The workflow of the conventional 1-D Petroleum System Modeling (PSM) was proposed and applied to assess the Sembar maturity, comparative retention capacity, remaining kerogen, formation pressure
and the remaining volume of the hydrocarbon (oil and gas) in shales of the Sembar Formation.
Increased formation pressure
causes fractures in caprock, and C[O.sub.2] escapes from the aquifer to overburden rock.
where [C.sub.r] is rock compressibility when the effective stress is [[sigma].sub.eff], [MPa.sup.-1]; [C.sub.ro] is original rock compressibility, [MPa.sup.-1]; [[sigma].sub.eff] is effective stress, [[sigma].sub.eff] = [p.sub.over] - p, MPa; [p.sub.over] is overburden formation pressure
, MPa; and p is formation pressure
Field Variables A: Reservoir drainage area, [m.sup.2] [c.sub.2m]: Compressibility for matrix, 1/Mpa [c.sub.2f]: Compressibility for micro fracture, 1/Mpa [[phi].sub.2m]: Porosity for matrix, fraction [[phi].sub.2f]: Porosity for micro fracture [k.sub.f]: Permeability of artificial main fracture, mD [k.sub.2f]: Permeability of micro fracture, mD [k.sub.2m]: Permeability of matrix, mD p: Formation pressure
, Mpa [p.sub.i]: Initial formation pressure
, Mpa r: Reservoir radius, m [r.sub.e]: Equivalent drainage radius, m t: Time variable, days [x.sub.f]: Fracture half length, m w: Fracture width, m [w.sub.2]: Elastic storativity ratio, fraction [[lambda].sub.2]: Crossflow coefficient, fraction.
Drilling a well sometimes involves traveling down through sealed and pressurized formations, and it's important to keep the mud weight greater than any potential formation pressure
, Davies says.
Drilling muds and fluids are chemical systems used to lubricate the drill bit, to control formation pressure
, and to remove formation cuttings.
Glycols or methanol can be injected into the process stream and must come in contact with the condensed water prior to achieving hydrate formation pressure
They identify and analyze ground water chemical composition, its variations, and its distribution patterns in the natural reservoirs; study the nature and spatial occurrences of abnormally high formation pressure
and abnormally high pore pressure in the subsurface of unbalanced folding in the mobile belts; and consider the role such abnormalities play in the formation of faults, regional and local structures, hydrocarbon migration and accumulation, and the preservation and dissipation of hydrocarbon accumulation.
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 drilling mud when circulated becomes in contact with the formation at very high pressure and tends to damage it apart in- addition to controlling the formation pressure
Based on the material balance equation in the water drive gas reservoir, the relationships between average formation pressure
and geologic reserve, cumulative gas production and water invasion intensity can be obtained in (12) 17]
Furthermore, the conventional methods can be used to analyze this restored formation pressure
to estimate formation parameters.