Method for determining formation parameters

Claim 1

A method for determining formation parameters at predetermined depths in a borehole in a zone of interest in the formation, the method comprising: determining the thermal neutron capture cross section of a first injected fluid ( Sigma w1); determining the thermal neutron capture cross section in the formation zone of interest flooded with the first injected fluid ( Sigma 1); determining the thermal neutron capture cross section of a second injected fluid ( Sigma w2); determining the thermal neutron capture cross section in the formation zone of interest flooded with the second injected fluid ( Sigma 2); determining the effective porosity ( phi e) at predetermined borehole depths utilizing the determined values of ( Sigma w1), ( Sigma w2), ( Sigma 1) and ( Sigma 2); determining the formation neutron porosity ( phi n); determining the porosity of the shale component of the formation ( phi sh); and determining the formation fraction of bulk volume that is shale ( Rho ) utilizing the algebraic expression: Rho phi n phi e/ phi sh.

Claim 2

A method for determining formation parameters at predetermined depths in a borehole in a zone of interest in the formation, the method comprising: determining the thermal neutron capture cross section of a first injected fluid ( Sigma w1); determining the thermal neutron capture cross section in the formation zone of interest flooded with the first injected fluid ( Sigma 1); determining the thermal neutron capture cross section of a second injected fluid ( Sigma w2); determining the thermal neutron capture cross section in the formation zone of interest flooded with the second injected fluid ( Sigma 2); determining the effective porosity ( phi e) at predetermined borehole depths utilizing the determined values of ( Sigma w1), ( Sigma w2), ( Sigma 1) and ( Sigma 2); determining the formation neutron porosity ( phi n); determining the porosity of the shale component of the formation ( phi sh); and determining the formation fraction of bulk volume that is shale ( Rho ) utilizing the algebraic expression: Rho phi n phi e/ phi sh.

Claim 4

A method for determining formation parameters at predetermined depths in a borehole in a zone of interest in the formation utilizing field determined data obtained from the tool responses of logging tools run in a borehole in the formation, the method comprising: determining the thermal neutron capture cross section of a first injected fluid ( Sigma w1); injecting the first injected fluid in the formation zone of interest to substantially flood the formation zone of interest with the first injected fluid; running a first logging tool in the borehole in the formation having a tool response indicative of the formation thermal neutron capture cross section; determining the thermal neutron capture cross section at predetermined borehole depths in the formation zone of interest flooded with the first injected fluid ( Sigma 1) utilizing the tool response of the first logging tool; determining the thermal neutron capture cross section of a second injected fluid ( Sigma w2); injecting the second injected fluid in the formation zone of interest to substantially flood the formation zone of interest with the second injected fluid; running a second logging tool in the borehole in the formation having a tool response indicative of the fOrmation thermal neutron capture cross section; determining the thermal neutron capture cross section in the formation zone of interest flooded with the second injected fluid ( Sigma 2) utilizing the tool response of the second logging tool; determining the effective porosity ( phi e) at predetermined borehole depths in the formation zone of interest utilizing the determined values of ( Sigma w1), ( Sigma w2), ( Sigma 1), and ( Sigma 2); and determining the thermal neutron capture cross section of the formation in the formation zone of interest of the formation and shale ( Sigma r) utilizing the algebraic expression: Sigma r ( Sigma 1 Sigma w2 - Sigma 2 Sigma w1/( Sigma w2 - Sigma w1) - ( Sigma 2 - Sigma 1)).

Claim 5

A method for determining formation parameters at predetermined depths in a borehole in a zone of interest in the formation utilizing field determined data obtained from the tool responses of logging tools run in a borehole in the formation, the method comprising: determining the thermal neutron capture cross section of a first injected fluid ( Sigma w1); injecting the first injected fluid in the formation zone of interest to substantially flood the formation zone of interest with the first injected fluid; running a first logging tool in the borehole in the formation having a tool response indicative of the formation thermal neutron capture cross section; determining the thermal neutron capture cross section at predetermined borehole depths in the formation zone of interest flooded with the first injected fluid ( Sigma 1) utilizing the tool response of the first logging tool; determining the thermal neutron capture cross section of a second injected fluid ( Sigma w2); injecting the second injected fluid in the formation zone of interest to substantially flood the formation zone of interest with the second injected fluid; running a second logging tool in the borehole in the formation having a tool response indicative of the fOrmation thermal neutron capture cross section; determining the thermal neutron capture cross section in the formation zone of interest flooded with the second injected fluid ( Sigma 2) utilizing the tool response of the second logging tool; determining the effective porosity ( phi e) at predetermined borehole depths in the formation zone of interest utilizing the determined values of ( Sigma w1), ( Sigma w2), ( Sigma 1), and ( Sigma 2); and determining the thermal neutron capture cross section of the formation in the formation zone of interest of the formation and shale ( Sigma r) utilizing the algebraic expression: Sigma r ( Sigma 1 Sigma w2 - Sigma 2 Sigma w1/( Sigma w2 - Sigma w1) - ( Sigma 2 - Sigma 1)).