This message has been cross posted to the following Discussions: Research and Development and Drilling .
-------------------------------------------
Good day all,
I bring you compliments of the day.
Hard Shut-in of the BOP have been argued over time to cause a pressure increase on the formation which might cause a fracture and the pressure increase is defined to be transmitted in a wave like manner while for Soft Shut-in, an increase in the volume of kick is estimated.
My point of interest is developing a mathematical model to estimate how much in psi is this pressure due to hard shut in of the BOP and compare it to the pore pressure and fracture gradient plot to know actually and be fully confident that it is safe during hard-shut in operation and at the same time, the formation will not be stressed to the point of fracture.
Though several experimental real time operations with instruments has been carried out on this by the Amoco/Schlumberger group.
The main equations that relate this concept are the change in pressure Magnitude equation by Joukowsky, equation of motion/momentum and the continuity equation.
These various equations are modeled for a pipe line system where these water hammer effect is also observed.
The constrain here is relating these model to a vertical well bore with characteristics of a rock material and not a steel or tunnel as the case given by Streeter and Wylie 1967. The boundary condition on water hammer discusses pumps, valves, orifice etc and their formation but my concern is
1. flowrate as a specified function of time at upstream end
2. series connection at the junction of casing pipes with different diameter, roughness, and thickness
3. a porous media/formation at the downstream end of the well, i.e a depth beneath the BOP.
My challenge is number 3, i am hooked here. could any professional help me.
Thank you and GOD bless you.
------------------------------
Supreme Isele
PTI STUDENT (PETROLEUM ENGINEERING)
WARRI, NIGERIA
------------------------------