One of the most common methods for calculating the production oil rate in a gas lift well is nodal analysis.This manner is an accurate one,but unfortunately it is very time consuming and slow.In some modern studies in...One of the most common methods for calculating the production oil rate in a gas lift well is nodal analysis.This manner is an accurate one,but unfortunately it is very time consuming and slow.In some modern studies in petroleum engineering such as close loop control of the wells this slowness makes it impossible to have an online optimization.In fact,before the end of the optimization the input parameters have changed.Thus having a faster model is necessary specially in some of the new studies.One of the sources of slowness of the nodal analysis is the temperature profile estimation of the wells.There are two general approaches for temperature profile estimation,some like heat balance are accurate but slow.Others,similar to linear profile assumption are fast but inaccurate and usually are not used commonly.Here,as a new approach,a combination model of heat balance and linear temperature profile estimation has represented which makes the nodal analysis three times faster and it is as accurate as heat balance calculations.To create this,two points(gas injection point and end of tubing)are selected,then using heat balance equations the temperature of those two points are calculated.In normal nodal analysis the temperature of each wanted point in the well is estimated by heat balance and it is the source of slowness but here just two points are calculated using those complex equations.It seems that between these points assuming a linear temperature profile is reasonable because the parameters of the well and production such as physical tubing,and casing shape and properties and gas oil ratio are constants.But of course,it still has some deviation from the complete method of heat balance which using regression and assigning a coefficient to the model even this much of the deviation could be overcame.Finally,the model was tested in various wells and it was compared with the normal nodal analysis with complete heat balance models.Results showed that the new model is as accurate as normal heat balance but three times fas展开更多
为了研究第二类吸收式热泵在余热回收中关键性能指标的影响因素,有效提高系统性能系数(coefficient of performance,COP),利用流程模拟软件aspen plus建立了第二类吸收式热泵热力系统模型,研究了第二类吸收式热泵性能评价指标温升能力Δ...为了研究第二类吸收式热泵在余热回收中关键性能指标的影响因素,有效提高系统性能系数(coefficient of performance,COP),利用流程模拟软件aspen plus建立了第二类吸收式热泵热力系统模型,研究了第二类吸收式热泵性能评价指标温升能力ΔT、放气范围ΔX和性能系数COP与蒸发温度、蒸发压力、发生压力的关系。结果表明,温升能力ΔT随着高压的升高而增加,随着低压的升高而减小;放气范围ΔX随着蒸发温度的提高线性增长,随着发生压力的提高而减小;性能系数COP随着蒸发温度的升高逐渐增大,随着蒸发压力的提高先升高然后略有下降,随着发生压力的提高而下降,下降趋势逐渐增强。因此在保证一定驱动热源温度的情况下,降低发生压力、增大系统内高低压差是有效提升温升、增大放气范围、提高COP的方法。展开更多
文摘One of the most common methods for calculating the production oil rate in a gas lift well is nodal analysis.This manner is an accurate one,but unfortunately it is very time consuming and slow.In some modern studies in petroleum engineering such as close loop control of the wells this slowness makes it impossible to have an online optimization.In fact,before the end of the optimization the input parameters have changed.Thus having a faster model is necessary specially in some of the new studies.One of the sources of slowness of the nodal analysis is the temperature profile estimation of the wells.There are two general approaches for temperature profile estimation,some like heat balance are accurate but slow.Others,similar to linear profile assumption are fast but inaccurate and usually are not used commonly.Here,as a new approach,a combination model of heat balance and linear temperature profile estimation has represented which makes the nodal analysis three times faster and it is as accurate as heat balance calculations.To create this,two points(gas injection point and end of tubing)are selected,then using heat balance equations the temperature of those two points are calculated.In normal nodal analysis the temperature of each wanted point in the well is estimated by heat balance and it is the source of slowness but here just two points are calculated using those complex equations.It seems that between these points assuming a linear temperature profile is reasonable because the parameters of the well and production such as physical tubing,and casing shape and properties and gas oil ratio are constants.But of course,it still has some deviation from the complete method of heat balance which using regression and assigning a coefficient to the model even this much of the deviation could be overcame.Finally,the model was tested in various wells and it was compared with the normal nodal analysis with complete heat balance models.Results showed that the new model is as accurate as normal heat balance but three times fas
文摘为了研究第二类吸收式热泵在余热回收中关键性能指标的影响因素,有效提高系统性能系数(coefficient of performance,COP),利用流程模拟软件aspen plus建立了第二类吸收式热泵热力系统模型,研究了第二类吸收式热泵性能评价指标温升能力ΔT、放气范围ΔX和性能系数COP与蒸发温度、蒸发压力、发生压力的关系。结果表明,温升能力ΔT随着高压的升高而增加,随着低压的升高而减小;放气范围ΔX随着蒸发温度的提高线性增长,随着发生压力的提高而减小;性能系数COP随着蒸发温度的升高逐渐增大,随着蒸发压力的提高先升高然后略有下降,随着发生压力的提高而下降,下降趋势逐渐增强。因此在保证一定驱动热源温度的情况下,降低发生压力、增大系统内高低压差是有效提升温升、增大放气范围、提高COP的方法。
