Autonomous Inflow-Control Devices Boost Production While Managing Sand

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 30403, “Sand Production Management While Increasing Oil Production of a Gravel-Packed Well Equipped With Rate-Controlled-Production Autonomous Inflow-Control Devices in a Thin Heavy-Oil Reservoir Offshore China,” by Shuquan Xiong, Fan Li, and Congda Wei, CNOOC, et al., prepared for the 2020 Offshore Technology Conference Asia, originally scheduled to be held in Kuala Lumpur, 2–6 November. The paper has not been peer reviewed. Copyright 2020 Offshore Technology Conference. Reproduced by permission. A 2018 infill development campaign for a horizontal well offshore China targeted improved production through the installation of autonomous inflow-control devices (AICDs). However, because the well requires gravel packing to manage the sand, the integration of AICDs and the gravel pack was an issue. An integrated work flow was followed to deliver the AICD application successfully in an offshore heavy-oil reservoir with major uncertainties in remaining oil thickness and water/oil contacts. AICD completions ensured balanced contribution from all reservoir sections and limited water production significantly while the gravel pack kept the valves safe from the effects of sand. Field Description The field is a low-amplitude fault anticline oil field developed on the basement uplift. The structure is relatively gentle (Fig. 1). The reservoir lithology is mainly feldspathic quartz sandstone, with an average porosity of 22%, an average permeability of 397 md, a reservoir pressure coefficient of 1, an oil density of 0.92 g/cm3, and crude oil viscosity of 150 cp. The current methodology for gravel packing with ICDs/AICDs in the well uses a multiple alpha-wave technique whereby at least one conventional standalone screen joint is deployed at the toe of the well to provide a return path during the buildup of the alpha wave. The flow rate is reduced progressively to maximize the dune weight until screenout is observed. Once the gravel-packing operation is complete, the standalone-screen section at the toe is isolated before the well is placed on production. This technique does not allow a complete pack to be achieved and will allow more gravel to build up around the zonal isolation packers. This methodology is most applicable in unconsolidated sands with high net-to-gross reservoirs where borehole collapse will occur early in well life. One technique to provide sufficient flow path through the screen assembly is to integrate sliding sleeves into each screen joint. However, in long lateral wellbores, this may be prohibitively expensive and requires multiple manual manipulations as the wash pipe is retrieved. The use of a temporary bypass valve is recommended to enable standard gravel-packing operations to be performed with ICDs without significant additional cost, complexity, or compromise. The dissolvable material is used with a valve located within the ICD/AICD housing to provide a high-flow-area path from the annulus to the tubing during completion operations.

Relaxation Degree Analysis Using Frontal Electroencephalogram Under Virtual Reality Relaxation Scenes

Increasing social pressure enhances the psychological burden on individuals, and the severity of depression can no longer be ignored. The characteristics of high immersion and interactivity enhance virtual reality (VR) application in psychological therapy. Many studies have verified the effectiveness of VR relaxation therapy, although a few have performed a quantitative study on relaxation state (R-state). To confirm the effectiveness of VR relaxation and quantitatively assess relaxation, this study confirmed the effectiveness of the VR sightseeing relaxation scenes using subjective emotion scale and objective electroencephalogram (EEG) data from college students. Moreover, some EEG features with significant consistent differences after they watched the VR scenes were detected including the energy ratio of the alpha wave, gamma wave, and differential asymmetry. An R-state regression model was then built using the model stacking method for optimization, of which random forest regression, AdaBoost, gradient boosting (GB), and light GB were adopted as the first level, while linear regression and support vector machine were applied at the second level. The leave-one-subject-out method for cross-validation was used to evaluate the results, where the mean accuracy of the framework achieved 81.46%. The significantly changed features and the R-state model with over 80% accuracy have laid a foundation for further research on relaxation interaction systems. Moreover, the VR relaxation therapy was applied to the clinical treatment of patients with depression and achieved preliminary good results, which might provide a possible method for non-drug treatment of patients with depression.

Airborne protection for staff is associated with reduced hospital-acquired COVID-19 in English NHS Trusts

Introduction Hospital-acquired infection with COVID-19 (HAI) has reduced from 14.3% to 4.2% over the last year, but substantial differences still exist between English NHS trusts. Methods We assessed rates of HAI, comparing trusts using airborne respiratory protection (RPE, eg FFP3 masks) for all staff, as a marker of measures to reduce airborne spread, against those using mostly droplet precautions (eg surgical masks). Results/Discussion RPE use was associated with a 33% reduction in HAI odds in the Delta wave, and 21% in the Alpha wave (p<0.00001). We recommend all hospitals make airborne mitigations a priority.

Quantifying VR cybersickness using EEG

Current techniques for characterizing cybersickness (visually induced motion sickness) in virtual environments rely on qualitative questionnaires. For interactive graphics to create visual experiences that enhance the illusion of presence while mitigating cybersickness, interactive measures are needed to characterize cybersickness. In this paper, we acquire EEG signals from participants as they experience vection-induced cybersickness and compare those signals to a baseline. Our study shows that there is a correlation between the participant-reported cybersickness (as measured by movements of a joystick) and brain EEG signals. Through independent component analysis, we separate those signals which are a result of cybersickness from other sources (such as eye blinks). Our user study finds that there is a highly correlative and statistically significant Delta- (1.0–4.0 Hz), Theta- (4.0–7.0 Hz), and Alpha-wave (7.0–13.0 Hz) increase associated with cybersickness in immersive virtual environments across participants. Establishing a strong correlation between cybersickness and EEG-measured brain activity provides us with the first step toward interactively characterizing and mitigating cybersickness in virtual environments.

Electroencephalographic Correlates of Cognition among Nigerian Women with Epilepsy on Anti-epileptic Monotherapy

Background: The prospect of EEG as a potential biomarker for detecting a cognitive decline in those living with epilepsy has not been extensively studied. Objective: To determine the relationship between electroencephalographic (EEG) changes and cognitive functions in Women with Epilepsy (WWE). Methods: The study involved 100 adult WWE aged between 16 and 40 years on Levetiracetam (LEV) or Carbamazepine (CAB) monotherapy. Zung Self-Reporting Depression Scale (ZSRDS) was used to assess the mood of participants while the Community Screening Interview for Dementia (CSID) was used to assess various cognition domains. Results: The frequency of Periodic Epileptiform Discharges (PED) (p = 0.008), delta waves and theta waves (p = 0.004) were higher in WWE with Cognitive Impairment (CI) compared to those without CI. Lower cognitive scores were seen among those with delta wave across the domains of cognition with statistical significance for language fluency (p = 0.039), language comprehension (p = 0.000), and total CSID (p = 0.000). WWE with PED had a lower mean total CSID score compared to those without PED (p = 0.019). The absence of alpha wave (p = 0.027), presence of delta wave (p = 0.013), slow frequency (p = 0.015) and PED (p = 0.031) were EEG predictors of cognitive impairment. Medication type (p = 0.016) and depression (p = 0.001) were the clinical predictors of cognitive impairment in WWE. Conclusion: The frequencies of PED and slow waves were higher in WWE with CI while the absence of alpha wave, presence of delta wave and PED were EEG predictors of CI.

Changes in the Brain Activity and Visual Performance of Patients with Strabismus and Amblyopia after a Compete Cycle of Light Therapy

This research assesses the brain activity and visual performance at baseline and after light therapy (LTH), of seventeen patients with strabismus and amblyopia (SA), and eleven healthy controls (HCs) from Querétaro, México. Quantitative electroencephalogram analysis (qEEG) was used to record the brain activity, and clinical metrics such as the visual acuity, angle of deviation, phoria state, stereopsis, and visual fields determined the visual performance. Results showed a constant higher alpha-wave frequency for HCs. Low voltages remained negative for HCs and positive for SA patients across stimulation. After LTH, high voltage increased in SA patients, and decreased in HCs. A second spectral peak, (theta-wave), was exclusively recorded in SA patients, at baseline and after LTH. Positive Spearman correlations for alpha-wave frequency, low and high voltages were only seen in SA patients. Synchronized brain activity was recorded in all SA patients stimulated with filters transmitting light in the blue but not in the red spectrum. Enhancement in the visual performance of SA patients was found, whereas deterioration of the phoria state and a decrease in the amount of stereopsis was seen in HCs. To conclude, only a suffering brain and a visual pathway which needs to be enabled can benefit from LTH.