Most Read

Latest

Best Practices - Drilling 26" section

26” Section - Preparation

In addition to the items specified in the pre-spud section, the following preparation and checks will be performed:

  • Pre-cut conductor from ground level. Keep attached in 4 areas with 2” tabs. Install 30” dresser sleeve.
  • Test all mechanical surface equipment (Mud Engineer and solid control personnel to check all Mud equipment and inform Drilling Supervisor of any deficiency).
  • Pressure test cement and standpipe lines to 7500psi.
  • DSV will carry out Rig acceptance checks (Test Top drive functions as per test procedure).
  • DSV to verify distance from RTE (Rotary Table Elevation) to AGL (Above Ground Level, i.e. Top Cellar) once rig is rigged up. This height is to be reported to the Operations Drilling Engineer.
  • Gauge of all stabilizers will be checked prior to making up the BHA. Prior to drill out, the Drilling contractor will provide an accurate BHA report including serial numbers and dimensions of all the components.
  • Prepare 20” Casing on racks (Check shoe jt for any debris inside, install centralizers on stop collars as per tally).
  • Confirm cellar jet pump installed and tested.
  • Confirm Cement stinger/Centralizer/spare seals on location.
  • Confirm 20 ¾” Well head housing M/U with landing joint flange and 5”DP.
  • Confirm Wellhead orientation drawing on location.
  • Confirm Thread lock compound in DSV office.
  • PU 3 x 8 ¼” D/C, and 15 x 5 ½” DP and rack back (Check well centre with 8” D/C stand before rack back).
  • Losses are not expected in this section. However sufficient LCM material should be available at the wellsite.
    • Ensure the weights (in air and mud) of the BHA and maximum pull is clearly visible to the Driller.

26” Section – Sequence of Operations

  • Hold Pre-Job safety meeting. Discuss with crew the Drilling Contractor Shallow Gas Procedures
  • Make up the 26” rotary BHA. Include a float valve.  Ensure that a Totco ring is installed.
  • Circulate through BHA and report weight in DDR.
  • RIH with the 26” BHA inside the 30” Conductor.
    • The 30” conductor has been pre-installed to a depth of approximately 10-12 m below top cellar.
  • Drill out the 30” shoe, and carefully clean out the rathole in case of cement blocks.  Use a lower flow rate when around the 30” shoe area to avoid washing out the shoe.
    • To prevent washout under the shoe, the flow rate will be limited to 2200 LPM until the bit is 5m below the shoe. The flow rate is then increased to 2400 LPM to drill the first 30m and to 3000 LPM for the rest of the section.
  • Drill ahead to 20” casing point, allowing for a 3 m rathole below the 20” shoe. The exact depth of section TD will be adjusted to space out the casing.
    • ­Drill water and viscous sweeps to be used for drilling this section pump a sweep prior to making connections. Add additional sweeps as required. Ensure sweeps of sufficient size to clean hole. The basic mud plan is to drill with water in a closed circulation system, the formation will provide a native mud which will be maintained as per the mud program.
    • ­­Report in the DDR the shape and size of cuttings as well as the % increase in cuttings when circulating hi-vis pills.
    • Ensure mud specifications are as per mud programme.
  • At TD sweep hole with 10m3 Hi Vis and circulate clean.

  • Perform wiper trip by POOH bit to 30” csg shoe (DSV / Toolpusher will be on Rig floor).

  • RIH, wash last +/-10 metres @ 20SPM to avoid plugging of nozzle and confirm any fill (increase to full flow rate and clear fill).

  • Sweep hole with 10m3 Hi Vis and circulate clean @220SPM.

  • Drop Totco.
    • If severe hole problems occur run the Totco barrel on the rig’s slick line.
  • Pump out of hole.
    • Use high flow rates while pumping out of hole with mud in order to reduce the risk of fill.
    •  If inclination is greater than 1° then ream down the hole to section TD in an attempt to reduce the inclination. Confirm this step with the Drilling Superintendent.

  • Drain riser into cellar and clear cellar with jet pump or vacuum truck (if available).

  • Disconnect dresser coupling and cut 30” conductor (ensure Hot work Permit obtained).
    • If possible PU Weatherford equipment.
  • Lay down riser.