Gas-oil gravity drainage is a recognized major contributor to production in fractured reservoirs. While various empirical and analytical methods have been proposed to model this process, many of them contain assumptio...Gas-oil gravity drainage is a recognized major contributor to production in fractured reservoirs. While various empirical and analytical methods have been proposed to model this process, many of them contain assumptions that are questionable or require parameters that are not accessible at the field level. The aim of this work is to provide new, easy-to-use scaling equations for estimating the recoverable oil through gravity drainage in naturally fractured reservoirs, considering the effects of resistance capillary pressure. To accomplish this, data from four oilfields undergoing gravity drainage, including rock properties (eight sets), block height (three sets), and fluid properties (four sets), were used to generate a wide range of recovery curves using a single porosity numerical simulation model. Aronofsky's and Lambert's functions were then utilized to match the generated recovery curves. Statistical analysis revealed that the Aronofsky's function is more accurate in replicating the recovery patterns, while the Lambert's function tends to overestimate the early-time oil recovery and underestimate the oil recovery at a later stage in the majority of cases. A sensitivity analysis was subsequently performed, revealing that parameters such as absolute permeability, viscosity of oil, height of block, gas and oil density, characteristics of relative permeability and capillary pressure curves and interfacial tension (IFT) influence the amount of time taken to achieve the final recovery. Of these parameters, absolute permeability has the most significant effect on the amount of time needed to attain the final recovery, while the effect of difference between oil and gas densities is the lowest. Consequently, two different expressions were developed using nonlinear multiple regression analysis of simulated gravity drainage data which can be combined with the Aronofsky model to substitute the rate convergence constant. The new scaling equations include the effects of capillary pressure and other relevant factors in gravity drainage simulations. Both forms show satisfactory accuracy, as evidenced by the statistical parameters obtained (R2 = 0.99 and MSE = 0.0019 for both established correlations). The new correlations were verified using a wide range of oilfield data and are expected to provide a better understanding of the recovery process in naturally fractured reservoirs.展开更多
目的观察DHS内固定联合药物治疗骨质疏松性股骨粗隆间骨折的临床疗效。方法对46例患者随机采用DHS内固定术手术治疗(对照组)或DHS配合鲑鱼降钙素喷鼻剂加服钙尔奇D片治疗(治疗组),观察比较两组患者在术后4、8、12周末X线表现,6个月后两...目的观察DHS内固定联合药物治疗骨质疏松性股骨粗隆间骨折的临床疗效。方法对46例患者随机采用DHS内固定术手术治疗(对照组)或DHS配合鲑鱼降钙素喷鼻剂加服钙尔奇D片治疗(治疗组),观察比较两组患者在术后4、8、12周末X线表现,6个月后两组患者治疗前后患侧股骨近端(bone mineral density,BMD)值变化和术后疗效。其中治疗组26例,对照组20例,两组在性别、年龄、骨折类型等一般情况方面都具有可比性。结果治疗组患者的骨痂、骨质生成的时间均较对照组明显缩短,生成数量增加,治疗效果明显。治疗6个月后,治疗组治疗后比治疗前患侧股骨近端BMD有所增加(P<0.05),而对照组无明显差异(P>0.05),且治疗组术后疗效的优良率高于对照组(P<0.05),差异有统计学意义。结论DHS内固定联合药物治疗骨质疏松性股骨粗隆间骨折能有效促进骨痂的生长,加速骨折的愈合,减少了患者的卧床时间,促进了早期功能锻炼和患髋的功能恢复。展开更多
文摘Gas-oil gravity drainage is a recognized major contributor to production in fractured reservoirs. While various empirical and analytical methods have been proposed to model this process, many of them contain assumptions that are questionable or require parameters that are not accessible at the field level. The aim of this work is to provide new, easy-to-use scaling equations for estimating the recoverable oil through gravity drainage in naturally fractured reservoirs, considering the effects of resistance capillary pressure. To accomplish this, data from four oilfields undergoing gravity drainage, including rock properties (eight sets), block height (three sets), and fluid properties (four sets), were used to generate a wide range of recovery curves using a single porosity numerical simulation model. Aronofsky's and Lambert's functions were then utilized to match the generated recovery curves. Statistical analysis revealed that the Aronofsky's function is more accurate in replicating the recovery patterns, while the Lambert's function tends to overestimate the early-time oil recovery and underestimate the oil recovery at a later stage in the majority of cases. A sensitivity analysis was subsequently performed, revealing that parameters such as absolute permeability, viscosity of oil, height of block, gas and oil density, characteristics of relative permeability and capillary pressure curves and interfacial tension (IFT) influence the amount of time taken to achieve the final recovery. Of these parameters, absolute permeability has the most significant effect on the amount of time needed to attain the final recovery, while the effect of difference between oil and gas densities is the lowest. Consequently, two different expressions were developed using nonlinear multiple regression analysis of simulated gravity drainage data which can be combined with the Aronofsky model to substitute the rate convergence constant. The new scaling equations include the effects of capillary pressure and other relevant factors in gravity drainage simulations. Both forms show satisfactory accuracy, as evidenced by the statistical parameters obtained (R2 = 0.99 and MSE = 0.0019 for both established correlations). The new correlations were verified using a wide range of oilfield data and are expected to provide a better understanding of the recovery process in naturally fractured reservoirs.
文摘目的:探讨治疗老年股骨颈骨折手术采用腰硬联合麻醉(combined spinal-epidural anesthesia,CSEA)的临床效果,为临床麻醉提供理论依据。方法:收集本院2014年2至2014年8月股骨颈骨折老年患者74例,随机分为CSEA观察组和全身麻醉组对照组,每组37例。记录患者术中出血量、术后镇痛效果、发生高低血压、肺部感染、缺氧、心动过缓、恶心呕吐、头晕嗜睡比例,测试两组患者对麻醉效果及主刀医师的满意率、肌肉松弛满意率、麻醉优良率、不良反应率、麻醉起效和苏醒时间,对比分析手术效果。结果:观察组低血压发生率高于对照组(18.92%vs.5.41%),而高血压发生率低于对照组(0.00%vs.16.22%),差异有统计学意义(P<0.05)。两组术中出血量、缺氧、心动过缓、麻醉效果及主刀医师满意率比较,差异无统计学意义(P>0.05)。观察组组术后6 h VAS评分、恶心呕吐、头晕嗜睡和肺部感染明显比对照组低,差异有统计学意义(P<0.05)。麻醉优良率(97.30%vs.78.37%)及肌肉松弛满意率(94.59%vs.75.58%)高于对照组,不良反应率低于对照组(5.41%vs.35.14%),麻醉起效和苏醒时间明显早于对照组,差异均有统计学意义(P<0.05)。结论:全身麻醉和CSEA治疗老年股骨颈骨折手术患者,麻醉和术后镇痛效果均较好,而CSEA起效更快、镇痛效果更佳,具有较高安全性和可靠性,苏醒时间早,并发症更少,降低病死率,为手术的顺利实施提供保障,提高康复水平和老年生活质量,值得在临床广泛推广应用。
文摘目的观察DHS内固定联合药物治疗骨质疏松性股骨粗隆间骨折的临床疗效。方法对46例患者随机采用DHS内固定术手术治疗(对照组)或DHS配合鲑鱼降钙素喷鼻剂加服钙尔奇D片治疗(治疗组),观察比较两组患者在术后4、8、12周末X线表现,6个月后两组患者治疗前后患侧股骨近端(bone mineral density,BMD)值变化和术后疗效。其中治疗组26例,对照组20例,两组在性别、年龄、骨折类型等一般情况方面都具有可比性。结果治疗组患者的骨痂、骨质生成的时间均较对照组明显缩短,生成数量增加,治疗效果明显。治疗6个月后,治疗组治疗后比治疗前患侧股骨近端BMD有所增加(P<0.05),而对照组无明显差异(P>0.05),且治疗组术后疗效的优良率高于对照组(P<0.05),差异有统计学意义。结论DHS内固定联合药物治疗骨质疏松性股骨粗隆间骨折能有效促进骨痂的生长,加速骨折的愈合,减少了患者的卧床时间,促进了早期功能锻炼和患髋的功能恢复。
