A method of drilling wellbores in a reservoir, the method comprising sequentially: creating, with a computer system , an initial model of a well field having a plurality of wells , each well being associated with a spatially-dependent parameter representing a parameter which when changed at one well affects a similar parameter at other wells; dividing, with the computer system, the well field into first and second regions, the first region including a first subset of the plurality of wells and the second region including a second subset of the plurality of wells , wherein the first and second regions overlap such that at least one well is included in both the first region and the second region; solving, with the computer system, for the parameters associated with the wells in the first subset to get a first set of values while holding constant the parameters associated with the wells in the second subset, the first set of values optimizing an objective function across the well field; setting, with the computer system, the parameters associated with the wells in the first subset to the first set of values; and solving, with the computer system, for the parameters associated with the wells in the second subset to get a second set of values while holding constant the parameters associated with the wells in the first subset, the second set of values optimizing the objective function across the well field, and based on the first and second sets of values, with the computer system, selecting a position and trajectory for a plurality of physical wellbores in a reservoir; preparing equipment to construct the plurality of physical wellbores; and drilling the plurality of physical wellbores in accordance with the selected trajectory. creating, with a computer system , an initial model of a well field having a plurality of wells , each well being associated with a spatially-dependent parameter representing a parameter which when changed at one well affects a similar parameter at other wells; dividing, with the computer system, the well field into first and second regions, the first region including a first subset of the plurality of wells and the second region including a second subset of the plurality of wells , wherein the first and second regions overlap such that at least one well is included in both the first region and the second region; solving, with the computer system, for the parameters associated with the wells in the first subset to get a first set of values while holding constant the parameters associated with the wells in the second subset, the first set of values optimizing an objective function across the well field; setting, with the computer system, the parameters associated with the wells in the first subset to the first set of values; and solving, with the computer system, for the parameters associated with the wells in the second subset to get a second set of values while holding constant the parameters associated with the wells in the first subset, the second set of values optimizing the objective function across the well field, and based on the first and second sets of values, with the computer system, selecting a position and trajectory for a plurality of physical wellbores in a reservoir; preparing equipment to construct the plurality of physical wellbores; and drilling the plurality of physical wellbores in accordance with the selected trajectory. <EOS>