[en] The Guidoclast project aims at developing a 'good practice' guide for an optimal and sustainable exploitation of the low temperature geothermal doublet in clastic geologic reservoir. A first document proposes a synthesis of returns on experience of geothermal operations performed in Denmark (3 doublets) and in Netherlands (12 doublets), a synthesis of data related to European geothermal operations, and an identification of good practices related to the design of geothermal doublets, to the performance of drilling works and tests, and to the exploitation of geothermal doublets. The second report recalls the project context and execution, proposes the synthesis of returns on experiences performed in northern Europe, and more precisely presents these good practices for two types of clay-loamy or sandy reservoirs (either less than 1 km deep, or more than 1 km deep), and describes how to elaborate a strategy for an exploitation specific to deep clastic reservoirs