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US 10,378,348 B2Granted
Method for evaluating properties of a fluid medium
AssigneeTotal SA
InventorEmmanuel Caroli
Life of this patent
Estimating the term…
Abstract
The present invention relates to a method for determination of fluid characteristics in a well, by receiving mass ratios and a molecular ratio; converting the mass ratios into molecular ratios based on predetermined molecular weights; normalizing the converted molecular ratios with the received molecular ratio; minimizing a difference between the normalized molecular ratio and an associated member or an associated sum of members; computing an estimated molecular weight (Mw6+) function of (k+11−αΔM; and if a stabilization criteria is met, the steps are iterated with the estimated molecular weight as one of the predetermined molecular weights.
Claims8
A method for determining the fluid characteristics in a well, wherein said method comprises:
- /a/ receiving a mass ratio by Downhole Fluid Analysis (DFA) measurements, each mass ratio being associated with a set of hydrocarbon cuts, and receiving a molecular ratio, said molecular ratio being associated with a set of hydrocarbon cuts;
- /b/ converting received mass ratios into molecular ratios based on predetermined molecular weights, each predetermined molecular weights being associated with an element in the sets of hydrocarbon cuts;
- /c/ normalizing converted molecular ratios with the received molecular ratio;
- /d/ determining parameters (α,β) of a sequence defined by
- x
- n
- =
- α
-
- (
- 1
- -
- β
- n
- )
-
- x
- n
- -
- 1
- ,
- each normalized molecular ratio being associated with a member of the sequence or a sum of members of the sequence, at least a difference between said normalized molecular ratio and the associated member or the associated sum of members being minimized;
- /e/ computing an estimated molecular weight (Mw6+) function of
- (
- k
- +
- 1
- 1
- -
- α
- )
-
- Δ
-
-
- M
- ,
- where k is an integer and ΔM is a predetermined value representing a molecular weight increment between two hydrocarbon cuts;
- /f/ if a stabilization criteria is met, the steps /b/ to /f/ are iterated with the estimated molecular weight as one of the predetermined molecular weights in step /b/;
- /g/ outputting the values of the parameters determined in step /d/ to predict the concentration of hydrocarbon cuts of a rank n, n being strictly higher than 6, and
- h/ quantify properties for the hydrocarbon cuts heavier than 6 to determine at least one in situ fluid characteristic chosen among API gravity, downhole density, gas oil ratio and formation volume factor.
38 more elements
A method for determining a fluid characteristic for a plurality of elevation values (z1, z2, z3) in a well, wherein said method comprises:
- /i/ determining a plurality of values Δ by executing for each of the elevation values (z1, z2, z3) the steps of:
- /a/ receiving mass ratios by Downhole Fluid Analysis (DFA) measurements, each mass ratio being associated with a set of hydrocarbon cuts, and receiving a molecular ratio, said molecular ratio being associated with a set of hydrocarbon cuts;
- /b/ converting received mass ratios into molecular ratios based on predetermined molecular weights, each predetermined molecular weights being associated an element in the sets of hydrocarbon cuts;
- /c/ normalizing converted molecular ratios with the received molecular ratio;
- /d/ determining parameters (α,β) of a sequence defined by xn=α(1−βnxn−1, each normalized molecular ratio being associated with a member of the sequence or a sum of members of the sequence, at least a difference between said normalized molecular ratio and the associated member or the associated sum of members being minimized;
- /e/ computing an estimated molecular weight (Mw6+) function of
- (
- k
- +
- 1
- 1
- -
- α
- )
-
- Δ
-
-
- M
- ,
- where k being an integer and ΔM being a predetermined value representing a molecular weight increment between two hydrocarbon cuts;
- /f/ if a stabilization criteria is met, the steps /b/ to /f/ are iterated with the estimated molecular weight as one of the predetermined molecular weights in step /b/;
- /g/ outputting the values of the parameters determined in step /d/ to predict the concentration of a hydrocarbon cuts of rank n, n being strictly higher than 6, and
- /h/ quantify properties for the hydrocarbon cuts heavier than 6 to determine at least one in situ fluid characteristic chosen among API gravity, downhole density, gas oil ratio and formation volume factor;
- /ii/ determining a mean molecular weight increment value by computing a plurality of values
- RT
- g
-
- (
- z
- i
- -
- z
- j
- )
-
- ln
-
- (
- α
-
- (
- z
- i
- )
- α
-
- (
- z
- j
- )
- )
- ,
- zi) being an elevation value in the plurality of elevation values and α(zi) being the determined value α in step /i/ for the elevation value zi, zj being an elevation value in the plurality of elevation values different from zi and α(zj) being the determined value α in step /i/ for the elevation value zj;
- /iii/ if a stabilization criteria is met, the steps /i/ to /iii/ are iterated with the mean molecular weight increment value as ΔM in step /d/;
- /iv/ outputting the values of the parameters determined in step /i/ and the mean molecular weight increment value determined in step /ii/.
53 more elements
Dependencies are inferred from the claim text.