Study On The Law Of Sulfur Deposition In High-sulfur Gas Reservoirs

When gas reservoirs with high H2S content produced, the sulfur deposited in formation pores will block pores and reduce permeability. What's more, gas wells stop production.In this paper. Based on the computer simulation of sulfur particles deposited regularities and experimental study on sulfur molecular adsorbed law, the sulfur deposited law of gas reservoirs with high H2S content were studied by sulfur deposited experiment, analytical prediction model which consider sulfur molecules adsorbed and numerical model which consider fluid composition, elemental sulfur adsorbed and hydrogen sulfide content. Research results provide a scientific basis for reasonable development of gas reservoir with high H2S content.Through the study, we obtained related knowledge:(1) Through the EDEM-Fluent software simulate the deposited law of sulfur particles in the channel sedimentation of formation. The results indicate that sulfur deposited amount will increase over time. In the flow direction, the amount of sulfur deposited gradually increase. The settlement of sulfur particles will influence the gas dynamic pressure and the impact positively related to the settlement. The change of the pore diameter will lead to the settlement of sulfur particles have different patterns.(2) Through experiment study adsorbed law of sulfur molecules on kaolinite, montmorillonite and illite, the results show that the adsorption capacity of sulfur molecules on kaolinite, montmorillonite and illite, in a certain time range increases with time, in the certain concentration range increases with concentration, in a certain temperature range decreases with temperature.(3) By sulfurous gas core flow experiment and the microstructure of precipitated sulfur particles experiment, the results indicate that sulfur deposition will reduce the core porosity and permeability. And the quantity of sulfur deposited in pores is related to space. The formation of elemental sulfur is a process from small to large. That is, first by nanoscale elemental sulfur crystals gathered to form planar elemental sulfur, and then gradually form cambium-like elemental sulfur.(4) By establishing deposition prediction model which consider sulfur molecular adsorbed, the calculation of an example is carried out, the results indicate that the sulfur molecular adsorbed will reduce pore space, increase sulfur saturation in gas, and the influence degree as well radius increases.(5) Through the establishment of numerical prediction model which consider fluid composition, sulfur adsorption and H2S content study the impact of different production systems and gas reservoir physical parameters on the amount of sulfur deposition. Results indicate that the smaller the bottomhole pressure or the higher the yield, sulfur deposition amount is larger. Sulfur deposition quantity increases along with the formation pressure, formation temperature and hydrogen sulfide content, decreases with the porosity and permeability.