| Abstract |
The drilling of the Wells is a direct alternative for verifying the hypotheses formulated from geochemical, geological and geophysical surveys developed during exploration stage of a field. The target of the well drilling is to achieve reservoir and identify firstly, its main physical characteristics such as formation thickness with the seal cap and basement, its permeability, porosity. Nevertheless, even though thermodynamic characteristics are the main objective be achieved in a geothermal well; it is important emphasize that combination with the physical rock properties, adds for obtaining successful results. Due that drilling represents an important possibility for knowing reservoir characteristics it is required a specific and continuous monitoring of each parameter associated to reservoir response. Among others, these parameters are: Rate of penetration (ROP) during drilling, input and output temperatures of drilling fluid, lithology definition from analysis of cutting samples rock formation, fluid circulation losses, temperature and pressure log series and in some cases chemical sampling of fluid drilling. Combination of permeability (identified from high fluid circulation losses) associated with its lithologic formation and high temperature provides a technical support for deciding the drilling stop and analyze formation conditions. In this stage, are programming log series of temperature-pressure at different repose time and transient well test, whose results allow to take decisions on drilling continuity or initiate well completion. Thermodynamic log series allow determine static rock formation temperature, its heating intervals, profile of indices heating and combined with transient pressure test to design the appropriate well completion and arrangement of slotted liners or without slots. In this paper are shown cases of geothermal wells where was applied this methodology helping to take decisions on the thickness or thicknesses selection be exploited in the well, with its corresponding completion design. |