EFFECTS OF PETROPHYSICAL ,E NVIRONMENTAL, AND GEOMETRICAL PARAMETERS ON MULTI-COMPONENT INDUCTION MEASUREMENTS ACQUIRED IN HIGH-ANGLE WELLS

This paper describes a numerical study examining the effects of petrophysical, environmental, and geometrical parameters on multi-component electromagnetic (EM) induction logging measurements. Coaxial and coplanar measurements enable the estimation of resistivities parallel and perpendicular to reservoir layers. However, borehole, geometrical, environmental and petrophysical effects can significantly bias these measurements. Understanding such biasing effects will aid in the interpretation of induction measurements and subsequently provide a more accurate and reliable formation evaluation via inversion. We perform numerical simulations of multi-component induction logging measurements with a 3D finitedifference modeling code. A suite of models is considered, including a layered reservoir with varyiable conditions such as borehole dip angle, invasion, and electrical anisotropy. Analysis is carried further to examine the sensitivity of the multi-component measurements to the extent of the invasion zone in a deviated well and in the presence of shoulder-bed anisotropy. Finally, we examine the response due to non-uniform invasion, generated from mud-filtrate invasion in a horizontal well. Simulations show that shoulder-bed effects across sand layers become substantial in the presence of shoulderbed anisotropy, even at low values of dip angle. Measurements centered about sand layers exhibit sensitivity to the depth of mud-filtrate invasion. In particular, coplanar measurements exhibit different responses for symmetric and non-symmetric invasion fronts, indicating the potential ability of multi-component tools to detect non-uniform invasion. In addition, shoulder-bed anisotropy has a considerable effect on these sensitivities, to significantly alter the assessment of invasion in terms of resistivity, depth, and front shape.