Tight reservoir fluid characterization by using sonic slowness well logs
AssigneeSaudi Arabian Oil Company
InventorMohamed Amine Haceb
Life of this patent
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Abstract
Some implementations of the present disclosure provide a method that include: accessing a plurality of measurement logs taken from more than one well locations of a reservoir, wherein the plurality of measurement logs encode, for each well location, a plurality of parameters; based on applying a petrophysical model to the plurality of measurement logs, determining the plurality of parameters; based on a portion of the plurality of parameters, calculating a compressional formation slowness and a shear formation slowness; and predicting a fluid type at the more than one well locations of the reservoir based on combining the compressional formation slowness and the shear formation slowness with at least one of the plurality of parameters.
Claims18
A computer-implemented method to improve a computational accuracy and a computation time for predicting a fluid type within an unconventional tight reservoir, the computer-implemented method comprising:
- accessing a plurality of measurement logs encoding measurements taken from more than one well location of the unconventional tight reservoir, wherein the plurality of measurement logs comprise a neutron log, a gamma ray (GR) log, a log of bulk density, a log of sonic slowness, a log of resistivity, and a log of photoelectric measurements;
- in response to determining that a measured resistivity from the log of resistivity exceeds 31.62MΩ, determining, based on the plurality of measurement logs, a plurality of parameters that characterize a corresponding set of reservoir properties without determining an elastic rock property or a seismic velocity at the more than one well location of the unconventional tight reservoir;
- based on a portion of the plurality of parameters, calculating a compressional formation slowness and a shear formation slowness at the more than one well location of the unconventional tight reservoir;
- and
- predicting the fluid type at the more than one well location of the unconventional tight reservoir based on combining a ratio of the compressional formation slowness and the shear formation slowness with at least one of the plurality of parameters such that the fluid type is classified into one of two or more distinct categories and a production of hydrocarbon at unconventional tight reservoir is adjusted according to the classified fluid type, wherein the unconventional tight reservoir is characterized by the measured resistivity exceeding 31.62MΩ.
A computer system comprising one or more processors configured to perform operations of:
- accessing a plurality of measurement logs encoding measurements taken from more than one well location of an unconventional tight reservoir, wherein the plurality of measurement logs comprise a neutron log, a gamma ray (GR) log, a log of bulk density, a log of sonic slowness, a log of resistivity, and a log of photoelectric measurements;
- in response to determining that a measured resistivity from the log of resistivity exceeds 31.62MΩ, determining, based on the plurality of measurement logs, a plurality of parameters that characterize a corresponding set of reservoir properties without determining an elastic rock property or a seismic velocity at the more than one well location of the unconventional tight reservoir;
- based on at least a portion of the plurality of parameters, calculating a compressional formation slowness and a shear formation slowness at the more than one well location of the unconventional tight reservoir;
- and
- predicting a fluid type at the more than one well location of the reservoir based on combining a ratio of the compressional formation slowness and the shear formation slowness with at least one of the plurality of parameters such that the fluid type is classified into one of two or more distinct categories and a production of hydrocarbon at unconventional tight reservoir is adjusted according to the classified fluid type, wherein the unconventional tight reservoir is characterized by the measured resistivity exceeding 31.62MΩ.
A non-transitory computer-readable medium comprising software instructions that, when executed by a computer processor, cause the computer processor to perform operations of:
- accessing a plurality of measurement logs encoding measurements taken from more than one well location of an unconventional tight reservoir, wherein the plurality of measurement logs comprise a neutron log, a gamma ray (GR) log, a log of bulk density, a log of sonic slowness, a log of resistivity, and a log of photoelectric measurements;
- in response to determining that a measured resistivity from the log of resistivity exceeds 31.62MΩ, determining, based on the plurality of measurement logs, a plurality of parameters that characterize a corresponding set of reservoir properties without determining an elastic rock property or a seismic velocity;
- based on at least a portion of the plurality of parameters, calculating a compressional formation slowness and a shear formation slowness at the more than one well location of the unconventional tight reservoir;
- and
- predicting a fluid type at the more than one well location of the reservoir based on combining a ratio of the compressional formation slowness and the shear formation slowness with at least one of the plurality of parameters such that the fluid type is classified into one of three or more distinct categories and a production of hydrocarbon at unconventional tight reservoir is adjusted according to the classified fluid type, wherein the unconventional tight reservoir is characterized by the measured resistivity exceeding 31.62MΩ.
Dependencies are inferred from the claim text.