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.

This paper covers a super giant carbonate oilfield in the Middle East that has enjoyed pressure support and voidage maintenance, primarily with peripheral water injection and pattern development in some reservoir units over the last decades. However, premature and non-uniform water front advancement has been a great challenge, resulting in early and uncontrolled water breakthrough with some wells becoming inactive due to increasing watercut. This challenge is mostly attributed to reservoir heterogeneity and particularly to the presence of un-mapped high permeability streaks (greater than 1Darcy) in the carbonate reservoir, usually resulting in by-passed oil and high value of Remaning Oil Saturation with poorer sweep efficiency. As a result, aiming to reach the desired ultimate recovery factor has become a challenge. A multidisciplinary approach involving the integration of various datasets, including geology (core facies and core description), geophysics (seismic stratigraphy), petrophysics (open hole logs, cased hole saturation time-lapse logs, and cased hole production logs), reservoir and production engineering (actual wells performance), and drilling data (mud losses, pilot hole) etc, were used to identify the high permeability streaks aerially and vertically within the reservoir. These high permeability streaks were then tested in the 3D dynamic model with various sensitivities to assess the impact on the reservoir performance in order to improve the match with the actual performance. The preliminary results were further validated by acquiring more data and gaining deeper understanding from Pulse Neutron logs, Injection and Production Logging, Flow tests, Pressure Transient Analysis etc. In order to reactivate inactive wells, increase production performance, and improve the sweep efficiency, targeted water shut-off was carried out to isolate the watered out intervals. Injection and Production logging gave more insights to understanding injection conformance and reservoir performance with adequate measures taken to ensure optimal reservoir management. In addition, areas with by-passed oil were targeted with revised well completion, infill drilling and artificial lift strategies. This paper describes the approach used, challenges encountered, results obtained, and the way forward.

Wellbore instability challenges encountered while drilling the Nahr Umr Shale include, but are not limited to, hole collapse leading to hole enlargement. Wellbore instability leads to huge cost increases in the drilling process and in rare cases well abandonment. Observations from drilling data suggest that wellbore stability varies with different wellbore deviations and azimuths, especially in areas of highly laminated formations and anisotropic in-situ field stresses. Accurate information on the rock strength and rock failure behavior in shale has a major impact on the improvement of drilling efficiency. Knowledge of the mechanical properties of shale is essential to implement any 3D shale anisotropy borehole instability model (Crook AJL, et. al., 2002). Shale mechanical properties were evaluated from laboratory tests. Well-preserved core samples retrieved from the Nahr Umr Shale were put through several tests to describe the mechanical characteristics related to rock strength and in-situ stresses with the aim to determine the effect of the anisotropy and plane of weakness in drilling high-sailing angle trajectories. Strength anisotropy was assessed using the plane of weakness model (Jaeger, J.C., & Cook, N.G.W., 1979) which assumes that the heterogeneous media is composed of a matrix rock and a plane of weakness (e.g., bedding/laminations, interface between lithotypes or laminations). Shear failure occurs once the shear stress acting on the plane of weakness exceeds its shear strength. Laboratory tests include both extremely slow triaxial tests and multistress path testing performed on three orientations. Failure envelopes were created to develop the plane of weakness model to predict the orientation of the weakest plane and determine the magnitude of the strength reduction. Elastic anisotropy data from plugs is combined with advanced sonic logs, enabling a more robust evaluation of the formation anisotropy to improve both stress predictions and the allowable mud-weight windows during wellbore stability assessment.