Spar钻井生产储卸油平台储油系统油水置换传热特性试验研究

Experimental Study on Heat Transfer Characteristics of Oil-Water Displacement in SDPSO Storage System

发展具有钻、采、储、运综合能力的深水平台是海洋工程领域的热点之一,一种新型深水立柱式Spar钻井生产储卸油平台(SDPSO)概念应运而生。该平台采用油水置换工艺进行储卸油操作。当储油舱内某处的温度过低时,将发生凝油与析蜡现象,且较低的温度会使油相的黏度大幅提高,这降低了油水两相的流动,阻碍了油水置换工艺的顺利进行。因此有必要对SDPSO储油系统油水置换传热特性进行研究。论文通过SDPSO油水置换的中型试验,详细分析了常规海况及一年一遇海况下储油过程中储油系统油水置换传热特性。试验结果表明,储油舱内高温热油的热量主要是通过舱壁向外传输热量,而通过油水界面传输的热量很少。对于密度易受温度影响的原油,在置换过程中沿径向存在自然对流。储油舱内原油温降可用类似于苏霍夫公式的简易方式表达。经计算,在不设置加热设备的情况下,实尺度下保温层的2小时温降系数需低于1%。

Development of deep-water platforms with comprehensive capabilities of drilling,production,storage,and transportation is one of the hot spots in the field of offshore engineering.A concept of new Spar FPSO platform,i.e.,SDPSO,is proposed.The oil-water displacement process is applied in oil storage and offloading.Heat transfer behavior in the tank should be investigated,as the heat loss of oil will greatly increase the viscosity of the oil,which reduces flowing of the oil and thus affect the process.In this paper,a pilot test of SDPSO storage system under the normal sea state and under the one-year sea state is conducted,and the heat transfer characteristics in oil-water displacement are analyzed.It is found that the heat of the high-temperature hot oil in the SDPSO storage tank is mainly transferred through the tank shell,while the heat transferred through the oil-water interface is a little.For the crude oil whose density is easily affected by temperature,there is natural convection in the radial direction during the displacement process.For this crude oil,the temperature drop in the storage tank can be written as a simple form similar as the Sukhov’s formula.By the calculation,an insulation layer should be arranged on the tank shell for the real scale SDPSO platform to ensure the 2-hour temperature drop coefficient be less than 1%without heating equipment.