Abstract: Methods (and related apparatus) include obtaining data regarding a measured property. The measured property includes an amount of each of predetermined hydrocarbons in a gas sample extracted from drilling fluid exiting a wellbore having a hydrocarbon resource. An unknown characteristic of an investigated fluid property of the hydrocarbon resource is predicted utilizing the obtained input data and one or more predetermined models each built via statistical classification and regression analysis of a preexisting database containing records. Each record includes known characteristics of fluid properties of a different one of known reservoir fluids. The fluid properties include the investigated fluid property and the measured property. The investigated fluid property includes a fluid type of the hydrocarbon resource, an amount of at least one additional hydrocarbon, gas-oil ratio, or stock tank oil density.

Abstract: Methods (and related apparatus) include obtaining data regarding a measured property. The measured property includes an amount of each of predetermined hydrocarbons in a gas sample extracted from drilling fluid exiting a wellbore having a hydrocarbon resource. An unknown characteristic of an investigated fluid property of the hydrocarbon resource is predicted utilizing the obtained input data and one or more predetermined models each built via statistical classification and regression analysis of a preexisting database containing records. Each record includes known characteristics of fluid properties of a different one of known reservoir fluids. The fluid properties include the investigated fluid property and the measured property. The investigated fluid property includes a fluid type of the hydrocarbon resource, an amount of at least one additional hydrocarbon, gas-oil ratio, or stock tank oil density.

Abstract: Methods (and related apparatus) include obtaining data regarding a measured property. The measured property includes an amount of each of predetermined hydrocarbons in a gas sample extracted from drilling fluid exiting a wellbore having a hydrocarbon resource. An unknown characteristic of an investigated fluid property of the hydrocarbon resource is predicted utilizing the obtained input data and one or more predetermined models each built via statistical classification and regression analysis of a preexisting database containing records. Each record includes known characteristics of fluid properties of a different one of known reservoir fluids. The fluid properties include the investigated fluid property and the measured property. The investigated fluid property includes a fluid type of the hydrocarbon resource, an amount of at least one additional hydrocarbon, gas-oil ratio, or stock tank oil density.