Search

Gas lift design and optimization contributes to one of the key focus areas of whole production optimization value chain. There have been numerous methods and best practices which goes into design of a successful Gas Lift well as well as established industry best practices for the optimal operations of wells and network (facilities), but still gas lift designs derived for present or future well conditions, fail to respond to every possible operating scenario and end up multipointing, slugging or sub-optimal orifice injections. Well completion and well Integrity are two other important focus areas which are independent from gas lift design but possess major challenges to any gas lift well. During completion of a gas lift well, traditionally GLM (Gas Lift Mandrels) carrying dummy valves are run in hole, to allow for setting packers and testing the tubing/annulus strings. These dummy valves require numerous slickline operations to be retrieved and replaced with live IPO (Injection Pressure Operated) and orifice valves, to be able to gas lift. Depending on the well completion complexity (depth, deviation) and number of gas lift valves, slickline operations performed via rig or barge may require up to 3-5 field days. Since GLV replacement operation requires the use of kick over tools, they are susceptible to incur heavy NPT's and associated HSE risks (Slickline and wireline operations accounts for major carbon footprints in upstream segment). During gas lift operations, high pressure gas injected into casing possess enormous risks to nearby wells and surface facilities in the event of uncontrolled annulus gas leak from a single barrier envelope. Operating a gas lift well below MAASP (Maximum Allowable Annuus Surface Pressure) remains a challenge in assuring the well is operating within its integral envelope. At times it also leads to deferred production should the well needs suspended production in the event of SAP (Sustainable Annulus Pressure) or workover caused by compromised well integrity. In this technical paper, authors will attempt to provide a holistic view of a successful Gas Lift well design by addressing the challenges raised (as above) in different phases and emphasizing on the design approach and technical solutions which were implemented, and benefits realized in terms of optimal gas lift operations, rig/ barge days and deferred production saved.

Antibiotic resistance (AR) is a significant threat to the health of many worldwide. The emergence of AR has become the main source of morbidity and mortality from infections that would otherwise have been treatable. AR is mainly caused by the inappropriate use of antibiotics. In the United Arab Emirates (UAE), bacterial resistance to antibiotics is escalating due to: a) practice of self-medication with antibiotics among the residents of the UAE; b) the easy procurement of antibiotics from local pharmacies without prescription; and c) expatriates’ importation of antibiotics from their home country. The present study focused on the usage of antibiotics among the population of Ras Al Khaimah. This study surveyed 306 residents of Ras Al Khaimah to understand their knowledge, awareness, attitude, practices, and perceptions on antibiotics usage. The major pharmacies in Ras Al Khaimah were also surveyed to identify whether the policies on dispensing antibiotics are followed. Of the 306 respondents, %49 have practiced self-medication using antibiotics at least once. The study also finds that pharmacies dispense antibiotics without prescription due to customer demand for antibiotics, lack of patients’ time, patients’ needs, lack of medical insurance, and money concerns. In conclusion, this study provides insight into the level of AR awareness and usage among the Ras Al Khaimah population and emphasizes the need to implement best practices at the grassroots level to overcome the crisis.

Pulsed neutron logging is currently the most commonly used technology for cased hole formation saturation analysis, providing data for reservoir monitoring and management. The common pulsed neutron log measurement is the formation capture cross section (Sigma). The data can be logged at a relatively fast logging speed. Water saturation analysis using the Sigma log requires high porosity and known formation water salinity. Errors in the Sigma log interpretation can result from the uncertainties of water salinity values, which usually change, for example, due to mixing of the hypersaline formation brine with the low-salinity injected seawater. Heterogeneity and changes in the carbonate petrophysical properties also play a role in magnifying the magnitude of water salinity changes. Carbon/ oxygen ratio logging (C/O) is salinity-independent and can be applied to overcome the problem, but the physics of the measurement usually require multiple passes with lower logging speeds than Sigma logging. This paper introduces a novel pulsed neutron logging methodology to help overcome the mixed-water salinity problem and produce a reliable water saturation interpretation for updating fluid front maps. First, the pulsed neutron tool was operated in Sigma mode to cover the full target reservoir interval in a single pass. The tool was then switched to the C/O mode with multiple passes for 50ft only at the top of the target reservoir. Monte Carlo modelling was applied to the C/O data to calculate the water saturation. The C/O result was then used with the Sigma log data to inversely calculate the Sigma water using a Sigma-based material balance equation across the same interval. The final water saturation across the full interval was estimated by using the calculated water salinity and the Sigma data. Through the application of the proposed methodology, we successfully measure the target formation saturation information in an acceptable operating time, when compared to conducting the conventional C/O logging across the full interval. The results show that the estimated formation water salinity is close to that value of drilling mud filtrate; the water saturation is slightly lower than that from the openhole resistivity interpretation. This paper introduces how to optimize a pulsed neutron logging program that combines the C/O and Sigma measurements to enhance the offshore operations efficiency, minimize the water saturation interpretation uncertainties, and support future field development planning.

Experimental and clinical data suggest that high-frequency deep brain stimulation (DBS) of different subcortical structures can be used to control or modulate epileptic seizures. Recent studies showed that DBS of the substantia nigra reticulata (SNr) in rats has an anticonvulsant effect on forebrain clonic seizures. The aim of this study was to determine whether DBS of SNr could also suppress tonic epileptic seizures evoked in hindbrain structures. DBS with high frequency often mimics the effects of surgical ablation of a particular area of the brain. However, the optimal parameters of DBS stimulation to induce ablation-like effects on seizures are not well defined. Consequently, in the first experiment we examined the effects of different stimulation frequencies (80, 130, 260 and 390 Hz) on neuronal activation induced in SNr, using c-fos immunocytochemistry. The results showed that the stimulation of the SNr with 80 Hz has no inhibitory effect while stimulation with 130, 260 and 390 Hz produced a remarkable suppressive effect compared with the control unstimulated side. The aim of the second experiment was to determine whether bilateral inhibition of SNr with DBS could suppress tonic seizures induced by electric shock. Statistical analysis showed that the mean tonic seizure scores following SNr stimulation with either 130 or 260 Hz were not significantly different from scores following the application of the electrode without current. The data suggest that DBS of the SNr produces neuronal inhibition but fails to suppress tonic seizures. We conclude, therefore, that DBS of SNr with frequencies used in this study might not be effective for treatment of patients who suffer from tonic epileptic seizures.

Reservoir A is an Upper Jurassic reservoir in offshore Abu Dhabi, composing layers of dense anhydrite and porous mixed lithology of dolomite and limestone. Petrophysical study from multiple wells suggests that the rock quality within the reservoir has significant lateral and vertical variations that can result in different flow capacities. Consequently, it is crucial to identify the rock quality variations and the consequent flow capacity in horizontal wells to optimize development plan, ideally in real-time. However, these lateral and vertical variations are not visible from conventional porosity (density / neutron) logs, making identification of rock quality very challenging. This paper introduces an innovative magnetic resonance (NMR)-based real-time method of permeability prediction and rock typing.Wireline logs including NMR were acquired in a pilot well, providing porosity and extensive T2-based information (permeability index, irreducible and movable fluid volume and porosity partition). Routine core analysis was also available to calibrate the NMR data, achieving a suitable correlation for NMR permeability index calibration in this field. Several rock types could be identified with the Windland R35 technique using porosity and calibrated permeability from NMR. This identification was then validated by rock types from cores. The application of knowledge gained from the study led to advanced reservoir characterization solely based on the NMR log. The process was applied to high-angle and horizontal (HAHZ) wells where the NMR full-spectrum log while drilling was available.Several slanted wells were drilled with a fit-for-purpose logging-while-drilling (LWD) suite including NMR for geo-steering and formation evaluation. The real-time LWD NMR data helped trace a remarkable change of irreducible water level through certain layers, suggesting that the subzones of Reservoir A changed pore geometry and rock type laterally, resulting in variations of flow capacity and reservoir performance.In one example, this method indicated unexpected good rock quality in one of these subzones considering the experience from offset well. Subsequently, the LWD formation-testing tool confirmed the result with mobility measurements, proving the NMR-based methodology was valid.This process normally applies to memory data after drilling, playing a key role in designing completion strategy in a timely manner. The process is also available in real-time while drilling if full NMR data is transmitted to surface, serving as a safer logging-tool for identification of sub-zones with additional valuable information compared to regular porosity tools with chemical radioactive source.