A Systematic Methodology for Production Modelling of Naturally Fractured Reservoirs Intersected by Horizontal Wells

A systematic methodology for the optimization of hydrocarbon recovery fromnaturally fractured reservoirs using horizontal well technology is presented.The procedure involves a combination of reservoir characterization pressuretransient analysis, inflow performance analysis, production forecasting, andeconomic evaluation. It is observed from a case study that the methodologydeveloped in this paper provides a quantitative means for characterizingnaturally fractured systems, a theoretical basis for understanding thetransient behavior and inflow performance characteristics of a horizontal wellintersecting natural fractures, and a systematic approach for assessing thefeasibility of exploiting a naturally fractured reservoir using horizontal welltechnology.

The development of horizontal well technology appears to provide anefficient alternative for hydrocarbon recovery from naturally fracturedreservoirs, which may otherwise be economically unfeasible for production byconventional vertical drilling technology. An extensive literature reviewindicates that systematic techniques have not become available for the recoveryoptimization of naturally fractured reservoirs by using horizontal drilling.The current industrial practice is still dependent largely on the basicknowledge of fractured systems and on practical experiences for determining theorientation, length and spacing of horizontal wells. To maximize the recoveryfrom naturally fractured reservoirs using horizontal well technology requires:

1. a quantitative characterization of the natural fracture systems so that theproposed horizontal wells will be drilled orthogonally intersecting the naturalfractures

2. appropriate inflow performance equations for a horizontal wellintersecting natural fractures for proper estimations of well productivity; and

3. adequate production forecasting techniques mid economic evaluation modelsfor efficient evaluations of the production performance of naturally fracturedreservoirs.

Once all of the previous problems are solved in satisfactory manneroptimal development schemes, from both an engineering and an economic point ofview, for exploiting a naturally fractured reservoir using horizontal welltechnology can be achieved.