Method and apparatus for determining characteristics of clay-bearing formations

Claim 1

A method of determining characteristics of shales in subsurface earth formations, comprising the steps of: determining the volume of clay contained in said subsurface earth formations; determining a first property related to the presence of exchangable cations of said shales in said formations; and determining a second property related to the potential clay swelling of said shales in said formations, said second property determined in response to said volume of clay and said first property.

Claim 2

A method of determining characteristics of shales in subsurface earth formations, comprising the steps of: determining the volume of clay contained in said subsurface earth formations; determining a first property related to the presence of exchangable cations of said shales in said formations; and determining a second property related to the potential clay swelling of said shales in said formations, said second property determined in response to said volume of clay and said first property.

Claim 7

A method of determining characteristics of shales in subsurface earth formations, comprising the steps of: determining the volume of clay contained in said subsurface earth formations; determining the cation exchange capacity of said volume of clay; determining the percent expandable layers of said shales in said formations in response to said volume of clay and the cation exchange capacity of said shales.

Claim 8

A method of determining characteristics of shales in subsurface earth formations, comprising the steps of: determining the volume of clay contained in said subsurface earth formations; determining the cation exchange capacity of said volume of clay; determining the percent expandable layers of said shales in said formations in response to said volume of clay and the cation exchange capacity of said shales.

Claim 12

A method for generally continuously determining formation characteristics throughout the vertical extent of clay-bearing formations, comprising the steps of: determining the volume of clay within said formations at a plurality of incremental depth horizons therein; determining the response of a first well logging apparatus within an environment composed essentially entirely of clay, said response determination made at a plurality of depth horizons directly related to said depth horizons at which said volume of clay determinations were made; said environment comprising clay types essentially equivalent to those found within said determined volume of clay at said depth horizons, said clay types in said environment in proportions generally equivalent to the relative proportions in which said clay types are found within said determined volumes of clay; determining the response of a second well logging apparatus within said clay environment; determining first characteristics of said formations generally continuously in response to at least one of said determined responses of said first and second well logging apparatus within said clay environment, said first characteristics include parameters of the bound water within said formations; determining second characteristics of said formations in response to said first characteristic, said second characteristics comprising the cation exchange capacity of said formations; and determining third characteristics of said formation in response to said second characteristics and said volume of clay, said third characteristics comprising an indicator of potential clay swelling.

Claim 13

A method for generally continuously determining formation characteristics throughout the vertical extent of clay-bearing formations, comprising the steps of: determining the volume of clay within said formations at a plurality of incremental depth horizons therein; determining the response of a first well logging apparatus within an environment composed essentially entirely of clay, said response determination made at a plurality of depth horizons directly related to said depth horizons at which said volume of clay determinations were made; said environment comprising clay types essentially equivalent to those found within said determined volume of clay at said depth horizons, said clay types in said environment in proportions generally equivalent to the relative proportions in which said clay types are found within said determined volumes of clay; determining the response of a second well logging apparatus within said clay environment; determining first characteristics of said formations generally continuously in response to at least one of said determined responses of said first and second well logging apparatus within said clay environment, said first characteristics include parameters of the bound water within said formations; determining second characteristics of said formations in response to said first characteristic, said second characteristics comprising the cation exchange capacity of said formations; and determining third characteristics of said formation in response to said second characteristics and said volume of clay, said third characteristics comprising an indicator of potential clay swelling.

Claim 15

A method of determining characteristics of the shales in shale-sand subsurface earth formations, comprising the steps of: determining the volume of clay contained in said subsurface earth formations; determining response indicies of a first well logging apparatus representative of a maximum and a minimum volume of clay; determining response indicies of a second well logging apparatus representative of a maximum and a minimum volume of clay; relating said maximum and minimum response indicies of said first well logging apparatus and of said second well logging apparatus; determining the cation exchange capacity of said volume of clay in response to said related response indicies of said first and second well logging apparatus and said determined volume of clay; and determining the percent expandable layers of said shales in response to said volume of clay and the cation exchange capacity of said shales.

Claim 16

A method of determining characteristics of the shales in shale-sand subsurface earth formations, comprising the steps of: determining the volume of clay contained in said subsurface earth formations; determining response indicies of a first well logging apparatus representative of a maximum and a minimum volume of clay; determining response indicies of a second well logging apparatus representative of a maximum and a minimum volume of clay; relating said maximum and minimum response indicies of said first well logging apparatus and of said second well logging apparatus; determining the cation exchange capacity of said volume of clay in response to said related response indicies of said first and second well logging apparatus and said determined volume of clay; and determining the percent expandable layers of said shales in response to said volume of clay and the cation exchange capacity of said shales.