Hydrogen Sulphide Formation Rule Of Steam Injection Thermal Recovery

With the continuous expansion steam flooding of heavy oil exploitation in our country,when high temperature steam into the formation,makes the crude oil,rock matrix and formation water induce a series of complex chemical reaction,and then produce the acid gases such as CO2 and H₂S.Among them,the H₂S is a highly toxic and harmful gas,has great harmfulness to health and has the chemical activity will have strong corroding effect on oil field production equipment.Therefore,research the rule of H₂S in steam injection thermal recovery is great significance of H₂S prevention measures in production.This paper based on the research of geological characteristics of Liaohe Xiaowa Oilfield Wa-38 and H₂S output of historical,detection and analysis the oil,sand and oil field water,ascertain the origin of H₂S,the existing forms of sulfur and the fractionation of sulfur in thermochemical sulfate reduction?TSR?process under high temperature.In high-temperature high-pressure reaction kettle,for heavy oil,core and water simulation experiment of H₂S generation,analysis of reaction gas and core element showed that aquathermolysis and TSR as the main way to generate H₂S.And TSR is based on aquathermolysis,then the two reaction interaction generation of H₂S.At the same time,the H₂S production increases with increasing SO₄^2- concentrations,and sulfate ion easy to heavy hydrocarbon compounds occurring thermochemical reduction.Basic on the theory of formation routes H₂S,experimental analysis the H₂S generation correlated variation with temperature and time,discovery the H₂S in acidic condition to generate increased and inhibit the formation of H₂S under alkaline conditions,the generation mechanism by effect of acidic promote and alkaline suppress.Finally,on the basis of the above research,carry out the heavy oil and core analytical reagent generation mechanism simulation experiment,explores the aquathermolysis of heavy oil and thermochemical sulfate reduction pathway and elementary reaction.Analysis shows that,thiophene compounds of heavy oil aquathermolysis reaction and pyrite of cores oxidation by thermochemical sulfate reduction reaction is the two elementary generation H₂S reaction.Based on the detection analysis of heavy oil,core and water and analysis the sulfur source,carry out the generating H₂S in steam injection thermal simulation experiment,obtained by acid promotion,alkaline suppression research results.It provides scientific theoretical for H₂S prevention and control in steam injection thermal recovery oil field.