The sandstones of the paleogene in the Huimin Depression have undergone numerous diagenetic processes, such as compaction, cementation, dissolution, metasomasis and recrystallization. The first three — compaction, ...The sandstones of the paleogene in the Huimin Depression have undergone numerous diagenetic processes, such as compaction, cementation, dissolution, metasomasis and recrystallization. The first three — compaction, cementation and dissolution — affect reservoir properties most intensively. An average porosity loss due to compaction is 0.78% per 100 meters, slightly higher in the central and southern parts and lower in the northern. Cementation has resulted in the porosity loss from 8% to 20% at a depth below 1,500 meters. Dissolution, which in most cases is the dissolution of feldspar and of carbonate cement, primarily occurs in two depth intervals, from 1,400 to 2,500 meters and 2,700 to 4,000 meters respectively. New porosity is created through dissolution from 4% to 14%. The sandstones experienced stage A and stage B of early diagenesis and stage A of late diagenesis. At present, most of them are experiencing Phase A2 of late diagenesis. The types of pores in the sand reservoir can be grouped into primary and secondary ones.展开更多
Based on the impact of the stress perturbation effect created by simultaneous propagation of multiple fractures in the process of simultaneous hydraulic fracturing, a thorough research on the mechanism and adaptation ...Based on the impact of the stress perturbation effect created by simultaneous propagation of multiple fractures in the process of simultaneous hydraulic fracturing, a thorough research on the mechanism and adaptation of simultaneous fracturing of double horizontal wells in ultra-low permeability sandstone reservoirs was conducted by taking two adjacent horizontal wells(well Yangping-1 and well Yangping-2 located in Longdong area of China Changqing Oilfield) as field test wells. And simultaneous fracturing optimal design of two adjacent horizontal wells was finished and employed in field test. Micro-seismic monitoring analysis of fracture propagation during the stimulation treatment shows that hydraulic fractures present a pattern of complicated network expansion, and the well test data after fracturing show that the daily production of well Yangping-1 and well Yangping-2 reach105.8 t/d and 87.6 t/d, which are approximately 9.4 times and 7.8 times the daily production of a fractured vertical well in the same area, respectively. Field test reflects that simultaneous hydraulic fracturing of two adjacent horizontal wells can enlarge the expansion area of hydraulic fractures to obtain a lager drainage area and realize the full stimulation of ultra-low permeability sandstone reservoirs in China Changqing oilfield. Therefore, simultaneous fracturing of two adjacent horizontal wells provides a good opportunity in stimulation techniques for the efficient development of ultra-low permeability reservoirs in China Changqing oilfield,and it has great popularization value and can provide a new avenue for the application of stimulation techniques in ultra-low permeability reservoirs in China.展开更多
The concern on formation damage control of high permeability sandstone reservoir has been growing in oil industry in recent years. The invasion of particles and the filtrate of drilling fluid are proven as one of the ...The concern on formation damage control of high permeability sandstone reservoir has been growing in oil industry in recent years. The invasion of particles and the filtrate of drilling fluid are proven as one of the key factors accounting for reservoir damage. Based on the ideal packing theory, the practical software has been developed to optimize the blending proportion of several bridging agents, and the core flooding tests were conducted to evaluate return permeability of core samples contaminated with different drilling fluids. Experimental results show that the ideal packing approach can reduce the dynamic filtration rate, improve the return permeability and drawdown the breakthrough pressure, indicating that this kind of drilling fluids can meet the demands of formation damage control for high permeability sandstone reservoirs. Some applying procedures for formation damage control are also proposed in this paper.展开更多
文摘The sandstones of the paleogene in the Huimin Depression have undergone numerous diagenetic processes, such as compaction, cementation, dissolution, metasomasis and recrystallization. The first three — compaction, cementation and dissolution — affect reservoir properties most intensively. An average porosity loss due to compaction is 0.78% per 100 meters, slightly higher in the central and southern parts and lower in the northern. Cementation has resulted in the porosity loss from 8% to 20% at a depth below 1,500 meters. Dissolution, which in most cases is the dissolution of feldspar and of carbonate cement, primarily occurs in two depth intervals, from 1,400 to 2,500 meters and 2,700 to 4,000 meters respectively. New porosity is created through dissolution from 4% to 14%. The sandstones experienced stage A and stage B of early diagenesis and stage A of late diagenesis. At present, most of them are experiencing Phase A2 of late diagenesis. The types of pores in the sand reservoir can be grouped into primary and secondary ones.
基金Project(51404204)supported by the National Natural Science Foundation of ChinaProject(20135121120002)supported by Specialized Research Fund for the Doctoral Program of Higher Education of ChinaProject(2014QHZ005)supported by Scientific Research Starting Projecting of SWPU,China
文摘Based on the impact of the stress perturbation effect created by simultaneous propagation of multiple fractures in the process of simultaneous hydraulic fracturing, a thorough research on the mechanism and adaptation of simultaneous fracturing of double horizontal wells in ultra-low permeability sandstone reservoirs was conducted by taking two adjacent horizontal wells(well Yangping-1 and well Yangping-2 located in Longdong area of China Changqing Oilfield) as field test wells. And simultaneous fracturing optimal design of two adjacent horizontal wells was finished and employed in field test. Micro-seismic monitoring analysis of fracture propagation during the stimulation treatment shows that hydraulic fractures present a pattern of complicated network expansion, and the well test data after fracturing show that the daily production of well Yangping-1 and well Yangping-2 reach105.8 t/d and 87.6 t/d, which are approximately 9.4 times and 7.8 times the daily production of a fractured vertical well in the same area, respectively. Field test reflects that simultaneous hydraulic fracturing of two adjacent horizontal wells can enlarge the expansion area of hydraulic fractures to obtain a lager drainage area and realize the full stimulation of ultra-low permeability sandstone reservoirs in China Changqing oilfield. Therefore, simultaneous fracturing of two adjacent horizontal wells provides a good opportunity in stimulation techniques for the efficient development of ultra-low permeability reservoirs in China Changqing oilfield,and it has great popularization value and can provide a new avenue for the application of stimulation techniques in ultra-low permeability reservoirs in China.
文摘The concern on formation damage control of high permeability sandstone reservoir has been growing in oil industry in recent years. The invasion of particles and the filtrate of drilling fluid are proven as one of the key factors accounting for reservoir damage. Based on the ideal packing theory, the practical software has been developed to optimize the blending proportion of several bridging agents, and the core flooding tests were conducted to evaluate return permeability of core samples contaminated with different drilling fluids. Experimental results show that the ideal packing approach can reduce the dynamic filtration rate, improve the return permeability and drawdown the breakthrough pressure, indicating that this kind of drilling fluids can meet the demands of formation damage control for high permeability sandstone reservoirs. Some applying procedures for formation damage control are also proposed in this paper.
