Horizontal Directional Drilling

[SJcivil]

Has anyone had experience with stabilizing the area outside the directional drilled pipe. The normal drilling mud is documented as providing little to no support to the pipe. Therefore, it is hard to make ring deflection calculations work for normal pipe design. I was wondering if an acceptable prcatice is to pressure grout around the exterior of the pipe after it is in place. Or maybe add a late setting cement or grout to the drilling mud which would stabilize the soil directly outside the pipe. Anyone else encountered this problem?

 

[Unotec]

Change the mud. The mud man should be able to tailor it so that the wellbore will be stabilized. You'll probably have an approach with mud chemistry and mud weight/pressure. What type of formation is that you cannot stabilize it with 'normal' mud? What is that you call 'normal'?

<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying ” Damn that was fun!” - Unknown>>

 

[Zambo]

unotec,

unless I'm very wrong you are talking about a different application than SJCivil. I believe you are discussing a directionally (vertically) drilled well whereas the topic is regading a horizontally directionally drilled pipeline. The pipeline is a permanent installation that SJCivil is concerned will be affected by the continued prescence of the driling fluid

 

[Unotec]

Thanks Zambo. Yes, I had to re-read the post. Sorry, up here drilling has one strong incline into oil & gas wells.

<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying ” Damn that was fun!” - Unknown>>

 

[bimr]

The drilling mud is supposed to do that.

"Stabilizing the bore path, especially in loose or soft soils, by building a low-permeability filter cake and exerting a positive hydrostatic pressure against the bore path wall. The filter cake and positive hydrostatic pressure reduce obstruction of the bore path and prevent formation fluids (i.e., groundwater) from flowing into the bore, or drilling fluids from exiting the bore path into the formation (loss of circulation)."

http://www.dipra.org/pdf/HDD-brochure.pdf