摘要
当前油气并重、常非并举的能源发展战略有效推动了页岩油的开发进程,对其高效安全集输工艺技术重视度显著提高.通过室内实验测定了 JH页岩油的基础物性,明确了其凝点低、密度小、含蜡量高、轻质组分多、无沥青质、少胶质和蜡晶结构强度弱的特点.集输过程中其蜡晶结构易被破坏会导致动态黏度于凝点附近迅速降低.集油温度低于凝点时,停输后其动态屈服应力显著低于静态值.停输后,静态降温过程中更多蜡晶析出导致凝油结构强度迅速恢复;无降温条件下其结构强度恢复速度极慢,凝点以下9℃停输12h后所得动态屈服应力仅为静态值的8.5％.为保证输送安全,需在避免地温条件过低或停输后存在大幅降温条件下开展再启动操作,若有必要可采用间歇性启动方式降低凝油屈服应力,保证再启动安全.
Abstract
The current energy development strategy of developing simultaneously oil and gas,as well as conventional and unconventional energy sources,effectively promotes the development process of shale oil,and the attention to its efficient and safe gathering and transportation process technology has been significantly increased.In this paper,the basic physical properties of JH shale oil were determined by indoor experiments,and its characteristics of low freezing point,low density,high wax content,high number of light components,no asphaltene,few colloids and weak wax crystal structure were identified.The wax crystal structure is easy to be destroyed during the gathering and transportation process,which will lead to the rapid decrease of dynamic viscosity near the freezing point.When the temperature of oil gathering is lower than the freezing point,the dynamic yield stress is significantly lower than the static value after stopping the transportation.After stopping the transportation,more wax crystals are precipitated during the static cooling process,which leads to the rapid recovery of condensate structural strength;under the condition of no temperature drop,the structural strength recovery is very slow,and the dynamic yield stress obtained after stopping the transportation for 12h at 9 ℃ below the freezing point is only 8.5％of the static value.In order to ensure the transportation safety,it is necessary to avoid the restart operation under the condition of low ground temperature or large temperature drop after stopping the transportation,and if necessary,intermittent startup can be used to reduce the yield stress of condensate,so as to ensure the restart safety.
国家科技期刊平台
NSTL
万方数据