As part of enhanced oil recovery (EOR) strategic objectives to boost oil recovery towards 70% aspiration and demonstrate EOR as an attractive viable option for environmental Carbon Capture, Utilization and Storage (CCUS) applications, various conventional and novel EOR technologies and applications are being screened and studied to ensure meeting mandated objectives. Accordingly, number of EOR pilots and projects have grown substantially over recent years to ensure derisking the full field expansion uncertainties and challenges, especially in such carbonate reservoirs with harsh conditions of temperature (~ 250 F) and salinity (~ 200,000 ppm). Detailed screening study and performance review assessment have been conducted, in which gas and chemical based EOR technologies were identified for targeted reservoirs. The candidate reservoirs have a long history of EOR projects focusing on miscible hydrocarbon gas (HC) as early as 1996, which has supported oil production meeting forecast demand. On the other hand, as part of environmental driven strategy for CCUS and EOR applications, CO2 technology has been successfully progressing as EOR business case full-integrated cycle from pilot to field expansion during 2009-2016. In 2016, Al Reyadah has been launched as a unique commercial- scale CCUS facility in the region, that captures 800,000 tonnes of CO2 annually from Emirate Steel Industries and injects it into oilfields to boost crude recovery. Furthermore, novel EOR technologies have been screened and identified with significant potential added value, that includes SIMGAP, SIWAP, Surfactant, Polymer and others, which are currently under modeling and design phase for implementation within upcoming few years to boost recovery factor towards 70% aspiration. Development and piloting of latest technologies are among the main enablers to ensure fit-for purpose applications, proper planning and optimum design for ultimately maximum revenue economically. This paper presents a big-picture overview of EOR technologies with the focus on some cases, challenges and opportunities for super giant carbonate reservoirs.

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.

Carbonate reservoirs require effective acid stimulation to improve well productivity. For long horizontal wells, a complicating factor has previously been the difficulty of controlling acid placement along the reservoir section. The Smart Liner (SL) concept solves this problem. It consists of a number of small holes spaced in such a way so as to distribute acid evenly along the reservoir interval. Fig. 1 shows a schematic of the concept. Without the need of a coiled tubing, acid is bull-headed at a high rate from surface through the production tubing and enters the liner from the left. The liner does not have to be horizontal but very often is. When acid reaches the first hole, which typically has a diameter of 3–6 mm, the pressure drop across the hole is so large that only a small portion of the acid exits the liner through the hole; the remaining acid continues along the liner until it reaches the next hole where the process is repeated. Appropriate hole spacing ensures that acid is distributed with a given acid coverage (dosage) in barrels of acid per foot of reservoir section. The small cross-sectional area of the holes results in focused acid jetting at velocities often exceeding 20 m/s (65 ft/s). The jetting helps promote wormhole formation leading to substantial productivity enhancement. The hole-spacing design requires dedicated software which must take into consideration constraints pertaining to the reservoir, the well, and the pumping equipment while minimizing operational complexity. The tool should also yield a quick answer to enable the user to optimize the final design post drilling and provide a running tally consisting of the sequence of liner joints to be run in hole. In heterogeneous reservoirs, it is typically required to segment the wellbore with swellable packers to isolate sections with different reservoir pressure and/or fluid mobility, and the SL concept readily accommodates that. Also, since the subsequent stimulation relies on matrix acidization, the tool must ensure that fracturing pressures are not exceeded. The original limited-entry liner (LEL) technique dates to the early 1960s and was proposed for fracturing applications (SPE 530). Reviews by Somanchi et al. (SPE 184834) and Weddle et al. (SPE 189880) suggest that it is still widely applied for such purposes. In the late 1990s, Maersk Oil adapted the concept to effectively stimulate extended-reach wells in its North Sea chalk reservoirs on a large scale. Hansen and Nederveen (SPE 78318) refer to the technology as controlled acid jetting (CAJ). In the following years, the CAJ technique was implemented in more difficult formations such as a 0.1 mD chalk reservoir (SPE 144159) as well as in a tight, gas-bearing formation (SPE 123979). Balsawer et al. (IPTC 17611) designed multizone completions in ultralong wells in a giant field offshore Qatar, which comprised more heterogeneous limestone formations. Other field implementations have been described by Issa et al. (SPE 171779) for a super-giant reservoir offshore Abu Dhabi. Past deployments have concentrated on extended-reach wells with reservoir temperatures up to 210°F. Over the past year, ADNOC has significantly expanded the operational envelope of the Smart Liner concept. Fig. 2 summarizes the variation in completed reservoir length and average permeability for 80 well designs. Table 1 shows that reservoir temperatures vary from 140°F to 300°F.

Since the early days of the petroleum industry, prediction of oil prices has been a real challenge. The puzzling question we need to answer when evaluating project's NCF is: how much is the price of a barrel during the life-span of the project? Accordingly, oil price modeling became a vital tool to predict both short-term and long-term prices. Unfortunately, there are many uncertainties associated with the available models and none of them can predict oil prices with acceptable accuracy. Only limited controlling parameters are captured by these models. These parameters are basic and derived from simple assumptions of supply and demand dependency. Nowadays, the need for a reliable oil price model became more critical as a change of oil price is experiencing dramatic fluctuations that affect economic decision parameters a great deal.This paper presents an oil-price model to project the price behavior in the next 20 years. Different scenarios were examined out of which "Economic-Scenario" was found to be the best suitable predictor. This model takes into account multiple effects of fourteen parameters that are believed to have the highest impacts on oil price. These factors have been further classified into key categories such as supply, demand, reserve and externalities (political/environmental/social) which is regionally based. Other parameters such as population growth and technology are embedded within these key factors. According to this model, oil price has been found to have strong reliance on the US Dollar and inflation, which has been incorporate into the model to ensure a more reliable outcome.Market behavior modeling is a continuous process which is planned to be integrated into the proposed model in the near future once consistent data become available. The major obstacle in modeling market behavior is the lack of futuristic behavior that is primarily dependent on accurate historical data. This data should reflect the performance of short-term effects such as lifestyle, human behavior, politics, conflicts, wars, natural disasters, environmental issues and other economies' behaviors. The ultimate goal of this modeling effort is to assist in economic and risk analysis evaluation of petroleum projects.

A super Giant field production sustainability is essential and has to be sustained for longer period of time, therefore different techniques have been introduced and tested to overcome the various reservoir issues. Gas Lift technique (GL) has been considered as one of the effective mitigation actions to reactive the dead wells, enhance recovery factor (RF) and accelerate the production from both technical and economical points of view. Prior the full field implementation, it was decided to select a GL Pilot for testing and data gathering, the planned GL Pilot consists of 10 wells which have been selected from various reservoir units and completions to analyze the differences in the performance. The selected Pilot wells were inactive prior to GL implementation (with no oil production) as per set strategy which calls for using of the GL system to reactive the dead wells only.The Pilot started production in November 2008 with almost a total oil production rate of 14 Mstb/d using GL system and the current average rates of the pilot (as of Jan. 2010) are as follow: average oil rate ~ 13,000 bbl/d, average water rate of ~ 19,000 bblw/d, average gross rate of 32,000 bbl/d and average W.C% ~ 60%. The pilot performance was achieved with total gas lift injection ~ 6 MMSCFD (which means 0.6 MMSCFD per well in average). The total oil recovered from the current GL pilot, during a period of one year (330 producing days) is 4.15 MM bbl, this can be roughly turned in to cash amount equal to $ 207.5 MM (assuming 50$/bbl).These resulted values from the GL wells have been surging up and down as a result of the optimization process in order to minimize the W.C% and increase the oil rate. Real Time Optimization (RTO) process is important and currently is ongoing (last stage) to be fully implemented to optimize especially the GL produced water (amount and treatment) in addition to the oil production. Gas quality, availability and conditions have been ensured with the current available field facilities.Pilot Modeling is vital to assess each well behavior, therefore every well has been modeled using Inflow/Outflow Software and pertaining data has been continuously validated and updated according to the production tests and actual findings. Different monitoring tools have been used such as RST, PLT and Gas Lift surveys to identify the actual well performance. The Pilot modeling results have been used as a guidance to predict the full field future GL performance.Generally, the Pilot results revealed the important questions and achieved the core objectives related the GL system for full field implementation.