The BZ oilfield in the Bohai Sea is a rare,highly volatile reservoir with fractures in the metamorphic rocks of buried hills.Clarifying the mechanism of gas injection for improving oil recovery and determining the opt...The BZ oilfield in the Bohai Sea is a rare,highly volatile reservoir with fractures in the metamorphic rocks of buried hills.Clarifying the mechanism of gas injection for improving oil recovery and determining the optimal way to deploy injection-production well networks are critical issues that must be urgently addressed for efficient oilfield development.Experimental research on the mixed-phase displacement mechanism through gas injection into indoor formation fluids was conducted to guide the efficient development of gas injection in oil fields.We established a model of dual-medium reservoir composition and researched the deployment strategy for a three-dimensional well network for gas injection development.The coupling relationship between key influencing factors of the well network and fracture development was also quantitatively analyzed.The results show that the solubility of the associated gas and strong volatile oil system injected into the BZ oilfield is high.This high solubility demonstrates a mixed-phase displacement mechanism involving intermediate hydrocarbons,dissolution and condensation of medium components,and coexistence of extraction processes.Injecting gas and crude oil can achieve a favorable mixing effect when the local formation pressure is greater than 35.79 MPa.Associated gas reinjection is recommended to supplement energy for developing the highly volatile oil reservoirs in the fractured buried hills of the BZ oilfield.This recommendation involves fully utilizing the structural position and gravity-assisted oil displacement mechanism to deploy an injection-production well network.Gas injection points should be constructed at the top of high areas,and oil production points should be placed at the middle and lower parts of low areas.This approach forms a spatial threedimensional well network.By adopting high inclination well development,the oil production well forms a 45°angle with the fracture direction,which increases the drainage area and enhances single-well production capacity.The optimal injection-production well spacing along the fracture direction is approximately 1000 m,while the reasonable well spacing in the vertical fracture direction is approximately 800 m.The research results were applied to the development practice of the buried hills in the BZ oilfield,which achieved favorable development results.These outcomes provide a valuable reference for the formulation of development plans and efficient gas injection development in similar oil and gas fields in buried hills.展开更多
Objective To investigate the effect of Botulinum toxin type A(Botox)injection into the masseter muscle on mandibular development in rats.Methods 1228-day-old Wistar rats were divided into two groups as Botox group(n=6...Objective To investigate the effect of Botulinum toxin type A(Botox)injection into the masseter muscle on mandibular development in rats.Methods 1228-day-old Wistar rats were divided into two groups as Botox group(n=6)and control group(n=6)展开更多
BZ13-2 oil field is a deep submerged strongly volatile reservoir in Bohai Sea. This oil reservoir has the characteristics of high gas oil ratio and small difference in formation pressure and saturation point pressure....BZ13-2 oil field is a deep submerged strongly volatile reservoir in Bohai Sea. This oil reservoir has the characteristics of high gas oil ratio and small difference in formation pressure and saturation point pressure. It usually adopts gas injection development to avoid crude oil degassing and fast decreasing production capacity. However, the phase characteristics and miscibility mechanism of this high-temperature and high-pressure fluid after gas injection are not clear. Therefore, it is necessary to study the feasibility of CO<sub>2</sub> injection to improve oil recovery in near critical volatile oil reservoirs through CO<sub>2</sub> injection experiments. In the early stage of the depletion experiment, the content of heavy components in the remaining oil increased significantly, so the depletion method is not conducive to the development of such reservoirs. With the increase of CO<sub>2</sub> injection, the volumetric expansion coefficient of formation crude oil increases significantly, while the saturation pressure and formation crude oil viscosity remain basically unchanged. The minimum miscible pressure experiment shows that CO<sub>2</sub> injection under formation pressure conditions can achieve multiphase miscibility. Based on experimental research results, the BZ13-2 oilfield is suitable for early gas injection development and can significantly improve recovery.展开更多
文摘The BZ oilfield in the Bohai Sea is a rare,highly volatile reservoir with fractures in the metamorphic rocks of buried hills.Clarifying the mechanism of gas injection for improving oil recovery and determining the optimal way to deploy injection-production well networks are critical issues that must be urgently addressed for efficient oilfield development.Experimental research on the mixed-phase displacement mechanism through gas injection into indoor formation fluids was conducted to guide the efficient development of gas injection in oil fields.We established a model of dual-medium reservoir composition and researched the deployment strategy for a three-dimensional well network for gas injection development.The coupling relationship between key influencing factors of the well network and fracture development was also quantitatively analyzed.The results show that the solubility of the associated gas and strong volatile oil system injected into the BZ oilfield is high.This high solubility demonstrates a mixed-phase displacement mechanism involving intermediate hydrocarbons,dissolution and condensation of medium components,and coexistence of extraction processes.Injecting gas and crude oil can achieve a favorable mixing effect when the local formation pressure is greater than 35.79 MPa.Associated gas reinjection is recommended to supplement energy for developing the highly volatile oil reservoirs in the fractured buried hills of the BZ oilfield.This recommendation involves fully utilizing the structural position and gravity-assisted oil displacement mechanism to deploy an injection-production well network.Gas injection points should be constructed at the top of high areas,and oil production points should be placed at the middle and lower parts of low areas.This approach forms a spatial threedimensional well network.By adopting high inclination well development,the oil production well forms a 45°angle with the fracture direction,which increases the drainage area and enhances single-well production capacity.The optimal injection-production well spacing along the fracture direction is approximately 1000 m,while the reasonable well spacing in the vertical fracture direction is approximately 800 m.The research results were applied to the development practice of the buried hills in the BZ oilfield,which achieved favorable development results.These outcomes provide a valuable reference for the formulation of development plans and efficient gas injection development in similar oil and gas fields in buried hills.
文摘Objective To investigate the effect of Botulinum toxin type A(Botox)injection into the masseter muscle on mandibular development in rats.Methods 1228-day-old Wistar rats were divided into two groups as Botox group(n=6)and control group(n=6)
文摘BZ13-2 oil field is a deep submerged strongly volatile reservoir in Bohai Sea. This oil reservoir has the characteristics of high gas oil ratio and small difference in formation pressure and saturation point pressure. It usually adopts gas injection development to avoid crude oil degassing and fast decreasing production capacity. However, the phase characteristics and miscibility mechanism of this high-temperature and high-pressure fluid after gas injection are not clear. Therefore, it is necessary to study the feasibility of CO<sub>2</sub> injection to improve oil recovery in near critical volatile oil reservoirs through CO<sub>2</sub> injection experiments. In the early stage of the depletion experiment, the content of heavy components in the remaining oil increased significantly, so the depletion method is not conducive to the development of such reservoirs. With the increase of CO<sub>2</sub> injection, the volumetric expansion coefficient of formation crude oil increases significantly, while the saturation pressure and formation crude oil viscosity remain basically unchanged. The minimum miscible pressure experiment shows that CO<sub>2</sub> injection under formation pressure conditions can achieve multiphase miscibility. Based on experimental research results, the BZ13-2 oilfield is suitable for early gas injection development and can significantly improve recovery.
