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 ris...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.展开更多
Thousands of horizontal wells are drilled into the shale formations across the U.S.and hydrocarbon production is substantially increased during past years.This fact is accredited to advances obtained in hydraulic frac...Thousands of horizontal wells are drilled into the shale formations across the U.S.and hydrocarbon production is substantially increased during past years.This fact is accredited to advances obtained in hydraulic fracturing and pad drilling technologies.The contribution of shale rock surface desorption to production is widely accepted and confirmed by laboratory and field evidences.Nevertheless,the subsequent changes in porosity and permeability due to desorption combined with hydraulic fracture closures caused by increased net effective rock stress state,have not been captured in current shale modeling and simulation.Hence,it is essential to investigate the effects of induced permeability,porosity,and stress by desorption on ultimate hydrocarbon recovery.We have developed a numerical model to study the effect of changes in porosity,permeability and compaction on four major U.S.shale formations considering their Langmuir isotherm desorption behavior.These resources include;Marcellus,New Albany,Barnett and Haynesville Shales.First,we introduced a model that is a physical transport of single-phase gas flow in shale porous rock.Later,the governing equations are implemented into a one-dimensional numerical model and solved using a fully implicit solution method.It is found that the natural gas production is substantially affected by desorption-induced porosity/permeability changes and geomechancis.This paper provides valuable insights into accurate modeling of unconventional reservoirs that is more significant when an even small correction to the future production prediction can enormously contribute to the U.S.economy.展开更多
文摘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.
文摘Thousands of horizontal wells are drilled into the shale formations across the U.S.and hydrocarbon production is substantially increased during past years.This fact is accredited to advances obtained in hydraulic fracturing and pad drilling technologies.The contribution of shale rock surface desorption to production is widely accepted and confirmed by laboratory and field evidences.Nevertheless,the subsequent changes in porosity and permeability due to desorption combined with hydraulic fracture closures caused by increased net effective rock stress state,have not been captured in current shale modeling and simulation.Hence,it is essential to investigate the effects of induced permeability,porosity,and stress by desorption on ultimate hydrocarbon recovery.We have developed a numerical model to study the effect of changes in porosity,permeability and compaction on four major U.S.shale formations considering their Langmuir isotherm desorption behavior.These resources include;Marcellus,New Albany,Barnett and Haynesville Shales.First,we introduced a model that is a physical transport of single-phase gas flow in shale porous rock.Later,the governing equations are implemented into a one-dimensional numerical model and solved using a fully implicit solution method.It is found that the natural gas production is substantially affected by desorption-induced porosity/permeability changes and geomechancis.This paper provides valuable insights into accurate modeling of unconventional reservoirs that is more significant when an even small correction to the future production prediction can enormously contribute to the U.S.economy.
