Study On Migration Of Elemental Sulfur Particles In High Sulfur Gas Reservoir

High sulfur gas reservoir is widely distributed in the world,in the gas drilling process,with the change of temperature and pressure will change,precipitation of sulfur gases,when sulfur gas cannot be carried away,will produce the sulfur deposition,plug the pore throats,formation damage,seriously affecting the high sulfur gas well productivity.At present,macro experimental and theoretical methods are used to study the mechanism of sulfur deposition,and the microscopic migration and deposition mechanism of elemental sulfur particles are not clear.Therefore,it is necessary to adopt micro scale research methods.Therefore,the simulation study on elemental sulfur deposition mechanism of micro particle migration of gas solid coupling method from the microcosmic angle,cohesive force by key consideration by the sulfur particles during migration,gravity,drag and buoyancy and sulfur particle collision in the process of cluster analysis,sulfur analysis,explore the different flow velocity,particle diameter,hole under the condition of laryngeal micro particle transport and deposition of elemental sulfur.Through the study,we have obtained the following understanding:(1)Carry out the particrle size of elemental sulfur on the distribution,on analogy with that of sulfur particles in formation service from the Log-Normal distribution,combined with sulfur particles morphology experiment;application of mercury porosimetry and scanning electron microscopy experiments,we studied the core hole the throat pore size distribution,mainly distributed in 1?20?m,average 16p?m.(2)on the basis of the classical Hertz-Mindlin(no-slip)model,to establish the contact model considering the bond strength to describe the crystallization,the sulfur particle agglomeration process,the simulation results show that the number of sulfur particles'contacts increases with time.The mean particle size of element sulfur particles will increase,and the probability density function peak of its distribution curve will be smaller.(3)The migration of single sulfur particles in porous medium is mainly affected by gravity,buoyancy,drag control,low flow rate conditions,sulfur deposition of particles is mainly for gravity deposition and collision deposition;the condition of high speed transport of sulfur particles is mainly affected by fluid drag control,with the air out of a porous medium without deposition.(4)The deposition rule of elemental sulfur:For the same size of sulfur particles,the deposition rate decreases as the inlet velocity increases,because the gas flow rate of inlet air is greater,the capacity of sulfur carrying is better.For the same air inlet velocity,the deposition rate increases with the increase of particle diameter,because the smaller size of sulfur particles in suspension,the deposition rate is very small,while the big diameter sulfur particles under the action of gravity effect is relatively large.The deposition is more likely to occur.It is also found that the influence of particle diameter on deposition rate is greater than the influence of inlet velocity on deposition rate.(5)Simulation study of different porous media model found that under the same conditions,the deposition rate is greater than the single hole double throat hole three hole in the throat throat;three,before a void ratio after a pore deposition;deposition rate of complex porous media seepage channel;migration of sulfur deposition particles is complicated and its elements in the transport process of the sulfur deposition rate increased obviously.