The initiation fracture pressure
could be determined by the classical fracturing theory, which is influenced by in situ stress, rock strength; thus, it could be calculated by 
Nygaard, "Effect on fracture pressure
by adding iron-based and calcium-based nanoparticles to a nonaqueous drilling fluid for permeable formations," Journal of Energy Resources Technology, vol.
Nomenclature Dimensionless Variables: Real Domain [b.sub.Dpss]: Dimensionless pseudo steady-state constant [C.sub.fD]: Dimensionless artificial main fracture conductivity [p.sub.wD]: Dimensionless well bottom pressure [p.sub.2fD]: Dimensionless micro fracture pressure
in volume modification region [p.sub.wD]: Dimensionless artificial main fracture pressure
[q.sub.Dd]: Dimensionless decline rate [q.sub.Ddi]: Dimensionless decline rate integral [q.sub.Ddid]: Dimensionless decline rate integral derivative [t.sub.D]: Dimensionless time [t.sub.Dd]: Dimensionless decline time [x.sub.Di]: Midpoint of the i segment [gamma]: Euler constant, 05771.
The Geolog log-based pore pressure prediction module offers tools to predict pore and fracture pressure
profiles in wells based on logging data.
The authors have organized the main body of their text in twelve chapters devoted to drilling methods, drilling fluids, drilling hydraulics, well control and monitoring programs, formation pore and fracture pressure
estimation in drilling, the basics of drill string design, and a wide variety of other related subjects.
It consists of multiple horizontal wells and simultaneously injecting high volumes of steam above the rock fracture pressure
Previous research on formation stability shows that the empirical value of the formation fracture pressure
is 1.5 times the original formation pressure, and in this case, the high-pressure fluid may break through the roof .
The temperature-fluid-stress coupling model to analyze the granite's stability is established and simulated to figure out the temperature's influence on collapse pressure, fracture pressure
, and stress near the borehole, which can provide theoretical guidance for borehole stability and safety drilling in granite formations.
Where, [S.sub.b] is the swabbing pressure coefficient, g/[cm.sup.3]; [S.sub.g] is the fluctuation pressure coefficient, g/[cm.sup.3]; [DELTA][rho] is the additional drilling fluid density, g/[cm.sup.3]; [S.sub.f] is the safety value-added for the formation fracture pressure
, g/[cm.sup.3]; [S.sub.c] is the circulation pressure loss coefficient, g/[cm.sup.3]; [S.sub.k] is the allowable amount of kick, g/[cm.sup.3]; [DELTA]P is the allowable amount of sticking, MPa ; [h.sub.pmax] is the depth of the maximum formation pressure in the open hole section, m ; h is the well depth, m
If the fracture fluids are constantly replenished through seepage, the fracture pressure
will be maintained, which will continue the propagation process in this part of the fractures [25-27].
As the fractures are generally very thin and highly permeable compared to the surrounding matrix rock, the gradient of fracture pressure
normal to the fracture is negligible.
Figure 2(a) shows the fracture pressure
distribution surrounding the roadway with an initial gas pressure of 0.8 MPa, and Figure 2(b) shows the fracture pressure
distribution with an initial gas pressure of 1.5 MPa.