After fracturing in the pilot area,channeling occurs at a low fracture angle(15).Based on the resistance-water saturation relationship,three-dimensional physical simulation methods are used in the laboratory to study...After fracturing in the pilot area,channeling occurs at a low fracture angle(15).Based on the resistance-water saturation relationship,three-dimensional physical simulation methods are used in the laboratory to study the effect of different fracture angles and lengths on the residual oil distribution during the displacement process.Meanwhile,recovery percent,displacement efficiency and expanding sweep co-efficient to the improvement of recovery percent are also discussed.The results show that the fracture angle and length are closely related to the oil saturation distribution in these models.As the fracture angle increases,the sweep coefficient decreases(0.2412→0.1463),and the recovery percent also in-creases(46.16→56.88%),but the extent of increase has been reduced(7.96→2.96%).The extension of the fracture length is more prone to have a cross-flow phenomenon;the sweep coefficient is reduced(0.2412→0.1463).Compared to the model with 1/2 oil-water well spacing,the recovery percent is decreased by 14.29%.In different fracture models,the increasable sweep coefficient has a greater impact on oil recovery than the increasable displacement efficiency(71.30→28.70%).展开更多
Unconventional reservoirs are normally characterized by dual porous media, which has both multi-scalepore and fracture structures, such as low permeability or tight oil reservoirs. The seepage characteristicsof such r...Unconventional reservoirs are normally characterized by dual porous media, which has both multi-scalepore and fracture structures, such as low permeability or tight oil reservoirs. The seepage characteristicsof such reservoirs is mainly determined by micro-fractures, but conventional laboratory experimentalmethods are difficult to measure it, which is attribute to the dynamic cracking of these micro-fractures.The emerging digital core technology in recent years can solve this problem by developing an accuratepore network model and a rational simulation approach. In this study, a novel pore-fracture dualnetwork model was established based on percolation theory. Fluid flow in the pore of two scales, microfracture and matrix pore, were considered, also with the impact of micro-fracture opening and closingduring flow. Some seepage characteristic parameters, such as fluid saturations, capillary pressure, relative permeabilities, displacement efficiency in different flow stage, can be predicted by proposedcalculating method. Through these work, seepage characteristics of dual porous media can be achieved.展开更多
文摘After fracturing in the pilot area,channeling occurs at a low fracture angle(15).Based on the resistance-water saturation relationship,three-dimensional physical simulation methods are used in the laboratory to study the effect of different fracture angles and lengths on the residual oil distribution during the displacement process.Meanwhile,recovery percent,displacement efficiency and expanding sweep co-efficient to the improvement of recovery percent are also discussed.The results show that the fracture angle and length are closely related to the oil saturation distribution in these models.As the fracture angle increases,the sweep coefficient decreases(0.2412→0.1463),and the recovery percent also in-creases(46.16→56.88%),but the extent of increase has been reduced(7.96→2.96%).The extension of the fracture length is more prone to have a cross-flow phenomenon;the sweep coefficient is reduced(0.2412→0.1463).Compared to the model with 1/2 oil-water well spacing,the recovery percent is decreased by 14.29%.In different fracture models,the increasable sweep coefficient has a greater impact on oil recovery than the increasable displacement efficiency(71.30→28.70%).
基金The writers greatly appreciate the financial support of the Major Special Project of PetroChina Co Ltd.(2017E-0406)the National Science and Technology Major Project during the 13th Five-year Plan Period(2016ZX05010-00504).
文摘Unconventional reservoirs are normally characterized by dual porous media, which has both multi-scalepore and fracture structures, such as low permeability or tight oil reservoirs. The seepage characteristicsof such reservoirs is mainly determined by micro-fractures, but conventional laboratory experimentalmethods are difficult to measure it, which is attribute to the dynamic cracking of these micro-fractures.The emerging digital core technology in recent years can solve this problem by developing an accuratepore network model and a rational simulation approach. In this study, a novel pore-fracture dualnetwork model was established based on percolation theory. Fluid flow in the pore of two scales, microfracture and matrix pore, were considered, also with the impact of micro-fracture opening and closingduring flow. Some seepage characteristic parameters, such as fluid saturations, capillary pressure, relative permeabilities, displacement efficiency in different flow stage, can be predicted by proposedcalculating method. Through these work, seepage characteristics of dual porous media can be achieved.
