Design Of Hydrate Prevention And Control Technology And Skid-mount Package In Gathering And Transportation Of High-pressure Natural Gas In Gas Field

Hydrate formation of natural gas is an important issue that has always beset the natural gas gathering and transportation industry.Natural gas hydrates are easy to form and gradually accumulate in the less flow space of pipelines or equipments,and finally result in their blockage.Giving vent to the gas pipelines could solve the problem when they are blocked by hydrates seriously,while it would cause resource-wasting and environment pollution.Because the problem of hydrate formation during the natural gas gathering and transportation under high pressure is particularly serious,it must be solved.Therefore,the study on prevention and control of hydrate formation in the natural gas gathering under high-pressure is of great realistic significance.The work described in this dissertation is based on the project of pilot production skid of high pressure in Xin Jiang gas field,and focuses on hydrate generation during the natural gas gathering and transportation under high pressure.In this work,the work carried out the investigation of prevention of hydrate generation under the specific circumstance,provided a feasible technology scheme,and finally determined the most suitable antifreeze technology.Firstly,according to the present situation of natural gas exploration and development area and the existing gas field,as well as the comprehensive analysis of their geological condition,and then the maximum processing capacity of the device is determined.This work compared the engineering adaptation of heating and alcohol injection antifreeze technology,and then analyzed the influence of gas well liquid on the antifreezing effect of alcohol solution.It is found that heating antifreeze technology is more suitable than the alcohol injection antifreeze processes for the gas fields containing more liquid.Secondly,according to the data calculated by HYSYS simulation software three dehydrate technologies were chosen preliminary and compared.Considering equipment investment and easy operation,J-T throttling and low temperature separation technology was determined as the best scheme.To avoid the formation and accumulation of hydrates in the scheme,alcohol injection antifreeze technology was chosen.Finally,based on the necessary parameters and size of equipments calculated by HYSYS,as well as the energy consumption,equipment investment and evaluation index of products,the equipments calculation in the gathering and transportation were carried out and the skid–mounted model was used,then the PID flow diagrams of main skids were drawn.Combined with the property of flow from gas well,and based on the original project,this work gives a solution for prevention and control of hydrate formation.After the treatment,the operation temperature is 3 °C higher than the hydrate formation temperature,and the indexes of natural after the treatment meet the required standard of pipeline transportation.The entire process flow was divided into different skids,and then the package unit can be dismountable and relocated.The whole design process is in accordance with the relevant national standards and norms.The selection of hydrate antifreeze scheme in this paper has certain reference for the research of hydrate inhibitation in the gathering and transportation of gas field under high pressure.