The Research On Steam Distribution In Horizontal Well During Multi-point Steam Injection

The technology of multi-point steam injection has obvious positive effect on the improvement of the exploitation evenness of the heavy oil reservoir along horizontal well.However,the design of steam injection parameters in present multi-point steam injection technology,such as the amount and position of steam injection points,is based on the production experience in the field and lacks the guidance of reasonable methods.Although improving the development effect,this technology doesn't realize the optimal application.Therefore,the reasonable optimization method of steam injection parameters has become the focus of further improving the multi-point steam injection technology.Point at the uneven exploitation along horizontal well and unused section at injector's toe in SAGD production and physical experiments,this paper establishes a more accurate prediction model of steam distribution along horizontal injection well.This model combines reservoir's vapor-sucking model with wellbore's pressure model and considers the stock fluid(a mixture of heavy oil and water)filling horizontal wellbore before steam injection.So this model accords with the reality in oilfield.By using the established steam distribution prediction model,this paper analyses the influence of stock fluid on the pressure profile in steam injection well and researches the effect of stock fluid's viscosity,steam injection rate and the length of horizontal well on evenness of steam chamber growth and effective used length of horizontal well.At the same time,this paper also analyses the influence of the quantity and distribution of steam injection points,the steam injection rate and pressure on the development of the multi-point steam injection technology in SAGD.At last,according to the former research results,this paper establishes an optimization method of steam injection parameter of in multi-point steam injection technology.The results of example applying this optimization method shows the established optimization method of steam injection parameter can effectively improve the production rate of SAGD heavy oil reservoir,the level of reservoir's utilization and the accumulative oil production.The research results of this paper have some guiding function for the prediction of the steam distribution along the long horizontal well,the optimization of the length of the steam injection horizontal well and the optimization design of the steam injection parameters.