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This paper presents a summary of the deployed Smart Liner- SL equivalent to the Limited Entry Liner- LEL as lower completion for the first time in a sidetracked Gas well, Offshore Abu Dhabi. R-1 is subdivided into several sub-layers, the reservoir properties are characterized by low porosity & low permeability (Tight). Reservoir quality in the Upper part is better in terms of porosity & permeability than the lower part. The gas production is mainly from top part of R-1 reservoir, no contribution from Lower part. In 2017, Data gathering was conducted on well A-1 (Coring, Logging & Pressure Points). Actual Gas production Offset wells are restricted from optimal production due to Well Integrity Sustainable Annulus Pressure, to compensate the restricted aged wells due to Well Integrity, Gas production can be increased to 3 times using SL as a stimulation method.The Smart Liner was selected as a lower completion and as a stimulation method for better flow distribution, improved well performance, effective Acid stimulation, also to ensure hole accessibility, allowing aggressive bullhead stimulation at high rate/pressure and high acid concentration at less time ~ 1.5days/job, in addition to eliminating high risk and high cost Coiled Tubing (CT) intervention for stimulation.The first step was to design the SL Completion Workflow with a representative well trajectory for the selected well to be fed and reservoir properties to be extracted from the dynamic model, and then to create a representative stimulation model utilizing property numerical software with all possible scenarios; open hole that represents PPL and suggested SL compartmentalization and holes distribution based on reservoir parameters along the lateral. Once the well model is created, different scenarios for different completion designs are to be run versus different acid concentrations and volumes till achieving the optimum results from stimulation point of view in addition to formation and facilities limitations. Drilling operations were very challenging; fortunately, we succeed to deploy the SL after final adjustment based on FMI Natural Fractures. The Smart Liner as stimulation has proved to be a cost-effective solution for gas wells comparing to advanced stimulation methods in addition to eliminating the high risk and high cost of the Coiled Tubing (CT) intervention for stimulation a huge savings in well construction with maximizing performance.

ADNOC is progressing with large-scale rig-less high-rate matrix stimulation by deployment of advanced lower completions. A key contribution to future production growth is expected to come from these "Smart Liners" that rely on the principles of the limited-entry technique. The concept is based on a number of small, pre-drilled and unevenly spaced holes which enable an even distribution of acid along the entire reservoir drain to be stimulated. The smart liner incorporates swellable packers to avoid annular flow of acid to preferential zones and to isolate segments with heterogeneities. In this work, we focus on aspects related to planning, design and execution of high-rate matrix-acid stimulation of wells. We demonstrate that short wells need a different design approach compared to extended-reach wells and we provide guidelines on how to achieve the highest achievable pump rate and desired acid volume subject to reservoir, well and equipment constraints. The carbonate reservoirs typically exhibit considerable variation in permeability along the well, hence techniques for production profiling, such as inline tracers, are valuable for assessing the actual stimulation effectiveness. Wormhole penetration for a particular acid system will vary depending on the rock petrophysical properties and the reservoir properties; therefore, a systematic data analytics project is on-going.

Following a premature failure of an ICD liner in a pilot ERD well in a giant Middle East offshore oilfield, a thorough investigation, summarised in a prior paper1, 2, was undertaken to understand the failure mechanism. The conclusion of the failure analysis was that high shear flow from the ICDs accelerated tubing corrosion leading to a complete penetration of the tubing wall in the vicinity of the ICDs. This paper details the subsequent work undertaken to initially review existing ICD designs currently available from the market to deem their suitability to withstand flow induced corrosion. Initial review of current designs led to the need for subsequent development of improved ICD designs, also detailed in this paper, that could withstand flow induced corrosion, as well as accommodate heightened production (400 - 1,600 psi) and stimulation (1,000 - 2,400 psi) differential pressure requirements. In particular the paper will cover the below areas of qualification, with key outcomes: Engineering design review of existing, improved and new ICDsCFD analysis for flow-induced corrosion hotspot identificationIntegrity testing for production and stimulation scenariosFlow performance and minimum back pressure requirement testingErosion testing of the entire ICD assembly For any of the designs to be suitably qualified, they had to systematically and successfully pass the aforementioned five areas, which in summation is believed to be the most in-depth qualification program undertaken in the industry to date. It has also likely developed the most robust ICD designs to date affording the ability to operate under heightened production and stimulation conditions while still providing the required 30 year life for use in a giant Middle East offshore oil field.

The recent industry development of drilling ERD wells with horizontal laterals in the reservoir of 10,000 ft. or more has led to a greater use of passive flow control devices and swell packers to achieve the desired inflow or outflow profiles. Another desire is to perform stimulation treatments of the lateral especially in tight carbonate formations. However, such treatments can create high velocities through the Inflow Control Devices (ICDs) that inevitably leads to high turbulence and wall shear stress in the ICD which can cause severe erosion and corrosion of commonly used materials. There appears to be little experience and associated knowledge on corrosion mitigation to ensure ICD integrity after well stimulation. This paper will attempt to address such concerns through: Discussing and analysing ICD design considerations to avoid high corrosion areas and selection of high alloy materials to resist corrosion. Selection of appropriate acid system and method to prevent corrosion. Laboratory testing of acid formulations under high wall shear conditions as predicted from Computational Fluid Dynamics (CFD) of the ICD design at reservoir conditions. Laboratory measurements of the performance of corrosion protection additives in acid formulations under wall shear conditions. Other possible mitigation efforts to reduce the need for stimulation treatments. Each of these factors presents limitations which either restricts the use of aggressive acid systems or requires alternative acid systems that can lead to increased treatment cost and/or sub-optimal stimulation of the reservoir through the ICDs. This paper discusses one producing company's effort to systematically improve the overall performance of stimulation through ICDs while maintaining the integrity of the lower completion liner.

For the last 30 years, wells in the field have been suffering from medium to high corrosion rates in both near surface and downhole components. Remedial measures had been implemented in order to restore Well Integrity with different techniques. Corrective actions aside, a strong preventive approach is needed to better understand the root causes of such corrosion rates and scenarios where the integrity of specific wells has been seriously compromised due to corrosion problems. Taking a step further and considering the big implications of new projects such as Artificial Islands project, where the company will be drilling & completing over 300 Extended Reach Drilling (ERD) wells, Well Integrity input as a discipline becomes critical in order to ensure previous problems will not be repeated and all lessons learned throughout the years will be wisely taken into consideration when designing a new well to remain integral during its whole expected life. Understanding of the current corrosion mechanisms in the field was the key to find not only solutions, but also, to create an approach aimed to improve the future completion for Island wells in terms of design, materials and many other factors. An extensive multidisciplinary approach was carried out in order to successfully complete a full study in one of the pilot wells completed with Inflow Control Devices (ICDs), which will be analyzed in detail in this paper, covering the following areas: Well design and configurationWell monitoring and performance reviewWell diagnosis and failure investigationPost-Failure modelling and well predictionPreventive/Corrective actions for future wells. Corrosion management and prevention of scale deposits were the two main challenges encountered during this project, which was launched and completed with the main objective of evaluate and optimize the ICD completion design in one Maximum Reservoir Contact (MRC) pilot well in the field, the findings and lessons learnt were used to upgrade the current well design and improve the development plan for the field.

As part of the Islands Project which involves the use of 4 artificial islands to drill & complete over 300 ERD wells in a giant offshore oilfield, several completion designs have been piloted to test & monitor their suitability for the brownfield development. One well design incorporated the use of Inflow Control Devices (ICDs) & swell packers which was ZADCO's first use of such technology in a production well. The technology was installed in the pilot well to test in-flow control along a 10,000ft lateral & to manage future water production. The Paper will cover: The design of the well detailing the ICD configurations & swell packer arrangements providing 15 compartments along the reservoir section, The inflow performance recorded annually along the lateral showing differing results, The outcome of an extensive intervention program in 2013 utilising different logging tools to record internal & external data, live camera to view condition in low water cut well & venturi tool to recover downhole samples that concluded the mechanical failure of ICDs in the heel, The extensive post-failure investigation undertaken such as extensive review of installed ICD design, flow assurance, computational fluid dynamic (CFD) simulations, laboratory testing for different conditions & materials, comparison of modelled with actual data to determine failure mode & The way forward for future ICD installations with initial short term solution & plans for future long term design solutions to give a required 30 year life.

Tapered outside diameter coiled-tubing (TODCT) systems have distinct advantages in ultra-deep wells (30,000-ft range) Introduced in 2004, the TODCT system includes: (1) a modified injector that can handle more than one diameter of tubing and maintain a constant grip on the tubing throughout the length of the TODCT string, (2) an ODT "transition tube" that allows sections of tubing with different ODs to be joined together, (3) well pressure control equipment (i.e., blowout preventer and stripper) with the capability to grip and seal more than one diameter of tubing and also grip and seal the transition tube, and (4) an operator control house that allows remote control of the stripper elements and injector gripper elements to open or close to different diameters of tubing while still maintaining control of well pressures inside the wellbore and grip on the tubing.This paper presents a review of the yard testing completed on the TODCT system equipment and then describes a subsequent field trial conducted onshore in south Texas. The end result is a tested and qualified TODCT system capable of safely running tubing strings into ultra-deep wells.