Wellbore-Reservoir System Heat Transport During Superheated Steam Injection

Owning to the strategic role of oil resources in the global economy,to maintain the balance of the supply and demand of the crude oil is imperative and to enhance the investment of heavu oil exploration and development(E&D) is the consensus for many petroleum companys.At present,most of the heavy oil is super heavy oil or ultra heavu oil ,how to improve the ultimate recovery is already the main problem.Superheated steam injection is a development maner which can reduce the heat loss from the wellboreto the formation ,can improve the sandface steam quality ,can expand the heating range in the reservoir and can further enrich the steam stimulation technology ,and is a effective way to develop the ultra heavy oil reservoir.This paper study the mechanism of the strengthening recovery for superheated steam firstly,and then esteblish presssure drop and heat loss caculation model considering the fluid phase chaging during superheated steam injection which is base on the mass conservation equation,momentum conservation equation,energy conservation equation,and analyze the influence of the tubing and casing size and hot point on the caculation of the overall heat transfer coefficient ,and according the practical experience,fix the caculation formula of the overall heattransfer coefficient,and the vadility of the caculation model is vadilated by comparing the result of the different state steam,and meanwhile analyze the effect of the wellhead steam injection parameters on the sandface thermal parameters.Secondly,we draw the curve of the dimesional tempreture and the dimensional time and the dimensional distance ,and derivation of the heatloss from the reservoir to the cap and base rock is present when the heat area is incresing as the time's n power,and caculate the heat accumulated value near the steam front,and study the influnce of the latent heat on the caculation of the heating area and heat efficiency.Thidly,this paper establish mathematical model of heat transfer in the multilayer reservoir,and we get the heat distribution curve by conputer programming,and research the effect of the thickness and the thermal physics of the intervening center layer on the thermal interaction between nearby layers.Finaly,this paper gadually caculate the element thermal efficiency of the systerm by analytical calculation,and emphatically analyze the effect of the overheat tempreture and steam injection rate and reservoir and injection time on the thermal efficiency,and use the neural network method to determine the non-linear relationshiop betwee the factors and the heat efficiency which can predict the wellbore and reservoir systerm thermal efficiency.The study on wellbore and reservoir heat transfer during superheated steam injection is the basis of the feasibility study of the superheated steam injection.