On the feasibility of re-stimulation of shale wells

As a result of advances in horizontal comple- tions and multi-stage hydraulic fracturing, the U.S. has been able to economically develop several decades of worth of natural gas. However, a considerable concern has risen on the economic viability of shale gas development for reasons associated with the fast production declines as well as recent down-turns of natural gas prices besides rises in the costs of new technologies. Therefore, an economic analysis is required to investigate the profitability of the re- fracturing treatment of unconventional gas resources. Net present value of cash flows and internal rate of return are calculated for a range of gas prices considering 20 years of natural gas production from a typical unconventional shale gas reservoir. A systematic comparison is then accom- plished for three scenarios： （1） re-fracturing versus no re- fracturing, （2） combination of re-fracturing and drilling new wells, and （3） time-dependent re-fracturing treatment. Further, this paper incorporates the cost of re-fracturing treatment, the cost of drilling a new horizontal well, the water treatment cost, as well as the current and future price of natural gas in the model. The findings of this work would help the future re-stimulation development plans of the emerging unconventional shale gas plays.

Modelling the Iranian Petroleum Contract fiscal regime using bargaining game theory to guide contract negotiators

Based on Iran's sixth development plan,the country's oil and gas industry requires an investment of about$200 bn in the next five years to increase production.The Iranian government,to attract and motivate international oil company investment in their oil and gas fields,has presented a new type of risk service contract:the Iranian Petroleum Contract(IPC).This paper summarizes the features of the IPC and presents mathematical models of its fiscal regime for the benefit and guidance of both the National Iranian Oil Company(NIOC)and the contractors.Next,adopting bargaining game theory provides a mathematical model for reaching a win-win situation between the NIOC and the contractor.Finally,a numerical example is given and a sensitivity analysis performed to illustrate the implementation of the proposed models.The contractor and the NIOC may use these models when preparing their proposal and in the course of actual negotiations to calculate their internal rate of return,remuneration fee,and net present value for developing the fields at different conditions of their bargaining power,and derive a logical bargain to protect their best possible interests.

Biomass energy cost and feasibility of gasifier based biomass power generation system

The present research work has been carried out on biomass based on 10 kW capacity gasifier power generation system installed at College of Agricultural Engineering and Technology,Dr.Panjabrao Deshmukh Agricultural University(Dr.PDKV),Akola Maharashtra,India.The main objectives were to evaluate various costs and benefits involved in the power generation system.The costs of energy per unit were calculated for the first year of operation.The economics of gasifier based power generation system and thereby the feasibility of the system was examined by estimating per unit cost,Net Present Value(NPV),Benefit Cost Ratio(BCR),Internal Rate of Return(IRR)and payback period.The discount cash flow method was used to find out the IRR.In the present analysis,three costs viz.,installed capital cost,operation and maintenance cost,and levelised replacement cost were examined for the evaluation of the power generation per unit.Discount rate on investment in case of subsidy(Case I)and in case without subsidy(Case II)for installation cost of system was considered as 12.75%.The BCR comes in Case I for operating duration of 22 h,20 h,and 16 h are 1.24,1.18,and 1.13,respectively.Similarly for Case II BCR comes 1.44,1.38,and 2.39.The IRR comes in Case I for operating duration of 22 h,20 h,and 16 h are 26%,22%,and 19%,respectively.Similarly for Case II,IRR comes 52%,44%,and 39%for operating duration of 22 h,20 h,and 16 h,respectively.The payback period in the present analysis was worked out.The payback period for biomass based gasifier power generation system was observed to be for Case I from three to four years and for Case II it was one to two years.