Mears 24” Gas Line
- Project was completed successfully with no substantial IR’s and whole fluid disposal was limited to two loads only during drilling & reaming.
- Pullback of product pipe was very smooth at low forces indicating good hole conditions were created.
DTE Gas Company Southfield Bore 24” Main Replacement
2,654’ of 24” Steel Pipe
24” Ream Pass
36” Ream Pass
What made this Complex
Wide Range of soil conditions including silt, clay, sand and sandy gravel. Clays were highly reactive and dispersive.
Clays of this nature lead to excess viscosity, increased rotational torque and build up of fine solids causing increased mud weights. These conditions lead to high annular pressures and inadvertent returns typically solved with dilution and haul-off of whole drilling mud.
How Sentinel Solved It
Understanding the formation and how to address the need for suspension of heavy sands and gravels while dealing with reactive clays was the basis for Sentinel’s selection. Clays and fines were dealt with using Sentinel’s Lynx 500 centrifuge. The 20”x80” centrifuge was run at the lowest differential setting possible during the pilot to maximize the cutpoint. During ream passes, differential settings were increased to maintain flowrate while handling the higher solids loading. Mud weights were kept under control and limited haul off of whole muds due to the high flowrates processed through the Lynx 500 centrifuge.
Drilling fluids were supplied to maintain an inhibitive nature using PHPA’s and PAC’s. Soda ash, bentonite and xanthan were used to boost the fluids ability to suspend and carry heavy sands and gravels out of the bore.