Horizontal Well Design Optimization: A Study of the Parameters Affecting the Productivity and Flux Distribution of a Horizontal Well

摘要

With the widespread applications of horizontal wells andits successful performance in the last decade, a number ofrelevant questions has been raised with respect to theoptimization of horizontal well design. Considering the highcosts involved and the technical challenges that are faced bythe industry under various scenarios such as offshoreenvironment, unconsolidated sands and heavy oil production,questions related to the optimization protocols to be followedhave become progressively more important and more difficultto answer. Thus, the task of optimizing horizontal well designrequires an investigation of the parameters that affect theproductivity and ultimately the behavior of both reservoir andhorizontal well domains, as well as the risks and costsinvolved in each alternative.Based on a fully implicit, three-dimensional numericalmodel coupling reservoir and horizontal well flow dynamics, adetailed study of the parameters that affect the behavior offlux distribution and productivity along horizontal wells hasbeen performed. The parameters analyzed includepermeability, initial gas saturation, anisotropy ratio, welllocation, fluid viscosity, flow rate, well length, and welldiameter. A tool that permits to compare and select thepotential options in terms of the gain in productivity peradditional unit of well length and diameter is also introduced.Validation of the numerical model used in this study isperformed using production-logging data and the examples ofresults of the application of the optimization protocoldeveloped are reported for some of the Petrobrasoffshore fields.