Haavard Aakre

Smart Well With Autonomous Inflow Control Valve Technology

A smart well concept with autonomous inflow control valve (AICV) is presented. AICV utilized the best from smart wells (ICV) and inflow control devices (ICD). The technology is presented, discussed and compared against other conventional inflow control technologies, id est (i.e.) passive ICD. The flow characteristics are presented and implemented in reservoir model simulations. Significant increased production and recovery are shown for the application in a thin oil rim with gas cap and heterogeneous reservoir. The AICVs are autonomous, i.e. self-regulating and do not required any external control or force. This makes them simple and robust, and a large number of control valves can be mounted in the well, i.e. one in each screen. When water and/or gas breakthrough occur the valves in the breakthrough zone will autonomously shut-off. This provides the operator with a significantly more efficient production and increased recovery. The AICV technology also enables opportunities to drill longer wells and achieve maximum reservoir contact of each well. In addition, the AICV removes the risk, cost and requirement for separation, transportation and handling of unwanted fluid. Introduction Traditionally, oil reservoirs were accessed by drilling vertical wells. This is simple and straight-forward technique, but with limited reservoir contact per well. Therefore, in order to access more reservoir contact, techniques and devices have been developed to drill horizontal wells, i.e. turning the well from vertical to horizontal oriented [1]. Multi-lateral wells have been installed by several oil companies to maximize the reservoir contact. A major challenge in oil production is to maximize the oil recovery of the reservoir. Today, only a limited part of the oil in a given reservoir is actually recovered and produced before the field is shut down. There are strong incentives for developing new technology in order to increase oil production and recovery. Two factors are of particular importance in order to increase production and recovery from a reservoir: • Obtaining maximum reservoir contact • Preventing negative effects of gas and/or water breakthrough Good reservoir contact may be achieved by drilling long horizontal and/or multi-lateral wells. The pressure drop inside the well is caused by the fluid friction within the pipe, and is proportional to flow rate, fluid density, diameter and length of the well. Hence, longer wells give increased pressure drop, and increased pressure difference between the toe and heel section of the well. This creates non-uniform oil production along the well and results in an early breakthrough in the heel section, as indicated in Figure 1. Permeability differences or heterogeneities along the well may also result in early breakthrough [2] in some parts of the well. The negative effects of breakthrough may be delayed by ICD, [3]. Well completion with ICDs consists of a large number of ICDs disposed at regular intervals along its entire length. The ICDs causes a flow restriction of the fluid flowing from the reservoir and into the well, and will make the inflow profile more uniform. The ICDs are ports having a fixed flow area. The result is a significant increase in the recovery compared with wells without ICDs [3].