Transient, sandface temperature solutions for horizontal wells and fractured wells producing dry gas

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Measured, bottom-hole transient temperature has been proven to be a valuable source of information. Similar to transient pressure (i.e. well testing) the temperature can also be used to estimate formation properties like permeability-thickness or to be used for flow rate allocation. Moreover, transient temperature has the unique advantages being sufficiently sensitive to identify the properties of the near-wellbore zone properties and/or the flowing fluid composition.That is why in the past decade, following the introduction of the modern in-well temperature sensing technology, the value of Temperature Transient Analysis (TTA) has been widely recognised and a number of useful solutions and workflows developed and tested, mostly for the vertical wells due to the reduced complexity of their TTA mathematical problem in the radial flow conditions. TTA requires the installation of high--precision, real-time temperature gauges/sensors close to the sandface. They are most frequently found in intelligent wells, the majority of which are either horizontal or highly deviated. Such high deviation well designs introduces the additional complexity to the data analysis, such as a wider range of flow regimes observed or the magnified impact of formation anisotropy on the reservoir response.There are currently very few published TTA solutions for oil producing horizontal wells and none for the horizontal wells producing gas. This work aims to fill this gap by developing analytical and semi-analytical solutions for the transient, sandface temperature of a gas producing horizontal well.This work first develops transient sandface temperature solutions assuming linear flow into a planar sink as a representation of a horizontal well (or a fractured well). Simplified forms of these equations are developed, making the application of TTA easier. Finally, the effects of heat transfer between the formation and the surroundings, and the effects of flow convergence into horizontal wells are considered. The combination of these for TTA in a horizontal gas well when combined with the existing TTA solutions for a liquid producing horizontal well lays the basis for a comprehensive transient analysis framework for multi-phase production, horizontal wells.