Theoretical Research On Temperature Well Test Of Naturally Fractured Reservoir

In the process of oil and gas development,pressure well test is one of the effective means to get the dynamic parameters of strata.At present,pressure data is widely used in well test.Because of many similarities between temperature and pressure.The theory of temperature well testing is also of high value.On one hand,temperature data can be full used in the well test data.In addition,in the well testing interpretation and reservoir evaluation,it can make up for the inadequacy of the interference factors of the pressure well test.However,there is little research on the temperature well test in natural-fractured reservoirs at home and abroad and its theory is not yet mature.Therefore,on the basis of previous studies of temperature well test,deep research can be carried out on the naturally fractured reservoirs.The main work in the paper includes the following aspects.(1)Aiming at the vertical wells in naturally fractured reservoir,on the basis mass-conservation equation,energy-conservation equation and momentum conservation equation,and Joule-Thompson coefficient and comprehensive heat transfer coefficient are taken into consideration,the theoretical model of dual-medium reservoir temperature well test of two models is derived,which respectively are with and without the consideration of pressure field,with the use of Laplace transform and Chain Rules.(2)According to the deduced reservoir temperature approximate solution,the VB programsare respectively complied.The typical temperature curves of the natural fractured reservoir are drawn.Sensitivity analysis of 4 parameters including Peclet Number,heat conductivity ratio,thermal-capacity ratio and permeability ratio are conducted.At the same time,it is found that the normalized dimensionless temperature characteristic curve has a high similarity with the dimensionless pressure characteristic curve.In the normalized temperature semi-logarithmic curve,there are two parallel lines which the slope of 1/2.The slope of the transition period is equal to 1/4,and the size of the concave is determined by the thermal storage capacity.(3)These two models are compared and verified by two exampled wells,and oil production,thermal conductivity and thermal storage parameters are explained by matching the theoretical curves.According to the contrast results,the temperature well testing theory model with consideration of pressure field has better accuracy and better interpretation results.On the basis of the theory of temperature well testing existed,this paper studies the temperature characteristics of double-medium reservoir in naturally fractured reservoir,which plays an important role in the precise reservoir description of this kind of reservoir.