Abstract: Oil exploration and production agencies as any other agency, create values by applying a combination of assets. However, assets interaction and value-creation in these companies was different. Undoubtedly, this difference is the most important common side of utilization companies and stems from assets structures features of underground resources of such companies. Generally, assets are divided into tangible and intangible ones. But there is an important asset called "underground resources" in these companies with two opposite features. First, crude oil underground resources are exhaustible. Second, a small part of proved reserves is extractable. Upon increased utilization and development of values of human, information and structural intangible assets and spending R&D costs which are from intangible and intelligent assets, more parts of underground assets are converted to extractable assets by increased recovery factor. Thus, intelligent assets of an upstream company are leading ones. This study studies this subject and also studies unit capital cost calculation mechanism by Tobin’s Q Theory. Equation for exhaustible assets may be interpreted according to the triple components of asset cost-interest opportunity cost, asset depreciation makeup cost and asset value changes cost. The first term of the obtained equation for upstream company is make-up cost of extracted crude oil (deducted from extractable reserve), the second sentence is the opportunity cost of investment interest for converting in situ oil resources to extractable reserve (increment of recovery factor) and most importantly, shows market price increment of exhaustible resource converted to extractable oil. The important point is that, regarding to scarcity rule, market value of exhaustible resource converted to extractable oil increased more rapidly than tangible assets. The obtained equation implies that optimal final cost for converting in situ unit oil to extractable reserve is equal to the market value of produced crude oil resulted due to recoverable reserve. By this rule we can obtain optimal investment rate to increase recovery factor of upstream agency. In other words, Tobin’s rule implies that for determination of optimal investment limit for excess extraction from oil and gas resources, if q<1, then investment limit must be decreased to increase recovery factor. If q>1, then investment limit must be increased to increase recovery factor. Therefore, the optimal investment limit is when q = 1.