After the impoundment of the Three Gorges Reservoir,some huge ancient landslides were reactivated and deformed,showing typical hydrodynamic pressure landslide characteristics.The Baishuihe landslide was a typical hydr...After the impoundment of the Three Gorges Reservoir,some huge ancient landslides were reactivated and deformed,showing typical hydrodynamic pressure landslide characteristics.The Baishuihe landslide was a typical hydrodynamic pressure landslide.The management department conducted slope cutting treatments from 2018 to 2019.To evaluate the treatment effect of rear slope cutting,this study analyzed the data of the surface deformation survey and field monitoring over the past 20 years and the characteristics of the reservoir water-triggered Baishuihe landslide deformation,and calculated the seepage field,displacement field,and stability coefficient before and after landslide treatment.The results showed that the deformation of the Baishuihe landslide was primarily related to a decrease in the reservoir water level.Owing to the poor permeability of the landslide soil,the decrease in the reservoir water level produced a seepage force pointing to the outside of the landslide body,leading to the step deformation of the landslide displacement.The landslide was treated by rear slope cutting,and the“step”deformation of the landslide disappeared after treatment.The hydrodynamic pressure caused by the change in reservoir water after cutting the slope did not disappear.However,as the slope cutting greatly reduced the overall sliding force of the landslide,its stability was greatly improved.Notably,high stability can still be ensured under extreme rainfall after treatment.Slope cutting is effective for treating hydrodynamic pressure landslides.This study can provide effective technical support for the treatment of reservoir landslides.展开更多
A new numerical model for low-permeability reservoirs is developed.The model incorporates the nonlinear characteristics of oil-water two-phase flows while taking into account the initiation pressure gradient.Related n...A new numerical model for low-permeability reservoirs is developed.The model incorporates the nonlinear characteristics of oil-water two-phase flows while taking into account the initiation pressure gradient.Related numerical solutions are obtained using a finite difference method.The correctness of the method is demonstrated using a two-dimensional inhomogeneous low permeability example.Then,the differences in the cumulative oil and water production are investigated for different starting water saturations.It is shown that when the initial water saturation grows,the water content of the block continues to rise and the cumulative oil production gradually decreases.展开更多
A deep learning method for predicting oil field production at ultra-high water cut stage from the existing oil field production data was presented,and the experimental verification and application effect analysis were...A deep learning method for predicting oil field production at ultra-high water cut stage from the existing oil field production data was presented,and the experimental verification and application effect analysis were carried out.Since the traditional Fully Connected Neural Network(FCNN)is incapable of preserving the correlation of time series data,the Long Short-Term Memory(LSTM)network,which is a kind of Recurrent Neural Network(RNN),was utilized to establish a model for oil field production prediction.By this model,oil field production can be predicted from the relationship between oil production index and its influencing factors and the trend and correlation of oil production over time.Production data of a medium and high permeability sandstone oilfield in China developed by water flooding was used to predict its production at ultra-high water cut stage,and the results were compared with the results from the traditional FCNN and water drive characteristic curves.The LSTM based on deep learning has higher precision,and gives more accurate production prediction for complex time series in oil field production.The LSTM model was used to predict the monthly oil production of another two oil fields.The prediction results are good,which verifies the versatility of the method.展开更多
The natural gas pipeline from Platform QKI8-1 in the southwest of Bohai Bay to the onshore processing facility is a subsea wet gas pipeline exposed to high pressure and low temperature for a long distance. Blockages i...The natural gas pipeline from Platform QKI8-1 in the southwest of Bohai Bay to the onshore processing facility is a subsea wet gas pipeline exposed to high pressure and low temperature for a long distance. Blockages in the pipeline occur occasionally. To maintain the natural gas flow in the pipeline, we proposed a method for analyzing blockages and ascribed them to the hydrate formation and agglomeration. A new high-pressure flow loop was developed to investigate hydrate plug formation and hydrate particle size, using a mixture of diesel oil, water, and natural gas as experimental fluids. The influences of pressure and initial flow rate were also studied. Experimental results indicated that when the flow rate was below 850 kg/h, gas hydrates would form and then plug the pipeline, even at a low water content （10%） of a water/oil emulsion. Furthermore, some practical suggestions were made for daily management of the subsea pipeline.展开更多
The worldwide increase in energy demand necessitates the development and optimization of marginal oil fields for sustenance.In this regard,effective and economic production of fluids are heavily relied upon the artifi...The worldwide increase in energy demand necessitates the development and optimization of marginal oil fields for sustenance.In this regard,effective and economic production of fluids are heavily relied upon the artificial lift techniques as the reservoir's natural energy may not be able to deliver the fluids to the surface.Gas lift is a widely practised and successful method that is suitable for rejuvenating the oil production from such fields.In this study,the influence of critical parameters like water cut,wellhead pressure(WHP)and gas-lift gas injection rate on the output from a gas lifted well was analysed.A significant reduction in the oil production was observed with the increase in water cut.For a fixed gas injection rate of 1 Mmscf/day,the production decreased by 26.90%when the water cut increased from 15%to 30%and further by 50.80%when the water cut reached 45%.An increase in the gas injection rate from 1 Mmscf/day to 8 Mmscf/day resulted in an increase in the production rate by 29.21%,40.48%and 56.56%for 15%,30%,and 45%water cut conditions,respectively.It was observed that there is a drop in the oil rate with the increase in WHP for a constant gas injection rate.An increase in the WHP from 100 psi to 300 psi resulted in a drop in the oil production rate by 11.01%,11.78%and 12.74%for 15%,30%and 45%water cut conditions,respectively.The study sheds light on the significance of optimizing the critical parameters to maximize the production from a well,with severely affected productivity,using a continuous gas lift system.展开更多
基金supported by the National Natural Science Foundation of China(No.U21A2031)Key R&D Program of Hubei Province(No.2022BAA047)+3 种基金China Postdoctoral Science Foundation(No.2021M701969)Open Fund of Key Laboratory of Geological Hazards on Three Gorges Reservoir Area(2022KDZ19)the Open Fund of Badong National Observation and Research Station of Geohazards(No.BNORSG-202207No.BNORSG-202304)。
文摘After the impoundment of the Three Gorges Reservoir,some huge ancient landslides were reactivated and deformed,showing typical hydrodynamic pressure landslide characteristics.The Baishuihe landslide was a typical hydrodynamic pressure landslide.The management department conducted slope cutting treatments from 2018 to 2019.To evaluate the treatment effect of rear slope cutting,this study analyzed the data of the surface deformation survey and field monitoring over the past 20 years and the characteristics of the reservoir water-triggered Baishuihe landslide deformation,and calculated the seepage field,displacement field,and stability coefficient before and after landslide treatment.The results showed that the deformation of the Baishuihe landslide was primarily related to a decrease in the reservoir water level.Owing to the poor permeability of the landslide soil,the decrease in the reservoir water level produced a seepage force pointing to the outside of the landslide body,leading to the step deformation of the landslide displacement.The landslide was treated by rear slope cutting,and the“step”deformation of the landslide disappeared after treatment.The hydrodynamic pressure caused by the change in reservoir water after cutting the slope did not disappear.However,as the slope cutting greatly reduced the overall sliding force of the landslide,its stability was greatly improved.Notably,high stability can still be ensured under extreme rainfall after treatment.Slope cutting is effective for treating hydrodynamic pressure landslides.This study can provide effective technical support for the treatment of reservoir landslides.
文摘A new numerical model for low-permeability reservoirs is developed.The model incorporates the nonlinear characteristics of oil-water two-phase flows while taking into account the initiation pressure gradient.Related numerical solutions are obtained using a finite difference method.The correctness of the method is demonstrated using a two-dimensional inhomogeneous low permeability example.Then,the differences in the cumulative oil and water production are investigated for different starting water saturations.It is shown that when the initial water saturation grows,the water content of the block continues to rise and the cumulative oil production gradually decreases.
基金Supported by China National Science and Technology Major Project(2016ZX05016-006)
文摘A deep learning method for predicting oil field production at ultra-high water cut stage from the existing oil field production data was presented,and the experimental verification and application effect analysis were carried out.Since the traditional Fully Connected Neural Network(FCNN)is incapable of preserving the correlation of time series data,the Long Short-Term Memory(LSTM)network,which is a kind of Recurrent Neural Network(RNN),was utilized to establish a model for oil field production prediction.By this model,oil field production can be predicted from the relationship between oil production index and its influencing factors and the trend and correlation of oil production over time.Production data of a medium and high permeability sandstone oilfield in China developed by water flooding was used to predict its production at ultra-high water cut stage,and the results were compared with the results from the traditional FCNN and water drive characteristic curves.The LSTM based on deep learning has higher precision,and gives more accurate production prediction for complex time series in oil field production.The LSTM model was used to predict the monthly oil production of another two oil fields.The prediction results are good,which verifies the versatility of the method.
基金support from Subtopics of National Science and Technology Major Project(2011ZX05026-004-03)the National Natural Science Foundation of China (51104167)
文摘The natural gas pipeline from Platform QKI8-1 in the southwest of Bohai Bay to the onshore processing facility is a subsea wet gas pipeline exposed to high pressure and low temperature for a long distance. Blockages in the pipeline occur occasionally. To maintain the natural gas flow in the pipeline, we proposed a method for analyzing blockages and ascribed them to the hydrate formation and agglomeration. A new high-pressure flow loop was developed to investigate hydrate plug formation and hydrate particle size, using a mixture of diesel oil, water, and natural gas as experimental fluids. The influences of pressure and initial flow rate were also studied. Experimental results indicated that when the flow rate was below 850 kg/h, gas hydrates would form and then plug the pipeline, even at a low water content （10%） of a water/oil emulsion. Furthermore, some practical suggestions were made for daily management of the subsea pipeline.
文摘The worldwide increase in energy demand necessitates the development and optimization of marginal oil fields for sustenance.In this regard,effective and economic production of fluids are heavily relied upon the artificial lift techniques as the reservoir's natural energy may not be able to deliver the fluids to the surface.Gas lift is a widely practised and successful method that is suitable for rejuvenating the oil production from such fields.In this study,the influence of critical parameters like water cut,wellhead pressure(WHP)and gas-lift gas injection rate on the output from a gas lifted well was analysed.A significant reduction in the oil production was observed with the increase in water cut.For a fixed gas injection rate of 1 Mmscf/day,the production decreased by 26.90%when the water cut increased from 15%to 30%and further by 50.80%when the water cut reached 45%.An increase in the gas injection rate from 1 Mmscf/day to 8 Mmscf/day resulted in an increase in the production rate by 29.21%,40.48%and 56.56%for 15%,30%,and 45%water cut conditions,respectively.It was observed that there is a drop in the oil rate with the increase in WHP for a constant gas injection rate.An increase in the WHP from 100 psi to 300 psi resulted in a drop in the oil production rate by 11.01%,11.78%and 12.74%for 15%,30%and 45%water cut conditions,respectively.The study sheds light on the significance of optimizing the critical parameters to maximize the production from a well,with severely affected productivity,using a continuous gas lift system.
