Study On Forecasting And Prevention Of Natural Gas Hydrate

Due to the throttling effect,a sharp change of the pressure and temperature is likely to lead to hydrate formation in the natural gas pipeline.After the formation of natural gas hydrate,it would block up safety valve,vent valve,relief pressure pipeline,and various equipment,leading pressure relief abnormal and would lead trouble to gathering and transportation,exploitation of natural gas,even cause serious safety accidents.In this paper,a lot of literature retrieval and field investigation were carried out,the system analysis and research were carried out,which provided theoretical basis for the prevention and cure of hydrate.This paper introduces relevant theory of oil and gas storage and transportation and fluid mechanics,using the method of simulation analysis choosing the South China Sea Ledong oilfield natural gas component as an example,selecting three groups of hydrate inhibitors that commonly used,analysing on economy,efficiency,nature direction,then choosing the best inhibitor;and the influencing factors of gas hydrate and critical temperature the pressure was studied,in the aspects of natural gas composition,water content of ions,alkane content,water content in natural gas,acid gas,and the concentration of ions in the water,the salinity of natural gas hydrate;through the South China Sea Ledong offshore oil platform safety valve and vent valve case analysis,natural simulation of gas pressure relief vent pressure changes pressure pipeline,and make a prediction of the formation of natural gas hydrate,and puts forward the corresponding solutions;in this paper,after natural gas pipeline releasing pressure,proposed by adjusting the size of the pipeline,controling pressure relief of natural gas pipeline pressure to prevent hydrate way and according to the actual engineering was studied,for natural gas pipeline with differentset pipe flow,the best choice of pipeline was listed;using finite element software of FLUENT,safety valve and a throttle valve in different open degree of the internal flow field was simulated,and hydrate analysis within the valve flow field in the highest pressure or minimum temperature of key points,predicted the formation of hydrate in the valve;through injecting inhibitor control gas,to inhibit the formation of gas hydrate by injecting hydrate inhibitor,this paper according to the characteristics of the pressure relief pipeline by small throttle valve series method to simulate the throttle valve or pressure relief pipe throttling effect,for natural gas under a different set of pipe flow of the need to inject hydrate and fitting formula for general.This paper also puts forward the by depressurization or heating method to prevent pressure relief pipeline hydrate production,and through the analysis of data,curve fitting,formulas of the inductive method obtained gas gathering the solution formula of the critical pressure and temperature,and has certain practicability in engineering.