Estimation of cost effective oil thickness of oil rims developed with horizontal wells

Key words: oil rims, critical production rate, horizontal wells, optimal well spacing.

The paper describes the novel method to estimate cost effective oil thickness for oil rims and oil reservoirs with gas cap. The method is bases on analytic solutions for critical well oil production rate (critical – without production of breakthrough gas) during early regime of vertical displacement and late regime of gravity drainage. Based on the analytic solution, we propose a dimensionless technic and economic parameters that determine optimal, that maximize Net Present Value, well spacing. The dimensionless parameters include oil thickness, permeability, oil density, initial and residual oil saturations, well costs, oil prices. Given optimal well spacing, we propose an analytic criterion of estimation of cost-effective thickness.