1. A system for analyzing an oilfield having at least one wellsite, each at least one wellsite having a wellbore penetrating a subterranean formation for extracting fluid from an underground reservoir therein, comprising: a data collection means for obtaining source data having a plurality of data elements of heterogeneous data types; memory for storing the source data; a functional method configured to perform a function on a dataset of a dataset type to obtain a processed dataset; and a client code configured to process the dataset comprising: an object instantiation code configured to use a dataset wrapper class to create the dataset with the dataset type from the source data; and a functional method invocation code configured to call the functional method with the dataset.