Tripping and Reaming Practices

Terminology

Drag or over pull : During POOHHeld up or set down : During RIHHook load = String wt in mud + Block wtIf the present hook load is more than the last

hook load, then it is over pull or dragIf the present hook load is less than the last hook

load, then it is held up or set downDrag experienced in directional well

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Good reaming practices

Ream clear the drilled section before making connection.

Rotate string to clear cutting bed in high angle sections.

Problematic formations to be control drilled to plug pores and avoid annulus loading.

Keep eye on torque. Very high and abrupt torque are observed. Ream patiently and avoid giving WOB. When torque fluctuation subsides, ream ahead

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Good reaming practices (contd)In open hole d/string be kept in motion all time.Monitor / record / analyze & clear, if possible the

up & down drags. Circulate & clean hole thoroughly before POOH.Never force string out or in with sustained up &

down drag- Clear all tight spots patiently.Use correct WOB from earlier experience to

avoid severe torques

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Contd.Always wash down last single/stand of DP to

bottom.Swabbing means tight hole- liquidate it before

further POOH.Normally while reaming pump discharge should

be same as discharge during drilling.After reaming a portion make sure cuttings are

circulated above BHA before picking up string.As far as possible allow only downward motion of

string after pipe connection.

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OthersIf torque is trapped in the string release slowly to

avoid un-screwing of d/string.While handing over charge, shift in charge to pass

on all information regarding well behavior.Reaming should be done only if un-avoidable.Well angle build up/ drop to be handled with great

care.BHA change to be avoided in one section if not

necessary.Record OD, ID & lengths of all components of stringKeep an accurate record of pipe tally.Never snap wire line from rope socket of a stuck

wire line tool.6

Tripping through a tight hole

Don’t try to push thru tight spots while tripping.Ream / back ream to clear tight spots while

tripping in / tripping out.Don’t ever apply over pull on a tight spots while

pulling out. Try to push down in compression.Don’t apply set down weight on hold ups while

tripping in. Apply over pull.

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General guidelines for tripping / reaming

POOH first 5 stands slowly to avoid swabbing If POOH very fast, string may get stuck

permanentlyIf POOH slowly, gives time to react and avoid

getting stuckHave a good check on hole fill upIf all OK, proceed to POOHPOOH speed not to be too fast in Open hole.

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General guidelines for tripping / reaming

Minimum required circulation time should be

given before tripping out.Don’t pull thru gradually increasing up-drag.Varying mud properties indicate problem in the

well.Sufficient pump discharge should be given before

tripping out / during reaming.reaming rate should be slow.

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Wiper trip & short tripThickness of mud cake in the well is time

dependent also.Wiper trips help in sizing thickened mud cake up

to casing shoe and maintain the gauge of the hole..

It also helps in evaluation of well cleaning status & condition.

Wiper trip is recommended every 24 hrs or 200-300 m of drilling whichever is earlier.

Based on specific well / area experience the duration can be increased.

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Contd.Short trips may be done to evaluate the freshly

drilled hole section.It may not help in evaluating the entire open hole

section up to casing shoe.Before wiper trip enough mud circulation should

be given to clean the cuttings from the well.Before short trip also ,especially in a directional

well, sufficient mud circulation should be given to clean the well off drilled cuttings.

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Wiper tripString pulled out from bottom to last casing shoeRecommended before running casing or loggingGives time for formation to react & come into wellIf recommended, do not avoid wiper trip as it may

help in detecting problematic areaIf held up repeatedly experienced during wiper

trip and lot of reaming is carried out, consider another wiper trip before final POOH

Wiper trip also recommended while drilling with PDC bits. ROP is faster and bit needs cooling time to avoid overheating and damaging PDC compacts

Always keep watch on over pulls during wiper tripIf equipment failure, make wiper trip and repair

equipment12

Short trip

String pulled out from bottom by a few stands say, 5 stands. String is not pulled out from bottom to last casing shoe

String is pulled above the problem zone and run back to bottom immediately. No waiting time in OH

Recommended repeatedly when drilling a long hole with PDC or other high performance bits

Recommended when over pulls or held ups experienced frequently during drilling

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Trip tank: Hole fill upAlways use during POOHNote down mud taken by hole for every 5

stands (For 5” DP, say 0.1 cu m for one stand) If hole taking required mud, everything OKIf hole taking more than required mud, mud

loss or mud being lost on surfaceIf hole taking less than required mud, well kick

or flow into the wellFor 6-1/2” DC, say 0.25 cu m for one stand For 8” DC, say 0.5 cu m for one standBe very alert during D C pulling out, fill after

every stand14

Mud pump for filling hole

Not recommended but can be usedCheck flow line for return flow and see no of

strokes for calculating amount of mud requiredDo not run pump too fastUse hole fill mode during trip to count mud

strokes as it stops counting mud strokes as soon as flow is detected though pump keeps on running

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LOT

To measure strength of formation below casing shoe as it is expected that this will be the weakest formation in the next phase of open hole.

May be true and may not be trueNever use mud pump for thisUse only cementing unit as it can pump at

slow rate and amount of mud pumped and returned can be measured accurately

Will help in deciding max MW possible in the new phase of drilling

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