We Claim:
1. A method of improving the production of a mature gas or oil field, said field
comprising a plurality of existing wells, said method comprising:
- providing a field simulator capable of predicting the production of said field, well by well, in function of a production scenario, the production scenario being represented by a set of data comprising production parameters of the existing wells and, location and production parameters of one or more new wells,
- determining drainage areas of said existing wells using the field simulator,
- determining locations of candidate new wells such that drainage areas of said candidate new wells, determined using the field simulator, do not overlap with the drainage areas of the existing wells,
- determining a plurality of sets of wells, each set of wells comprising the existing wells and new wells selected among the candidate new wells,
- determining, for each set of wells, the value of a gain function, which depends on the production of the field, and
selecting the set of wells from among the plurality of sets of wells that optimizes the value of the gain function.
2. The method as claimed in claim 1, comprising an heuristic step wherein candidate new wells are preselected or deselected by applying at least one heuristic rule, each set of wells of said plurality of sets of wells consisting of the existing wells and new wells selected among the preselected candidate new wells.
3. The method as claimed in claim 2. wherein said heuristic rale comprises preselecting and deselecting candidate new horizontal wells, depending on their orientation.
4. The method as claimed in claim 2, wherein said heuristic rule comprises preselecting and deselecting candidate new wells, depending on their distance with the existing wells.
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Clear Claims

5. The method as claimed in claim 2, wherein said heuristic rule comprises preselecting and deselecting candidate new wells, depending on their cumulated oil production determined by the field simulator.
6. The method as claimed in claim 1, wherein optimizing the value of a gain function comprises determining the optimum production parameters for a given set of wells by applying deterministic or non-deterministic optimization methods.
7. The method as claimed in claim 1, wherein optimizing the value of a gain function comprises determining the optimum given set of wells by applying non-deterministic optimization methods.
8. The method as claimed in claim 1, wherein optimizing the value of said gain function comprises determining a set of injectors which optimize the value of said gain function.
9. The method as claimed in claim 1, wherein at least one of the wells has a multi-layered geology, and the field simulator is capable of predicting a production of said field, well by well and by layer or groups of layers.
10. The method as claimed in claim 1, comprising the step of defining constraints to be fulfilled by the set of wells which optimizes the value of said gain function.
11. The method as claimed in claim 6, comprising the step of defining constraints to be fulfilled by said optimum production parameters.

VASUNDHARA SANKARAN
IN/PA-2093
OF K & S PARTNERS
AGENT FOR THE APPLICANT(S)
Dated this 14th day of December, 2012
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