Method for defining a representation of a hydrocarbon reservoir

A device for determining a representation of a hydrocarbon reservoir, the device comprising at least one computation unit, wherein the at least one computation unit is configured to use geological models constructed from a group of parameters to estimate static hydrocarbon volume values in the reservoir, a number of mutually independent sources of uncertainty being taken into account, at least some of the sources of uncertainty being associated with respective parameters of the group, the representation of the hydrocarbon reservoir consisting of a geological model determined to give rise to a target value of the static volume of hydrocarbons, wherein the at least one computation unit is further configured to execute the steps of:

• selecting a base case for each source of uncertainty taken into account;
• for each source of uncertainty taken into account, estimating a probability law for the static volume of hydrocarbons using models in which said source of uncertainty varies while the other sources of uncertainty conform to their respective base cases;
• constructing a conversion table comprising a set of rows, each having, for each source of uncertainty taken into account, a respective quantile value corresponding to a volume value according to the probability law estimated for said source of uncertainty and further having a resultant value of the static volume of hydrocarbons calculated as a function of the volume values associated with the quantile values of the row;
• selecting a row of the conversion table having a resultant value of the static volume of hydrocarbons equal or closest to the target value of the static volume of hydrocarbons;
• and
• setting the sources of uncertainty according to the respective quantile values thereof in the selected row of the conversion table to construct the geological model forming the representation of the hydrocarbon reservoir.

A computer-readable memory medium having a computer program code stored thereon, wherein the computer program code comprises instructions for determining a representation of a hydrocarbon reservoir when run by a computer, wherein geological models constructed from a group of parameters are used to estimate static hydrocarbon volume values in the reservoir, a number of mutually independent sources of uncertainty being taken into account, at least some of the sources of uncertainty being associated with respective parameters of the group, the representation of the hydrocarbon reservoir consisting of a geological model determined to give rise to a target value of the static volume of hydrocarbons, wherein said instructions comprise instructions to execute the following steps when run by the computer:

• selecting a base case for each source of uncertainty taken into account;
• for each source of uncertainty taken into account, estimating a probability law for the static volume of hydrocarbons using models in which said source of uncertainty varies while the other sources of uncertainty conform to the respective base cases thereof;
• constructing a conversion table comprising a set of rows, each having, for each source of uncertainty taken into account, a respective quantile value corresponding to a volume value according to the probability law estimated for said source of uncertainty and further having a resultant value of the static volume of hydrocarbons calculated as a function of the volume values associated with the quantile values of the row;
• selecting a row of the conversion table having a resultant value of the static volume of hydrocarbons equal or closest to the target value of the static volume of hydrocarbons;
• and
• setting the sources of uncertainty according to the respective quantile values thereof in the selected row of the conversion table to construct the geological model forming the representation of the hydrocarbon reservoir.