To accurately reconstruct the tomographic gamma scanning(TGS)transmission measurement image,this study optimized the transmission reconstruction equation based on the actual situation of TGS transmission measurement.U...To accurately reconstruct the tomographic gamma scanning(TGS)transmission measurement image,this study optimized the transmission reconstruction equation based on the actual situation of TGS transmission measurement.Using the transmission reconstruction equation and the Monte Carlo program Geant4,an innovative virtual trajectory length model was constructed.This model integrated the solving process for the trajectory length and detection efficiency within the same model.To mitigate the influence of the angular distribution ofγ-rays emitted by the transmitted source at the detector,the transport processes of numerous particles traversing a virtual nuclear waste barrel with a density of zero were simulated.Consequently,a certain amount of information was captured at each step of particle transport.Simultaneously,the model addressed the nonuniform detection efficiency of the detector end face by considering whether the energy deposition of particles in the detector equaled their initial energy.Two models were established to validate the accuracy and reliability of the virtual trajectory length model.Model 1 was a simplified nuclear waste barrel,whereas Model 2 closely resembled the actual structure of a nuclear waste barrel.The results indicated that the proposed virtual trajectory length model significantly enhanced the precision of the trajectory length determination,substantially increasing the quality of the reconstructed images.For example,the reconstructed images of Model 2 using the“point-to-point”and average trajectory models revealed a signalto-noise ratio increase of 375.0%and 112.7%,respectively.Thus,the virtual trajectory length model proposed in this study holds paramount significance for the precise reconstruction of transmission images.Moreover,it can provide support for the accurate detection of radioactive activity in nuclear waste barrels.展开更多
In the design of a shale-gas cluster horizontal well,it is necessary to consider the bypass of the fracturing influence domains of existing wells and the interference between fracturing influence domains when the well...In the design of a shale-gas cluster horizontal well,it is necessary to consider the bypass of the fracturing influence domains of existing wells and the interference between fracturing influence domains when the wellbore trajectories of infill adjustment wells in the fracturing areas are designed.In order to quickly evaluate the rationality of the design scheme of fracturing wellbore trajectory in an infill adjustment well,this paper adopted the vector algebra method to build a geometric model of the obstacles in the shale gas fracturing area.In this geometric model,the influence domains of hydraulic fractures are taken into account.Then,based on this geometric model,the optimization design model of bypass trajectory in the shale gas fracturing area was established by taking the minimization of total trajectory length and trajectory potential energy as the optimization objective and the anti-collision between trajectories as the constraint.Besides,the geometric check method to judge if there is any interference between fracturing influence domains was provided.Finally,the established optimization design model was verified based on the actual drilling data of Fuling Shale Gas Field in the Sichuan Basin.And the following research results were obtained.First,the obstacle sizes in fracturing areas will be seriously underestimated if the fracturing influence domains are neglected.Second,if the fracturing influence domains are neglected,the designed bypass trajectory can bypass the wellbore trajectories of old wells,but may intersect the fracturing influence domains of existing wells,thus inducing drilling accidents.In conclusion,the proposed optimization design model of bypass trajectory in the shale gas fracturing area can satisfy the constraint of anti-collision and bypass and achieve the optimization objective of minimizing total trajectory length and trajectory potential energy,and the corresponding design calculation avoids complex calculation and check.展开更多
基金supported by The Youth Science Foundation of Sichuan Province(Nos.2022NSFSC1230,2022NSFSC1231,and 23NSFSC5321)the Science and Technology Innovation Seedling Project of Sichuan Province(No.MZGC20230080)+2 种基金the General project of national Natural Science Foundation of China(No.12075039)the Youth Science Foundation of China(No.12105030)the Key project of the National Natural Science Foundation of China(No.U19A2086)。
文摘To accurately reconstruct the tomographic gamma scanning(TGS)transmission measurement image,this study optimized the transmission reconstruction equation based on the actual situation of TGS transmission measurement.Using the transmission reconstruction equation and the Monte Carlo program Geant4,an innovative virtual trajectory length model was constructed.This model integrated the solving process for the trajectory length and detection efficiency within the same model.To mitigate the influence of the angular distribution ofγ-rays emitted by the transmitted source at the detector,the transport processes of numerous particles traversing a virtual nuclear waste barrel with a density of zero were simulated.Consequently,a certain amount of information was captured at each step of particle transport.Simultaneously,the model addressed the nonuniform detection efficiency of the detector end face by considering whether the energy deposition of particles in the detector equaled their initial energy.Two models were established to validate the accuracy and reliability of the virtual trajectory length model.Model 1 was a simplified nuclear waste barrel,whereas Model 2 closely resembled the actual structure of a nuclear waste barrel.The results indicated that the proposed virtual trajectory length model significantly enhanced the precision of the trajectory length determination,substantially increasing the quality of the reconstructed images.For example,the reconstructed images of Model 2 using the“point-to-point”and average trajectory models revealed a signalto-noise ratio increase of 375.0%and 112.7%,respectively.Thus,the virtual trajectory length model proposed in this study holds paramount significance for the precise reconstruction of transmission images.Moreover,it can provide support for the accurate detection of radioactive activity in nuclear waste barrels.
文摘In the design of a shale-gas cluster horizontal well,it is necessary to consider the bypass of the fracturing influence domains of existing wells and the interference between fracturing influence domains when the wellbore trajectories of infill adjustment wells in the fracturing areas are designed.In order to quickly evaluate the rationality of the design scheme of fracturing wellbore trajectory in an infill adjustment well,this paper adopted the vector algebra method to build a geometric model of the obstacles in the shale gas fracturing area.In this geometric model,the influence domains of hydraulic fractures are taken into account.Then,based on this geometric model,the optimization design model of bypass trajectory in the shale gas fracturing area was established by taking the minimization of total trajectory length and trajectory potential energy as the optimization objective and the anti-collision between trajectories as the constraint.Besides,the geometric check method to judge if there is any interference between fracturing influence domains was provided.Finally,the established optimization design model was verified based on the actual drilling data of Fuling Shale Gas Field in the Sichuan Basin.And the following research results were obtained.First,the obstacle sizes in fracturing areas will be seriously underestimated if the fracturing influence domains are neglected.Second,if the fracturing influence domains are neglected,the designed bypass trajectory can bypass the wellbore trajectories of old wells,but may intersect the fracturing influence domains of existing wells,thus inducing drilling accidents.In conclusion,the proposed optimization design model of bypass trajectory in the shale gas fracturing area can satisfy the constraint of anti-collision and bypass and achieve the optimization objective of minimizing total trajectory length and trajectory potential energy,and the corresponding design calculation avoids complex calculation and check.
