Current petroleum industry practice (as reported by Beucher et. al.1 and Bratvold and Begg2 etc. AAPG 2008) adopts schemes that aim at separating risk into two main categories; subsurface risk that includes resource size, production rate, and access cost and surface risk that demonstrates total expenditure, facilities delivery, delays, performance, oil/gas revenues and costs. A recent SPE review (Bartvold el al SPE RE 2009) of decision making in the petroleum industry shows great dependence on VOI (Value of Information), to manage risk. VOI cannot stand alone as a decision making tool. There are also shortcomings in the use of Monte Carlo simulation. In this paper, we introduce an integrated approach for handling risk associated with oil and gas exploration as well as development of mature reservoirs through EOR and IOR. Test case includes a major asset in Abu Dhabi selected due to its varying reservoir settings. The proposed approach basically, integrates uncertainty elements that may create "business risk" causing "business impact". This solution methodology breaks down each risk parameter to sub‑parameters. Critical and non critical sub‑parameters are broken down to even more detailed pieces of risk components, down to the smallest fragments of risk. Thereafter, a down‑to‑top risk analysis technique is adopted to reach to target NCF (Net Cash Flow). Proposed is a tool for risk analysis modeling criteria related to exploration of oil and gas, and development of mature fields. In particular, it focuses on comprehension and inclusion and negates lumping/dropping of any risk parameter. This is not only because petroleum industry is surrounded by lots of uncertainties and therefore carries a huge risk, but also because other economies are revolving and highly dependent on this industry. In many cases, ignored risk parameters, that once thought non‑critical, turned to business disasters.