Reasonable field acquisition geometry can not only guide seismic exploration to obtain sufficient geological information of target body,but also reduce acquisition cost to the maximum.In this study,building on convent...Reasonable field acquisition geometry can not only guide seismic exploration to obtain sufficient geological information of target body,but also reduce acquisition cost to the maximum.In this study,building on conventional ray-based geometry design methods,we incorporate imaging results as a constraint to optimize the geometry design and evaluate its effectiveness.Firstly,the geological model of the target layer is established based on the geological data of the study area and surface seismic data combined with exploration tasks.Then,the ray-tracing method is employed to simulate and assess the proposed geometry design,verifying whether its parameters meet the exploration requirements.Finally,the imaging effect of the designed geometry on the target layer is tested by the cross-well seismic reverse time migration method.This methodology was applied to design the cross-well seismic acquisition geometry for offshore deviated wells in the X Oilfield.The simulation results demonstrate that the imaging-driven geometry design approach effectively guides field operations,enhances the imaging quality of the target layer,and reduces acquisition costs.展开更多
In this work, the unified fracture design （UFD） is extended for the first time to the fractured horizontal wells in heterogeneous closed box-shaped tight gas reservoirs. Utilizing the direct boundary element method ...In this work, the unified fracture design （UFD） is extended for the first time to the fractured horizontal wells in heterogeneous closed box-shaped tight gas reservoirs. Utilizing the direct boundary element method and influence function, the dimensionless fracture productivity index is obtained and expressed in the function of proppant volume and fracture geometry at the pseu- do-steady state. With the iterative method, the effectively propped permeability, kfe, is corrected using the i^-situ Reynolds number, NRe. The goal of this paper is to present a new UFD extension to design the proppant volume and the optimal fracture geometry. The results show that there exists an optimal proppant volume for a certain reservoir. The small aspect ratio （yJXe） and high permeability reservoirs need short and wide fractures to diminish the non-Darcy effect. On the contrary, long and narrow fractures are required for the large aspect ratio and low permeability reservoirs. A small proppant volame is prone to creating long fractures, while a relatively large proppant volume creates wide fractures. The new extension can be used to evaluate the previous fracture parameters and design the following fracture parameters of the fractured horizontal well in heterogeneous tight gas reservoirs, with the non-Darcy effect taken into account.展开更多
It is a commonly asked question:how big should the longwall shields be? The answer is a key aspect of a longwall mining feasibility study when the consequences of inadequately rated shields are considered.This paper a...It is a commonly asked question:how big should the longwall shields be? The answer is a key aspect of a longwall mining feasibility study when the consequences of inadequately rated shields are considered.This paper addresses this question based on the measured nature of the loading environment in which shields are required to operate,the various geological and geometrical controls of that environment and the various links between their load rating,a range of other relevant shield design factors and the loss event they are required to prevent a major roof collapse on the longwall face.The paper concludes that despite the tremendous advances that have been made in shield design and load rating over the past50 years,the same drivers that caused longwall miners of the past to seek improved roof control on the longwall face via the use of ever-higher rated shields,are still as relevant today.However at the current time,the limits of the largest available longwall shields have yet to be tested,therefore industry focus for the foreseeable future should possibly be in achieving the maximum level of roof control on the face via their optimum operational use rather than considering further shield rating increases and incurring the inevitable downsides in terms of capital cost and shield weight.展开更多
Seismic exploration in the mountainous areas of western Chinese is extremely difficult because of the complexity of the surface and subsurface, which results in shooting difficulties, seismic data with low signal-to-n...Seismic exploration in the mountainous areas of western Chinese is extremely difficult because of the complexity of the surface and subsurface, which results in shooting difficulties, seismic data with low signal-to-noise ratio, and strong interference. The complexity of the subsurface structure leads to strong scattering of the refl ection points; thus, the curved-line acquisition method has been used. However, the actual subsurface structural characteristics have been rarely considered. We propose a design method for irregular acquisition based on common refl ection points（CRP） to avoid difficult-to-shoot areas, while considering the structural characteristics and CRP positions and optimizing the surfacereceiving line position. We arrange the positions of the receiving points to ensure as little dispersion of subsurface CRP as possible to improve the signal-to-noise ratio of the seismic data. We verify the applicability of the method using actual data from a site in Sichuan Basin. The proposed method apparently solves the problem of seismic data acquisition and facilitates seismic exploration in structurally complex areas.展开更多
The earth surface in the Sichuan Basin and its periphery is geologically complex,which causes low signal-to-noise ratio of seismic data,poor imaging quality of seismic profiles and great difficulty in data acquisition...The earth surface in the Sichuan Basin and its periphery is geologically complex,which causes low signal-to-noise ratio of seismic data,poor imaging quality of seismic profiles and great difficulty in data acquisition.In order to ensure high-quality operation of the seismic survey project in the complex surface of the Sichuan Basin,researchers have been working continuously to solve the bottleneck problems in the seismic acquisition technology for complex surface in recent years.In addition,the upgrading of acquisition technology and operation capacity is promoted effectively by means of technical innovation,and a series of key technologies for seismic acquisition are developed.And the following application results of this series of technologies are obtained.First,the optimization design technology of the geometry based on wave equation forward modeling and actual data,combined with prestack migration imaging can show the influence of different acquisition schemes on the prestack imaging effect of complex targets more directly,which makes the seismic acquisition scheme more economic and effective.Second,by extracting landform risks and surface obstacle information intelligently,combined with field fine reconnaissance,landform risk identification and hierarchical evaluation and indoors intelligent optimization of well-shot physical point deployment are conducted,and thus the GISt intelligent deployment technology of shot point in complex surface is formed,which effectively reduces the risks of operation.Third,the cavity excitation technology which reduces the initial pressure of explosive pulse and extends the explosive action time of explosives can increase the conversion rate of rock excitation energy into effective elastic wave energy and the reflected energy and improve the quality of seismic single shot data.Fourth,combination of the automatic evaluation technology for field seismic data acquired in mountainous regions and the KL-GMLiveQC1.0 software can improve the evaluation efficiency,reduce the evaluation cost and ensure the high-quality acquisition of seismic data in complex surface.In conclusion,this series of key seismic acquisition technologies greatly improve the signal-to-noise ratio and resolution of seismic data,lay a foundation for fine reservoir prediction,and ensure the continuous important breakthrough of three-dimensional natural gas exploration and development in the gas fields of marine carbonate rock,shale gas,volcanic rock and shallow tight sandstone gas in the Sichuan Basin.展开更多
基金funded by the Young Scientists Fund of the National Natural Science Foundation of China(42304135)the scientific research project of Gansu Coal Geology Bureau(2023-07).
文摘Reasonable field acquisition geometry can not only guide seismic exploration to obtain sufficient geological information of target body,but also reduce acquisition cost to the maximum.In this study,building on conventional ray-based geometry design methods,we incorporate imaging results as a constraint to optimize the geometry design and evaluate its effectiveness.Firstly,the geological model of the target layer is established based on the geological data of the study area and surface seismic data combined with exploration tasks.Then,the ray-tracing method is employed to simulate and assess the proposed geometry design,verifying whether its parameters meet the exploration requirements.Finally,the imaging effect of the designed geometry on the target layer is tested by the cross-well seismic reverse time migration method.This methodology was applied to design the cross-well seismic acquisition geometry for offshore deviated wells in the X Oilfield.The simulation results demonstrate that the imaging-driven geometry design approach effectively guides field operations,enhances the imaging quality of the target layer,and reduces acquisition costs.
基金supported by the National Natural Science Foundation of China(Grant Nos.5152540451504203&51374178)+2 种基金Open Fund(Grant No.PLN1515)of State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation(Southwest Petroleum University)a special fund from China’s central government for the development of local colleges and universities-the National First-level Discipline in the Oil and Gas Engineering Project(Grant No.20150727)Scientific Research Starting Project of Southwest Petroleum University(Grant No.2014QHZ004)
文摘In this work, the unified fracture design （UFD） is extended for the first time to the fractured horizontal wells in heterogeneous closed box-shaped tight gas reservoirs. Utilizing the direct boundary element method and influence function, the dimensionless fracture productivity index is obtained and expressed in the function of proppant volume and fracture geometry at the pseu- do-steady state. With the iterative method, the effectively propped permeability, kfe, is corrected using the i^-situ Reynolds number, NRe. The goal of this paper is to present a new UFD extension to design the proppant volume and the optimal fracture geometry. The results show that there exists an optimal proppant volume for a certain reservoir. The small aspect ratio （yJXe） and high permeability reservoirs need short and wide fractures to diminish the non-Darcy effect. On the contrary, long and narrow fractures are required for the large aspect ratio and low permeability reservoirs. A small proppant volame is prone to creating long fractures, while a relatively large proppant volume creates wide fractures. The new extension can be used to evaluate the previous fracture parameters and design the following fracture parameters of the fractured horizontal well in heterogeneous tight gas reservoirs, with the non-Darcy effect taken into account.
文摘It is a commonly asked question:how big should the longwall shields be? The answer is a key aspect of a longwall mining feasibility study when the consequences of inadequately rated shields are considered.This paper addresses this question based on the measured nature of the loading environment in which shields are required to operate,the various geological and geometrical controls of that environment and the various links between their load rating,a range of other relevant shield design factors and the loss event they are required to prevent a major roof collapse on the longwall face.The paper concludes that despite the tremendous advances that have been made in shield design and load rating over the past50 years,the same drivers that caused longwall miners of the past to seek improved roof control on the longwall face via the use of ever-higher rated shields,are still as relevant today.However at the current time,the limits of the largest available longwall shields have yet to be tested,therefore industry focus for the foreseeable future should possibly be in achieving the maximum level of roof control on the face via their optimum operational use rather than considering further shield rating increases and incurring the inevitable downsides in terms of capital cost and shield weight.
基金funded by The National Natural Science Foundation of China(No.41304115)Sichuan Province innovative team of natural gas geology Construction Program(No.13TD0024)Fund for middle-aged core teachers of SWPU
文摘Seismic exploration in the mountainous areas of western Chinese is extremely difficult because of the complexity of the surface and subsurface, which results in shooting difficulties, seismic data with low signal-to-noise ratio, and strong interference. The complexity of the subsurface structure leads to strong scattering of the refl ection points; thus, the curved-line acquisition method has been used. However, the actual subsurface structural characteristics have been rarely considered. We propose a design method for irregular acquisition based on common refl ection points（CRP） to avoid difficult-to-shoot areas, while considering the structural characteristics and CRP positions and optimizing the surfacereceiving line position. We arrange the positions of the receiving points to ensure as little dispersion of subsurface CRP as possible to improve the signal-to-noise ratio of the seismic data. We verify the applicability of the method using actual data from a site in Sichuan Basin. The proposed method apparently solves the problem of seismic data acquisition and facilitates seismic exploration in structurally complex areas.
基金Project supported by Project 4-“Research and Application of Key Geophysical Technologies of Carbonate Rocks in Sichuan Basin”(No.:2016E-06-04)under the Major Science and Technology Special Project of PetroChina Company Limited“Research and Application of Key Technologies for Natural Gas Production of 30 Billion Cubic Meters in Southwest Oil and Gas Field”.
文摘The earth surface in the Sichuan Basin and its periphery is geologically complex,which causes low signal-to-noise ratio of seismic data,poor imaging quality of seismic profiles and great difficulty in data acquisition.In order to ensure high-quality operation of the seismic survey project in the complex surface of the Sichuan Basin,researchers have been working continuously to solve the bottleneck problems in the seismic acquisition technology for complex surface in recent years.In addition,the upgrading of acquisition technology and operation capacity is promoted effectively by means of technical innovation,and a series of key technologies for seismic acquisition are developed.And the following application results of this series of technologies are obtained.First,the optimization design technology of the geometry based on wave equation forward modeling and actual data,combined with prestack migration imaging can show the influence of different acquisition schemes on the prestack imaging effect of complex targets more directly,which makes the seismic acquisition scheme more economic and effective.Second,by extracting landform risks and surface obstacle information intelligently,combined with field fine reconnaissance,landform risk identification and hierarchical evaluation and indoors intelligent optimization of well-shot physical point deployment are conducted,and thus the GISt intelligent deployment technology of shot point in complex surface is formed,which effectively reduces the risks of operation.Third,the cavity excitation technology which reduces the initial pressure of explosive pulse and extends the explosive action time of explosives can increase the conversion rate of rock excitation energy into effective elastic wave energy and the reflected energy and improve the quality of seismic single shot data.Fourth,combination of the automatic evaluation technology for field seismic data acquired in mountainous regions and the KL-GMLiveQC1.0 software can improve the evaluation efficiency,reduce the evaluation cost and ensure the high-quality acquisition of seismic data in complex surface.In conclusion,this series of key seismic acquisition technologies greatly improve the signal-to-noise ratio and resolution of seismic data,lay a foundation for fine reservoir prediction,and ensure the continuous important breakthrough of three-dimensional natural gas exploration and development in the gas fields of marine carbonate rock,shale gas,volcanic rock and shallow tight sandstone gas in the Sichuan Basin.
