18. The data storage device of claim 16 , wherein the reservoir simulation is performed in a cluster computer formed of at least one master node and a plurality of processor nodes, with each processor node processing data regarding a portion of the reservoir, and wherein the modify data structure further identifies an array of reservoir data blocks in the model to be modified and each node has a global index of the identified array, and further including the instructions causing the nodes to each identify the grid blocks in the global index allocated to them.
16. A data storage device having stored in a computer readable medium nontransitory computer operable instructions for causing a data processing system in history matching the results of computer implemented reservoir simulation with field reservoir production data to conform the reservoir simulation with the field production data, the data processing system modifying input data regarding the reservoir to more satisfactorily match the reservoir to the field production data based on specified modify instructions regarding simulator input data about the reservoir, the data storage device containing instructions for causing the data processing system to perform the steps of: converting the modify instructions into a computer recognizable token; parsing the computer recognizable token according to a grammar to form a modify data structure; determining in the computer if the modify data structure identifies a reservoir variable, and if so, finding a pointer in computer memory to the variable; and determining in the computer if the modify data structure identifies an operator, and if so, performing the operation according to the identified operator data to modify the simulator input data.