Optimizing the branch number and branch length of radial drilling in high water cut low permeability reservoirs

Abstract

Radial drilling, also called ultra-short horizontal well, is a new kind stimulation technology, which can be used both in new and old wells to improve the productivity and oil recovery effectively. For the low permeability reservoirs, it had been widely used in practice to effectively solve the unbalanced displacement problems for the waterflooded reservoirs. Applying the multi-layer equilibrium displacement principle, the model of optimizing the radial drilling branch number and length for the high water cut low permeability reservoirs is established, and the corresponding programs are also compiled. Using the reservoir numerical simulation technology, this model is proved to be valid and accurate. This optimization method has been applied in Bonan fifth reservoir of Shengli oilfield, which exhibits quite positive results: higher average production rate and lower average water cut of the radial drilled wells. Keywords Radial drilling Á High water cut Á Low permeability Á Equilibrium displacement Well radius r wh Radius of the lateral well S we Water saturation of the exit end S we The average water saturation when the exit end's water saturation is S we l Viscosity of the fluid l o Oil viscosity l w Water viscosity

Simultaneous Evaluation of Time-Dependent Phase and Wetting Properties of Hydrocarbon Liquids for CO2-Enhanced Recovery of Oil and Gas from Tight Reservoirs

“…Below the miscibility pressure, CO 2 could still dissolve in oil and cause volume expansion and viscosity reduction, which help mobilize the oil (see, e.g., refs and ). However, for high-water-saturated tight reservoirs that are frequently encountered, − injected CO 2 would not contact oil freely as a result of the water barrier. As a result, a single-phase condition would not be achieved and dissolution of CO 2 into the oil would not take place directly.…”