Wellbore Segmentation using Inflow Control Devices: Design and Optimisation Process

Abstract Inflow Control Devices (ICD) optimize production, delay water influx, eliminate / minimize annular flow, and ensure a uniform inflow along the horizontal wellbore at the cost of a small pressure drop. ICDs have brought promises to the industry’s efforts in horizontal wells inflow profile optimization which contributes to the economic success of horizontal wells. Although the structure of different types of ICD varies from one design to another, the principle is the same - restrict flow, and therefore balance or equalize wellbore pressure drop to achieve an evenly distributed flow profile. In general ICD’s are not adjustable once installed in the well. The location of the device and the relationship between rate and pressure drop are fixed. This makes the design of a well completion and inflow control devices critical for production. Having knowledge of the pressure profile of a horizontal well, the ICD completion can be designed to achieve the required uniform influx. Therefore, the need for pressure profile prediction along horizontal wells’ inflow area is obvious. Reservoir conditions are dynamic during the wells’ life cycle; hence the impact of ICD varies over time. Results to date within one of the onshore fields located in Abu Dhabi showed remarkable improvement in well performance, where gains in oil production with controlled water production have been achieved. Long-term reservoir simulation results also showed considerable recovery increase with ICD’s compared to the open-hole case. The paper provides an integrated analysis method of dynamic inflow and outflow to generate the flow profile of a horizontal well. The additional frictional pressure drop created by inflow control devices is considered. Two conditions that result in production challenges, wellbore pressure drop and breakthrough of undesirable fluids are addressed. The focus will be on when and how water encroachment will hit the horizontal well bore and how inflow control devices will act to optimize production. A simulated example at field conditions will be used to illustrate that it is critical to understand the reservoir conditions and wellbore dynamics together when designing a completion with inflow control devices. Uncertainties in reservoir conditions are considered, and a business case for a passive shut-off ICD is discussed through cumulative oil gain predicted by simulation of different development options and completion design strategy. This paper presents the evaluation and results of ICD technology, and how it is expected to become a game changer in this field development.