9 5/8" casing cement
10 March 2010
We drilled 12 1/4" to TD @ 2995m in cap rock and ran casing to 2994m and cemented same in place.After cement job and before cement get hard, observed pressure in annulus up to 1700psi. what can be the reason? We think that cement is not uniform dowhnole, Also what happened to water in hole after cement is set, since sometimes we see water in cement samples.
We did had similar issue while cementing the intermediate casing and annulus was showing pressure at the surface, we used to bleed it initially, but later on we did an remedial cement job and were able to stop gas migration.
Thanks for your responsenad guidelines. It was the expansion of cement while setting. after cement got hard we released pressure and never increased again.
Rgds and be safe
Mohammed is exactly correct, gas migration for a variety of reasons is quite common. There is an excellent article in the January 2010 issue of World Oil dealing with this very subject.
Good luck and stay safe,
Baker Hughes Drilling Fluids
Amir, greeting from the Joker (Iran Keps)- to give you any real assistance more information is needed.
Mud weights in hole pre-cement job
WBM or OBM
Basic cement pumping schedule volume & weights
Any variations in pressure during pumping cement.
Any issues with cement plugs?
Any significant losses while drilling?
Snr Drilling Supt
This has been seen in many cases which is mainly due to the transition time of slurry from the fluid phase to solid state in which cement slurry starts to loose itÃ¢â‚¬â„¢s hydrostatic and itÃ¢â‚¬â„¢s not set yet so the high pressure Gas/oil start to migrate into the annulus.
To prevent this, every cement company has its own product and solution which is basically an additive to accelerate this transition time and make it a right angle set. GasBlok ( Dowell) and MicroBlock ( Halliburton ) are the main ones which I know.
You may find this paper useful: