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Drillpipe and Bottom Hole Assembly - Standards

This article describes the standards for Drillpipe and Bottom Hole Assembly (BHA).

Pipe Tally Requirements

Master Drillpipe Tally Book

  • The master drill pipe tally book shall be kept by the Driller in the dog-house and in the Tool Pusher office. This is to be updated every tour.
  • Both the drill pipe single and stand columns shall be totalled vertically and compared to the cumulative total.
  • When the totals show no discrepancy, the column is to be initialled by the driller on tour.
  • The Contractor Toolpusher will make a daily check and also initial the totals.
  • When drilling or reaming, connection depths shall be written on the Geolograph record at the time of the connection.
  • The Contractor toolpusher shall make a physical check of the total drill pipe on hand daily.
  • Drill pipe checks shall be made at each trip before and after reaching casing depths.
  • Each individual drilling tally assembly item shall be annotated.
  • All drill pipe RIH to be drifted as per API.

 

Drillpipe

  • The Drilling Supervisor is responsible to ensure the following points:
  • Any new pipe (including HWDP) must be checked and formally accepted/rejected against contract requirements.
  • The hardfacing must comply with requirements and be in an acceptable condition.
  • The drillpipe must, as a minimum, meet premium specifications.

Bottom Hole Assemblies

  • The submerged BHA weight is the weight of the drill collars only. When a jar is included in the string it is the submerged weight of the drill collars below the jar.
  • The Hevi Weight Drillpipe is not included in the weight of the BHA, unless a minimal assembly is used where the HWDP is planned to apply the weight on bit.
  • The attached BHA’s are recommendations and the Drilling Supervisor should use his own judgement to determine the correct number of drill collars.
  • Do not install a stabiliser next to a crossover. (The cause of most failures of crossovers and stabiliser connections is misalignment of the tooljoints). Stabilisers with eccentricity between the connections and the blade OD will also suffer early fatigue failure.
  • When PDC bits are run, a shock sub should not be included in the BHA but a drilling jar should be included.
  • Avoid in general the use of too many connections next to each other. (Homogenous load distribution to be considered)
  • Do not run more DCs than required.
  • Do not run a jar as standard, but only if required. (Jar, if required, to be installed at optimum position, ie. one DC between jar and HWDP).
  • No safety joints shall be run in drilling assembly
  • Shock subs are more flexible than DCs, especially 6 ¼in: and smaller sizes.
  • Do not run a different assembly on a check trip during logging or prior to running casing than the one used for drilling.
  • Do not run stabilisers, which are more than ¼in undergauge as one of the bottom three stabs in a packed hole assembly.
  • Do not change assemblies halfway. Time consuming reaming results in deteriorating hole conditions with a risk of sticking the assembly mechanically.
  • Ensure that all assembly items have the required bore back and stress relief grooves prior to use.

Weight on Bit

The Maximum WOB is 75% - 90% of the submerged BHA weight.

Limit WOB to 75% when drilling is rough.

Increase WOB to 90% when drilling is smooth.