Abstract：Under the presuppositions that the influence due to borehole and invaded zone is neglected, and that instrument axis parallels to bedding plane, we estimate laterolog responses of horizontal boreholes in two-layer and three-layer formation models, and draw the corresponding templates. In application, we should take environment-corrected microresistivity as the resistivity of probed farmations, and make borehole and invasion corrections of lateral apparent resistivities in deep and shallow parts. Then we can use the two-layer model template to determine whether the horizontal borehole goes in hydrocarbon reservoir or in water saturated formation, and to know both the distance from equivalent oil-water contact to borehole head and the resistivities of the neighboring formations. Besides, we can use three-layer model template to calculate interbed thickness and the distance to borehole head.
