CHAPTER 2 (PART 1) Flashcards
•the pressure exerted by the formation fluids on the walls of the rock pores
•a critical parameter because it can affect drilling operations
Formation pore pressure
if the drilling mud pressure is less than the formation pore pressure, it can lead to ___, where formation fluids (oil, gas, or water) uncontrollably flow into the wellbore
blowout
FPP
Formation Pore Pressure
Normal formation pore
pressure also called as
hydro pressure
when the formation pore pressure equals the hydrostatic pressure of a full column of formation water
Normal formation pore
pressure (hydropressure)
Normal pore pressure is usually of the order of
0.465* psi/ft
Abnormal formation pore pressure also called as
geo-pressure
exists in regions where there is no direct fluid flow to the adjacent regions, these regions have impermeable boundaries, preventing fluid flow, trapping it to take a large proportion of the overburden stress
Abnormal formation pore pressure (geo-pressure)
abnormal formation pore pressure ranges between
0.8 and 1 psi/ft
Pressures ABOVE the normal range are called
overpressure
___ is determined through various methods, including well logs, seismic data, and drilling measurements
FPP
Pressures BELOW the normal pore pressure ranges are called ___
subnormal pore pressure
The terms ___ and ___ are used interchangeably because underpressures uncommonly occur in the sedimentary formations (excluding those caused by depletion from oil and gas production).
overpressure and abnormal pressure
What means TVD
True Vertical Depth
Elevated pore pressure s pose a severe risk during drilling when ___ are present and place important constraints on the density pf drilling mud (i.e. mud weights) used during drilling (Mark Zoback, 2007)
hydrocarbons
