Objective As the most widely used and effective technique in reservoir reconstruction of unconventional natural gas,hydraulic fracturing has been achieved good effect in CBM development.It is important to note that co...Objective As the most widely used and effective technique in reservoir reconstruction of unconventional natural gas,hydraulic fracturing has been achieved good effect in CBM development.It is important to note that coal seam is both source rock and reservoir,展开更多
The fracture-cavity carbonate reservoirs in the Tahe Oilfield in China are mainly exploited by fracturing.We need the hydraulic fractures to communicate with caves to create a flow channel.However,due to the existence...The fracture-cavity carbonate reservoirs in the Tahe Oilfield in China are mainly exploited by fracturing.We need the hydraulic fractures to communicate with caves to create a flow channel.However,due to the existence of the fracture-cavity systems,the hydraulic fracture propagation morphology is complicated,while the propagation characteristics are not clear.To analyze the hydraulic fracture propagation in fracture-cavity carbonate formations,based on the discontinuous discrete fracture model,we developed a solid-seepage-freeflow coupled fracturing model for fracture-cavity formations,which can simulate the complex interaction behavior of fractures and caves.Based on the simulation results,we found the interaction rule between hydraulic fractures and fracture-cavity systems:the stress concentration around caves is the main factor that determines the fracture propagation path.Deflection due to stress concentration is usually not conducive to communication,while natural fractures distributed around caves could break the rejection action.Increasing the hydraulic energy in the hydraulic fracture can make fracture propagate directly and reduce the influence of deflection.The steering fracture formed by temporary plugging is beneficial to the communication of fracture-cavity systems in the non-principal stress direction.According to the simulation results of different fracture-cavity characteristics,we raised four optimization communication modes for fracture-cavity carbonate formation to provide references for fracturing optimization design and parameter optimization.展开更多
基金supported by the National Natural Science Foundation of China(grant No.41572140)the National Major Special Project of Science and Technology of China(grant No.2016ZX05044-001)+1 种基金the Fundamental Research Funds for the Central Universities(grant No.2015XKZD07)the Qing Lan Project
文摘Objective As the most widely used and effective technique in reservoir reconstruction of unconventional natural gas,hydraulic fracturing has been achieved good effect in CBM development.It is important to note that coal seam is both source rock and reservoir,
基金the National Natural Science Foundation Program(No.51874321)。
文摘The fracture-cavity carbonate reservoirs in the Tahe Oilfield in China are mainly exploited by fracturing.We need the hydraulic fractures to communicate with caves to create a flow channel.However,due to the existence of the fracture-cavity systems,the hydraulic fracture propagation morphology is complicated,while the propagation characteristics are not clear.To analyze the hydraulic fracture propagation in fracture-cavity carbonate formations,based on the discontinuous discrete fracture model,we developed a solid-seepage-freeflow coupled fracturing model for fracture-cavity formations,which can simulate the complex interaction behavior of fractures and caves.Based on the simulation results,we found the interaction rule between hydraulic fractures and fracture-cavity systems:the stress concentration around caves is the main factor that determines the fracture propagation path.Deflection due to stress concentration is usually not conducive to communication,while natural fractures distributed around caves could break the rejection action.Increasing the hydraulic energy in the hydraulic fracture can make fracture propagate directly and reduce the influence of deflection.The steering fracture formed by temporary plugging is beneficial to the communication of fracture-cavity systems in the non-principal stress direction.According to the simulation results of different fracture-cavity characteristics,we raised four optimization communication modes for fracture-cavity carbonate formation to provide references for fracturing optimization design and parameter optimization.
