5edundant circulatin&*al*e

Drill collars

Surface 5ead out

5+ #ar/er

Drills collar

Surface readout

Do$nhole *al*e

0ydrostatic reference tool

Pressure recorders -; or#ore.

0ydraulic Gar

Safety GointPac/er

Slotted tailpipe

Debris sub

Tubin&

1irin& head

Safety spacer

DSTConcept

Tpical "#T or T0Ptool string


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Durin& the initial phase of the test, the$ellbore )uids, and, later, the drillin&)uid -#ud. that has in*aded thefor#ation in the *icinity of the $ellbore)o$ to surface( This is /no$n as thecleanupperiod( Cleanup is co#plete

$hen the $ell eHuent at surface isreser*oir )uid that contains no #udparticles or cuttin&s at surface(Once cleanup is co#plete, the #ain)o$period can be #aintained for theplanned duration, durin& $hich do$nhole

pressure #easure#ents and surface )o$rates are recorded( +t the end of the#ain )o$ period, the tester *al*e isclosed( 1or#ation pressure builds upa&ainst the *al*e $hile do$nhole

pressure #easure#ent continues(

DST Concept

asic operation:


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DST CONCEPT

TheEND

Dst Concept

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