Most Read

Latest

8.5in Section Drilling - Best Practices

8 ½” Section Preparation checklist

  • Drilling Engineer is to organise pre-section meetings at the rig site, with rig and office personnel to discuss section objectives and hazards.
  • Confirm primary and contingency bits (including milled tooth and insert tri-cone) are available on location.
  • Confirm hydraulics and bit nozzle requirements with Operations Engineer and dress bit accordingly.
  • Gauge all stabilizers and check connections of all BHA components. Prior to RIH, the Drilling contractor will provide an accurate BHA report including serial numbers and dimensions of all the components.
  • Confirm that any activation balls/darts (e.g. for PBL circulating subs and drop-in dart subs) are the correct size and will pass through all BHA components and DP crossovers.
  • Activation balls/darts should be kept in an obvious place in the dog house.
  • Non ported float valves to be used.
  • The Directional Driller and LWD Engineer will discuss with Tool pusher how best to pick up BHA to minimise excessive handling and time. The BHA components should be laid out on the catwalk and numbered in order of pick up.
  • The bend on the steerable motor and the tool face offset must be verified by the DD, MWD Engineers and the Drilling Supervisor.  The tool face offset must correctly entered into the MWD computer and a hard copy passed to the drilling supervisor.
  • If using a steerable motor ensure a Turboback stabiliser is also run.
  • Ensure all the technical specifications and dimensions (i.e. checklists) of the drilling tools are presented to DSV.
  • Ensure the following information is available in the doghouse: Jar settings, weights (in air and mud) of the BHA and maximum pull.  Note that the pull to activate the jars will be higher once the BHA is in the kick-off and tangent section.
  • Liners size must be optimized for flow rates and pressures.
  • Wash pipe seals should be changed.
  • The instructions describing the well shut-in procedures will be posted in the dog house, drilling supervisor and tool pusher’s offices.
  • The following information is available in the doghouse, drilling supervisor and tool pusher’s offices: FIT, LOT, MAASP, casing burst pressures, Well Control datasheet.
  • Mud Loggers to ensure that all ditch magnets are cleaned and re-installed in the header box. Metal recovered should be reported daily, as ‘metal recovered (grams) per total revs and reported in the DDR.
  • Mud Loggers to check and calibrate all sensors (gas, pit volume, pump stroke, torque, WOB, rpm etc).

8 ½” Section - Sequence of Operations

  • Perform 9 7/8” x 9 5/8” casing pressure test to 5000 psi (345 bar) if this was not done after cementation.
  • Pick up the directional drilling tools and make up the BHA.

Note: There is NO requirement to function test the circulating sub. Visually inspect bypass ports for evidence of washing.

  • Surface test the steerable motor drilling system and MWD and RIH with 8 ½” BHA.
    • - Ensure that the Directional Driller witnesses the correct toolface offset being entered into the MWD computer and a sign off form completed.
    • - Confirm no leakage from the circulating sub. Note there is no requirement to function test on surface.
  • Perform a full test of the M/LWD tools at approx 500m. Thereafter it is not necessary to test the tools however pulses may be seen during filling the DP.
  • Circulate through BHA and record weight in DDR.
  • Before drilling out the shoe track a strip drill and a kick drill must be performed. The operation of remote (automatic) and manual choke valves, gauges must be tested by circulating mud through the choke manifold keeping +/- 200psi back pressure on choke.

Note: blow out all lines after drill

  • Wash down the last stand(s) and tag top of cement inside 9 7/8” casing.
  • Drill out cement and 9 7/8” float equipment using mud from the previous section. While drilling out the shoe track, displace to recover the previous mud such that the displacement is complete by the time the shoe has been drilled.
    • - Mud Engineer to be on tanks during displacement
    • - At least 3 vacuum trucks to be on location
  • Clean out the casing rat hole and drill 3 m of new formation.
  • Pull the BHA back inside the 9 5/8” casing shoe and perform a shoe integrity test at 1.6 s.g. EMW. If leak off occurs below 1.6 s.g. consult with the Drilling Superintendent.
    • - Report in DDR maximum pressure, volume pumped and bled off.
  • Commence drilling 8 ½” section.
  • If losses are experienced inform Drilling Supervisor and adhere to these guidelines:
    • - Ensure LCM is thoroughly mixed before pumping
    • - Follow the LCM decision tree for severity of losses
    • - If not in producing zone more aggressive LCM can be utilised – confirm with Fluid Engineer.
  • Borehole conditions will be closely monitored as drilling progresses. The following guidelines should be adhered to:
    • - Closely monitor for losses/gains – inform Drilling Supervisor immediately and report on DDR.
    • - Flow check all drilling breaks and report same on the DDR.
    • - Monitor connection gas and report in the DDR.
    • - Maintain mud rheology within specification.  Discuss changes with Drilling S- perintendent.
    • - Prior to a connection, circulate and rotate to ensure the cuttings are lifted well above the BHA. 
    • - Wipe the hole at connection in order to detect changes in the hole condition. The driller will keep a log of the string weight (up, down and rotating), in order to monitor trends.
    • - Acquire LWD log reaming down – do not back ream.
  • Prior to trip, pump a hi-vis pill and circulate clean. Up to 3 times bottoms up shall be considered for hole cleaning before tripping. Perform wiper trip if required.
  • If changing BHA to run back in with full LWD suite remove RA sources, perform the BHA change. Then read and initialise the LWD tools at the same time.
  • Prior to logging the build-up section, check with Schlumberger if logs can be recorded by wire line when the inclinations ranging (20 - 30 degrees).
  • At section TD prior to final trip out of hole to run liner perform the following:
    • - Increase mud density to equivalent ECD.
    • - Perform swab test.
    • - Pump out of hole to kick off point at full drilling flow rate.
  • Ensure the trip sheet is correctly filled in by the Tool pusher. The theoretical volumes should be validated by the Drilling Supervisor and Mud Logger
  • Drift all drill pipe, drill collars and crossovers to API specification to ensure pump down plug (2.250”) and setting ball (1.50”), will pass freely (minimum drift size 2-3/8”).
  • Record up and down weights and torque values at 20 and 30 rpm at TD, KOP and at the proposed hanger setting depth.  Record on the daily drilling report. This will give an approximate guide for releasing the liner running tool. 
  • Record accurately the hole condition during the trip, i.e. tight spots (bit depth and amount of o/pull), back reaming, circulating, etc. Compare with the mud log / wire line log to determine if hole condition can correlate with formation type.
  • Break off the bit and rack back the drilling BHA. 
  • Gauge all stabilisers and report in DDR.
  • If logging is performed, the following information will be reported in the DDR for each run:
    • - Time to rig up, assemble and calibrate tool
    • - Time spent in hole
    • - Tool failures and lost time
    • - Depth tool reached
    • - Maximum recorded temperature and time since last circulation.
    • - Logger shoe depth
    • - Rig down logging equipment. 
  • Perform wiper trip if required. 
  • Rig up to run 7” liner.