A method and apparatus for real-time analysis of wellsite inventory activity is described. The method includes logging receipt of inventory items at a wellsite and tracking their use. In certain embodiments, the inventory may be chemical sacks mixed into drilling fluids, and their use may be tracked with an RFID scanner near the threshold of a mixing hopper. The tracking information may be used to update an inventory management database. When an item is used, real-time wellsite data may be analyzed to determine its impact on drilling performance. The efficacy of the item may thereby be determined and stored in a predictive model database. In making future wellsite drilling decisions, the predictive model database may be used to select cost-efficient performance improvement solutions. Additionally, performance information may be used to correct real-time data measured during future uses of the inventory item. Reports may be produced from the collected information, including billing reports, regulatory reports, and end-of-well reports. Information collected from various wells may assist during planning for future well-sites, including assessing inventory needs, developing a logistical plan, and bidding on projects.