Transient rate decline curve analysis for constant pressure production is presented in this pa- per for a naturally fractured reservoir. This approach is based on exponential and constant bottom-hole pressure solution...Transient rate decline curve analysis for constant pressure production is presented in this pa- per for a naturally fractured reservoir. This approach is based on exponential and constant bottom-hole pressure solution. Based on this method, when In （flow rate） is plotted versus time, two straight lines are ob- tained which can be used for estimating different parameters of a naturally fractured reservoir. Parameters such as storage capacity ratio （co）, reservoir drainage area （A）, reservoir shape factor （CA）, fracture per- meability （ky）, interporosity flow parameter （,~） and the other parameters can be determined by this ap- proach. The equations are based on a model originally presented by Warren and Root and extended by Da Prat et al. and Mavor and Cinco-Ley. The proposed method has been developed to be used for naturally fractured reservoirs with different geometries. This method does not involve the use of any chart and by us- ing the pseudo steady state flow regime, the influence of wellbore storage on the value of the parameters ob- tained from this technique is negligible. In this technique, all the parameters can be obtained directly while in conventional approaches like type curve matching method, parameters such as co and g should be ob- tained by other methods like build-up test analysis and this is one of the most important advantages of this method that could save time during reservoir analyses. Different simulated and field examples were used for testing the proposed technique. Comparison between the obtained results by this approach and the results of type curve matching method shows a high performance of decline curves in well testing.展开更多
The shale revolution has turned the United States from an oil importer into an oil exporter.The success of shale oil production in the U.S.has inspired many countries,including China,to begin the exploitation and deve...The shale revolution has turned the United States from an oil importer into an oil exporter.The success of shale oil production in the U.S.has inspired many countries,including China,to begin the exploitation and development of shale oil resources.In this study,the production curves of over 30,000 shale oil wells in the Bakken,Eagle Ford(EF)and Permian are systematically analyzed to provide reference and guidance for future shale oil development.To find out the most suitable decline curve models for shale oil wells,fifteen models and a new fitting method are tested on wells with production history over 6 years.Interestingly,all basins show similar results despite of their varieties in geological conditions:stretched exponential production decline(SEPD)+Arps model provides most accurate prediction of estimated ultimate recovery(EUR)for wells with over 2 years'production,while the Arps model can be used before the two years'switch point.With the EUR calculated by decline curve analysis,we further construct simple regression models for different basins to predict the EUR quickly and early.This work helps us better understand the production of shale oil wells,as well as provide important suggestions for the choices of models for shale oil production prediction.展开更多
This manuscript introduces a new decline curve analysis(DCA) technique to analyze and predict the potentials of hydraulically fractured unconventional resources.The new approach relies on the ratenormalized flow rate ...This manuscript introduces a new decline curve analysis(DCA) technique to analyze and predict the potentials of hydraulically fractured unconventional resources.The new approach relies on the ratenormalized flow rate derivative(RNFD) concept.It uses the significant constant behavior of the RNFD that identifies the power-law type flow regime models of fractured reservoirs.This technique merges the RNFD with a new numerical model for the flow rate derivative(flow rate noise-reducing derivative model).The concept of the RNFD [1/q(txq')] is developed based on the power-law type analytical models of the flow regimes that can be characterized from the production history of gas or oil-producing wells.The production rate,cumulative production,and the calculated RNFDs from the production history are used for this purpose.The constant RNFD values and the flow rate derivative's numerical model can be used to simulate the production history or predict future performance.The impact of the skin factor is introduced to the approach by developing new RNFD models that could replace the constant pattern of RNFD when this impact does not exist.For a severe condition of skin factor,the RNFD shows a linear relationship with time instead of the constant value.The proposed approach gives an excellent match with the production history of the case studies examined in this study.The transition between flow regimes does not impact the application of the RNFD,i.e.,the calculations move very smoothly throughout the flow regime.The novelty of the proposed technique is represented by introducing an approach for the DCA that considers the observed flow regimes during the production history and the impact of the skin factor.The approach proposes new numerical flow rate and cumulative production models to predict future performance as well as new models for estimating the impact of skin factors on production history,especially for early time flow regimes.展开更多
文摘Transient rate decline curve analysis for constant pressure production is presented in this pa- per for a naturally fractured reservoir. This approach is based on exponential and constant bottom-hole pressure solution. Based on this method, when In （flow rate） is plotted versus time, two straight lines are ob- tained which can be used for estimating different parameters of a naturally fractured reservoir. Parameters such as storage capacity ratio （co）, reservoir drainage area （A）, reservoir shape factor （CA）, fracture per- meability （ky）, interporosity flow parameter （,~） and the other parameters can be determined by this ap- proach. The equations are based on a model originally presented by Warren and Root and extended by Da Prat et al. and Mavor and Cinco-Ley. The proposed method has been developed to be used for naturally fractured reservoirs with different geometries. This method does not involve the use of any chart and by us- ing the pseudo steady state flow regime, the influence of wellbore storage on the value of the parameters ob- tained from this technique is negligible. In this technique, all the parameters can be obtained directly while in conventional approaches like type curve matching method, parameters such as co and g should be ob- tained by other methods like build-up test analysis and this is one of the most important advantages of this method that could save time during reservoir analyses. Different simulated and field examples were used for testing the proposed technique. Comparison between the obtained results by this approach and the results of type curve matching method shows a high performance of decline curves in well testing.
基金funded by the National Natural Science Foundation of China(Grant No.52374043)the Key Program of National Natural Science Foundation of China(Grant No.52234003)。
文摘The shale revolution has turned the United States from an oil importer into an oil exporter.The success of shale oil production in the U.S.has inspired many countries,including China,to begin the exploitation and development of shale oil resources.In this study,the production curves of over 30,000 shale oil wells in the Bakken,Eagle Ford(EF)and Permian are systematically analyzed to provide reference and guidance for future shale oil development.To find out the most suitable decline curve models for shale oil wells,fifteen models and a new fitting method are tested on wells with production history over 6 years.Interestingly,all basins show similar results despite of their varieties in geological conditions:stretched exponential production decline(SEPD)+Arps model provides most accurate prediction of estimated ultimate recovery(EUR)for wells with over 2 years'production,while the Arps model can be used before the two years'switch point.With the EUR calculated by decline curve analysis,we further construct simple regression models for different basins to predict the EUR quickly and early.This work helps us better understand the production of shale oil wells,as well as provide important suggestions for the choices of models for shale oil production prediction.
文摘This manuscript introduces a new decline curve analysis(DCA) technique to analyze and predict the potentials of hydraulically fractured unconventional resources.The new approach relies on the ratenormalized flow rate derivative(RNFD) concept.It uses the significant constant behavior of the RNFD that identifies the power-law type flow regime models of fractured reservoirs.This technique merges the RNFD with a new numerical model for the flow rate derivative(flow rate noise-reducing derivative model).The concept of the RNFD [1/q(txq')] is developed based on the power-law type analytical models of the flow regimes that can be characterized from the production history of gas or oil-producing wells.The production rate,cumulative production,and the calculated RNFDs from the production history are used for this purpose.The constant RNFD values and the flow rate derivative's numerical model can be used to simulate the production history or predict future performance.The impact of the skin factor is introduced to the approach by developing new RNFD models that could replace the constant pattern of RNFD when this impact does not exist.For a severe condition of skin factor,the RNFD shows a linear relationship with time instead of the constant value.The proposed approach gives an excellent match with the production history of the case studies examined in this study.The transition between flow regimes does not impact the application of the RNFD,i.e.,the calculations move very smoothly throughout the flow regime.The novelty of the proposed technique is represented by introducing an approach for the DCA that considers the observed flow regimes during the production history and the impact of the skin factor.The approach proposes new numerical flow rate and cumulative production models to predict future performance as well as new models for estimating the impact of skin factors on production history,especially for early time flow regimes.
