Development of unconventional shale gas resources involves intensive capital investment accompanying large commercial production uncertainties. Economic appraisal, bringing together multidisciplinary project data and ...Development of unconventional shale gas resources involves intensive capital investment accompanying large commercial production uncertainties. Economic appraisal, bringing together multidisciplinary project data and information and providing likely economic outcomes for various development scenarios, forms the core of business decision-making. This paper uses a discounted cash flow(DCF) model to evaluate the economic outcome of shale gas development in the Horn River Basin,northeastern British Columbia, Canada. Through numerical examples, this study demonstrates that the use of a single average decline curve for the whole shale gas play is the equivalent of the results from a random drilling process.Business decision based on a DCF model using a single decline curve could be vulnerable to drastic changes of shale gas productivity across the play region. A random drilling model takes those drastic changes in well estimated ultimate recovery(EUR) and decline rates into account in the economic appraisal, providing more information useful for business decisions. Assuming a natural gas well-head price of $4/MCF and using a 10 % discount rate, the results from this study suggest that a random drilling strategy(e.g.,one that does not regard well EURs), could lead to a negative net present value(NPV); whereas a drilling sequence that gives priority to developing those wells with larger EURs earlier in the drilling history could result in apositive NPV with various payback time and internal rate of return(IRR). Under a random drilling assumption, the breakeven price is $4.2/MCF with more than 10 years of payout time. In contrast, if the drilling order is strictly proportional to well EURs, the result is a much better economic outcome with a breakeven price below the assumed well-head price accompanied by a higher IRR.展开更多
The Environmental Protection Tax Law that took effect in 2018 gave local authorities a certain amount of discretionary power to set the local rates for environmental protection tax.The inter-provincial gradient tax ra...The Environmental Protection Tax Law that took effect in 2018 gave local authorities a certain amount of discretionary power to set the local rates for environmental protection tax.The inter-provincial gradient tax rates pattern may induce strategic relocation of enterprises,leading to unintended policy results.Combined with the data on trans-regional investment of listed companies,this paper employs the Difference-in-Difference(DID)approach to study the impact of inter-provincially different environmental tax rates on the trans-regional migration of polluting enterprises.The study shows that due to the regional differences in the tax rates,the polluting enterprises opt for the relocation strategy of"avoiding high tax rates and opting for low rates",setting up more subsidiaries in regions with relatively low tax rates.Further research demonstrates that the trans-regional migration induced by different tax rates can help reduce production costs and increase corporate profits,while dampening the corporate enthusiasm for green innovation in the short term and resulting in pollution transfer.This paper reveals the unintended policy effects that may derive from the environmental tax reform,providing concrete proof for the comprehensive evaluation and understanding of the actual policy effects of existing environmental tax reform.展开更多
Petroleum resource assessment using reservoir volumetric approach relies on porosity and oil/gas saturation characterization by laboratory tests.In liquid-rich resource plays,the pore fluids are subject to phase chang...Petroleum resource assessment using reservoir volumetric approach relies on porosity and oil/gas saturation characterization by laboratory tests.In liquid-rich resource plays,the pore fluids are subject to phase changes and mass loss when a drilled core is brought to the surface due to volume expansion and evaporation.Further,these two closely related volumetric parameters are usually estimated separately with gas saturation inferred by compositional complementary law,resulting in a distorted gas to oil ratio under the circumstances of liquid hydrocarbon loss from sample.When applied to liquid-rich shale resource play,this can lead to overall under-estimation of resource volume,distorted gas and oil ratio(GOR),and understated resource heterogeneity in the shale reservoir.This article proposes an integrated mass balance approach for resource calculation in liquid-rich shale plays.The proposed method integrates bulk rock geochemical data with production and reservoir parameters to overcome the problems associated with laboratory characterization of the volumetric parameters by restoring the gaseous and light hydrocarbon loss due to volume expansion and evaporation in the sample.The method is applied to a Duvernay production well(14-16-62-21 W5)in the Western Canada Sedimentary Basin(WCSB)to demonstrate its use in resource evaluation for a liquid-rich play.The results show that(a)by considering the phase behavior of reservoir fluids,the proposed method can be used to infer the quantity of the lost gaseous and light hydrocarbons;(b)by taking into account the lost gaseous and light hydrocarbons,the method generates an unbiased and representative resource potential;and(c)using the corrected oil and gas mass for the analyzed samples,the method produces a GOR estimate close to compositional characteristics of the produced hydrocarbons from initial production in 14-16-62-21 W5 well.展开更多
基金funded partly by the eco EII program and supported by Geoscience for New Energy Supply Program of Natural Resources Canada
文摘Development of unconventional shale gas resources involves intensive capital investment accompanying large commercial production uncertainties. Economic appraisal, bringing together multidisciplinary project data and information and providing likely economic outcomes for various development scenarios, forms the core of business decision-making. This paper uses a discounted cash flow(DCF) model to evaluate the economic outcome of shale gas development in the Horn River Basin,northeastern British Columbia, Canada. Through numerical examples, this study demonstrates that the use of a single average decline curve for the whole shale gas play is the equivalent of the results from a random drilling process.Business decision based on a DCF model using a single decline curve could be vulnerable to drastic changes of shale gas productivity across the play region. A random drilling model takes those drastic changes in well estimated ultimate recovery(EUR) and decline rates into account in the economic appraisal, providing more information useful for business decisions. Assuming a natural gas well-head price of $4/MCF and using a 10 % discount rate, the results from this study suggest that a random drilling strategy(e.g.,one that does not regard well EURs), could lead to a negative net present value(NPV); whereas a drilling sequence that gives priority to developing those wells with larger EURs earlier in the drilling history could result in apositive NPV with various payback time and internal rate of return(IRR). Under a random drilling assumption, the breakeven price is $4.2/MCF with more than 10 years of payout time. In contrast, if the drilling order is strictly proportional to well EURs, the result is a much better economic outcome with a breakeven price below the assumed well-head price accompanied by a higher IRR.
基金Major Project of the National Social Science Fund of China"Research on Local Financial System Reform in the Development of Equal Access to Basic Public Services"(18ZDA096)the Sci-Tech Innovation Program for Postgraduates of Department of Finance at the School of Economics of Xiamen University"Research on Financial Pressure and Coping Strategies of Local Governments".The authors would like to express appreciation for the valuable suggestions from anonymous reviewers and the editorial department.The authors take sole responsibility for the paper.
文摘The Environmental Protection Tax Law that took effect in 2018 gave local authorities a certain amount of discretionary power to set the local rates for environmental protection tax.The inter-provincial gradient tax rates pattern may induce strategic relocation of enterprises,leading to unintended policy results.Combined with the data on trans-regional investment of listed companies,this paper employs the Difference-in-Difference(DID)approach to study the impact of inter-provincially different environmental tax rates on the trans-regional migration of polluting enterprises.The study shows that due to the regional differences in the tax rates,the polluting enterprises opt for the relocation strategy of"avoiding high tax rates and opting for low rates",setting up more subsidiaries in regions with relatively low tax rates.Further research demonstrates that the trans-regional migration induced by different tax rates can help reduce production costs and increase corporate profits,while dampening the corporate enthusiasm for green innovation in the short term and resulting in pollution transfer.This paper reveals the unintended policy effects that may derive from the environmental tax reform,providing concrete proof for the comprehensive evaluation and understanding of the actual policy effects of existing environmental tax reform.
文摘Petroleum resource assessment using reservoir volumetric approach relies on porosity and oil/gas saturation characterization by laboratory tests.In liquid-rich resource plays,the pore fluids are subject to phase changes and mass loss when a drilled core is brought to the surface due to volume expansion and evaporation.Further,these two closely related volumetric parameters are usually estimated separately with gas saturation inferred by compositional complementary law,resulting in a distorted gas to oil ratio under the circumstances of liquid hydrocarbon loss from sample.When applied to liquid-rich shale resource play,this can lead to overall under-estimation of resource volume,distorted gas and oil ratio(GOR),and understated resource heterogeneity in the shale reservoir.This article proposes an integrated mass balance approach for resource calculation in liquid-rich shale plays.The proposed method integrates bulk rock geochemical data with production and reservoir parameters to overcome the problems associated with laboratory characterization of the volumetric parameters by restoring the gaseous and light hydrocarbon loss due to volume expansion and evaporation in the sample.The method is applied to a Duvernay production well(14-16-62-21 W5)in the Western Canada Sedimentary Basin(WCSB)to demonstrate its use in resource evaluation for a liquid-rich play.The results show that(a)by considering the phase behavior of reservoir fluids,the proposed method can be used to infer the quantity of the lost gaseous and light hydrocarbons;(b)by taking into account the lost gaseous and light hydrocarbons,the method generates an unbiased and representative resource potential;and(c)using the corrected oil and gas mass for the analyzed samples,the method produces a GOR estimate close to compositional characteristics of the produced hydrocarbons from initial production in 14-16-62-21 W5 well.
