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ÖgeNumerical simulation of transient sandface and wellbore temperature behaviors of wells in multilayer single-phase oil and geothermal reservoirs(Lisansüstü Eğitim Enstitüsü, 2022) Alan, Cihan ; Çınar, Murat ; 724609 ; Petrol ve Doğal Gaz MühendisliğiThe interpretation of dynamic temperature data acquired during well tests and distributed temperature sensors (DTS) has grown increasingly in the last decade. While research studies are ordinarily based on sandface solutions, actual field measurements are made in the wellbore, generally at a certain distance above the sandface for conventional well tests. There is still a need for further fundamental studies to emphasize the apparent differences between sandface and wellbore temperature responses especially when it comes to history matching and production optimization applications. The objective of this study is to develop and present applications of a two-dimensional (2-D) r-z, fully implicit, single-phase non-isothermal, transient coupled reservoir/wellbore model with a single well located at the center of a cylindrical reservoir. The model accounts for the Joule-Thomson (J-T), isentropic expansion, conduction and convection effects for predicting the transient temperature behavior and computing the wellbore temperature at different gauge depths. In this study, single phase fluid flow of oil or geothermal brine from a fully penetrating vertical or inclined well in an infinite-acting homogeneous reservoir is modeled. The coupled simulator solves mass, momentum, and energy conservation equations simultaneously for both reservoir and wellbore. The functional iteration procedure is used that updates fluid properties based on available correlations as a function of pressure and temperature at a given time step. Comparisons of the developed model for several syntetic cases with a commercial simulator are provided. We identify diagnostic characteristics of temperature transients at gauge locations at the sandface and above the sandface that may arise during a well test, we examine the sensitivity of the model parameters appearing in the coupled non-isothermal reservoir/wellbore model through synthetically generated test data sets and history matched field application. The drawdown and buildup sandface transient temperature data are obtained from the coupled model and used to interpret and analyze temperature transients. In addition to the J-T coefficient of fluid, we show that history matching transient temperature data provides estimates for the skin zone radius and permeability when analyzed jointly with the conventional pressure test analysis (PTA). An investigation on the effect of gauge location on temperature data shows that the early-time response is influenced by the wellbore phenomena while the J-T effects are clearly identified at later times at typical gauge locations up to 100 m above the top of the producing horizon (refers to total pay zone). Logarithmic time derivative of temperature transients is found as a useful diagnostic tool to differentiate the wellbore phenomena from the reservoir response. It is also shown that the temperature transient is more reflective of the properties of the near wellbore region (e.g., skin zone) than the pressure transient. For this reason, analyzing temperature transients together with the pressure transients could add more value to the analysis to better examine near wellbore characteristics. A comprehensive sensitivity study conducted for multi-layer systems by constructing a 2-D (r-z) coupled model indicates beneficial remarks on PLT data. We provide well profile outputs of pressure, temperature, and flow distributions along the wellbore to identify most influential parameters, such as the layer petrophysical properties and the layer thermal parameters. Several examples of regression on temperature and pressure from multi-layer systems are considered for demonstrating the utility of the developed simulator. Due to high number of parameters involved in multi-layer systems, a robust characterization on thermal and rock properties is required to be able to achieve a realistic regression on temperature profiles to compute inflow rates of individual layers.