Study On The Cause And Prevention Of CO And H 2 S During Steam Stimulation

Recently, a dangerous gas levels of CO and H2S was monitored in the process of steam stimulation in domestic HS oilfield. This issue directly endangers the health of field workers, and seriously affects the safety of the oilfield production. Due to the rare of this issue, there are few related reports on its mature research and field processing method. Therefore, it is necessary to do some researches on this issue. Base on Wellblock-M of HS oilfield, this thesis mainly studied the causes and influence factors of CO and H2S in the process of steam stimulation systematically. Then, on the basis of previous studies, a preliminary study on the treatment of CO and H2S was conducted subsequently.Firstly, an analysis of on-site date (primarily the concentration of CO and H2S) was carried out. Then, we conducted some tests on the samples from oilfield. After that, we found that some parameters such as temperature, injected steam volume, soak time, composition of crude oil, reservoir minerals and so on, will influence the concentration of CO and H2S. Upon that, some laboratory physical simulation experiments on these parameters were performed. The experimental results show that:temperature, injected steam volume and soak time influence the concentration of produced CO and H2S significantly. However, the steam injection rounds mainly affect the active component of crude oil, and is not directly related to the concentration of produced gases. While, the sulfur content in crude oil and the reservoir minerals both affect only the production of H2S. Moreover, based on these analysis, we concluded that the main reason for high-level carbon monoxide concentration lies in a lack of the reservoir mineral catalytic ability. After that, we did a preliminary study on the treatment of CO and H2S:on the basis of laboratory physical simulation experiments, a response surface model of CO and H2S was established. Through the response surface model, the interactions between parameters that influence the concentration of CO were found, and then a method of adjustment of field parameters to reduce the concentration of CO was put forward.After that, the effect of catalyst on the process of steam stimulation was investigated. The result shows that the selected two types of catalysts both could make the viscosity of crude oil and the concentration of CO decrease efficiently. Then, through the investigation of two desulfurizers, we confirmed the feasibility of the dry desulphurization to decrease the concentration of H2S on spot.At last, we evaluated the absorber of hydrogen sulfide in situ briefly.The investigation of this thesis could not only contribute to solving the high-level carbon monoxide concentration problem in the process of steam stimulation in Wellblock-M of HS oilfield,but also provide useful references and guidance for other oilfield.