| 摘要 |
A logging-while-drilling system for efficiently providing a reliable measurement of various petrophysical properties of subsurface earth formations. The logging-while-drilling system generally includes drilling a wellbore within an earth formation, circulating a fluid within the wellbore and injecting it inside the earth formation under pressure, taking a first measurement of the earth formation as altered by the injected fluid within the earth formation during an initial stage of drilling the wellbore, taking a second measurement of the earth formation as altered by the injected fluid within the earth formation during a later stage after the initial stage of drilling the wellbore and determining a zero-time state measurement of the earth formation from a combination of the first measurement and the second measurement, wherein the zero-time state measurement represents the earth formation prior to drilling the wellbore, and determining an infinite-time state measurement of the earth formation from another combination of the first measurement and the second measurement, wherein the infinite-time state measurement represents the earth formation as altered by the injected fluid within the earth formation, assuming the injection had continued indefinitely. Different combinations of the zero-time state measurement, the first measurement, the second measurement, and the infinite-time state measurement, are used to determine the petrophysical parameters of the earth formation, such as but not limited to, volumetric composition, permeability, wettability, and reservoir rock-type.
|
