World'S First Successful Dual String Installation of a Digital Intelligent Artificial Lift DIAL - Interventionless Gas Lift Production Optimization System, Offshore Malaysia

PETRONAS completed well H-X on B field in Malaysia with a digital intelligent artificial lift (DIAL) gas lift production optimization system. This DIAL installation represents the first ever successful installation of the technology in an Offshore well for Dual String production. This paper provides complete details of the installation planning and operational process undertaken to achieve this milestone. DIAL is a unique technology that enhances the efficiency of gas lift production. Downhole monitoring of production parameters informs remote surface-controlled adjustment of gas lift valves. This enables automation of production optimization removing the need for well intervention. This paper focusses on a well completed in November 2020, the fourth well to be installed with the DIAL technology across PETRONAS Assets. The authors will provide details of the well and the installation phases: system design, pre-job preparations, improvements implementation, run in hole and surface hook-up. For each phase, challenges encountered, and lessons learned will be listed together with observed benefits. DIAL introduces a paradigm shift in design, installation and operation of gas lifted wells. This paper will briefly highlight the justifications of this digital technology in comparison with conventional gas lift techniques. It will consider value added from the design stage, through installation operations, to production optimization. This DIAL system installation confirms the ability to be implement the technology in a challenging dual string completion design to enable deeper injection while avoiding interventions on a well with a greater than 60-degree deviation. With remotely operated, non-pressure dependent multi-valve in-well gas lift units, the technology removes the challenges normally associated with gas-injected production operation in a dual completion well – gas robbing and multi-pointing. Despite the additional operational & planning complications due to COVID-19 restrictions, the well was completed with zero NPT and LTI. Once brought online, this DIAL-assisted production well will be remotely monitored and controlled ensuring continuous production optimization, part of PETRONAS’ upstream digitization strategic vision.

Trapezoidal Hesitant Intuitionistic Fuzzy Numbers and Their Applications to Multiple-Criteria Decision Making Problems

In this paper, we introduce an extension theory of the trapezoidal intuitionistic fuzzy numbers under intuitionistic hesitant fuzzy sets called trapezoidal hesitant intuitionistic fuzzy number (THIF-number). This new theory provides very effectively to model uncertainties of some events by several different trapezoidal intuitionistic fuzzy numbers based on the same support set in the set of real numbers R. Also, to demonstrate the application of this theory, a new multi-criteria decision-making(MCDM) method based on THIF-numbers is presented. To do this, we first propose operations of THIF-numbers with properties. We second give score, standard deviation degree, deviation degree of THIF-numbers to compare THIF-numbers. We third develop geometric operators and arithmetic operators of THIF-number. Finally, a numerical example is presented to illustrate the application of the developed method in THIF-numbers.

An Innovative Approach to P&A Barrier Verification and Cement Plug Placement Utilising In-Situ Completion Strings: A Case Study

Traditional evaluation of behind-casing cement bond quality prior to cement plug placement involves removal, storage, transportation, and disposal of the tubing completion string. This paper presents an innovative approach to verifying cement bond and subsequent cement plug placement. This method involves cutting and retrieving part of the completion string and deploying acoustic logging tools into the casing, followed by using the tubing as a cement stinger. The procedure described in this paper first involves plugging and cutting the tubing, followed by partial retrieval of the completion to expose the abandonment horizon, which may be an impermeable shale or salt layer. A radial cement bond log tool is conveyed on wireline out of the tubing cut in order to evaluate the cement bond behind the exposed casing section. The existing cement sheath is assessed in accordance to a cement evaluation criteria to determine suitability as a barrier. A balanced cement plug is pumped utilising the existing completion string rather than a dedicated stinger. The permanent barrier is then verified appropriately based on satisfying key metrics in the pumping operation before hanging off the completion tubing in-hole and progressing with the rest of the abandonment programme. In the case study presented here, the tool string design considered the need to pass completion restrictions, convey through production tubing, and remain centralised with up to 50-degree deviation. Analysis of cement bond log data indicated that bond quality was good and suitable to place an internal cement plug across the abandonment horizon. This satisfied a minimum of 200-ft coverage across the zone of interest. The existing deep-set mechanical plug placed in the tubing prior to tubing cut was utilised as a base for the cement barrier. A 2,000-ft balanced cement plug was successfully set across the zone of interest. The completion tubing was used as a conduit for cement slurry placement, eliminating the usage of a dedicated work string. At the end of displacement, the tubing string was pulled out of hole safely to approximately 500-ft above the top of the cement with the help of controlled-gel progression properties incorporated in the slurry design. Due to existing completion accessories, setting a through-tubing cement plug and tubing rotation is not an option. Expandable cement was pumped to mitigate natural shrinkage and enhance post-set cement expansion to ensure a competent barrier. The cement job objectives were achieved by meeting the cementation execution criteria with no requirement to wait on cement. This provides additional time saving to the well abandonment. The discussed approach has successfully realised a significant rig-time saving of approximately two days on each well. Going forward, the methodology has effectively been applied to multiple wells across the Southern North Sea (SNS).

Comparison of Acorn and Fluted Reamers on Tibial Tunnel Outer Aperture Dimensions in Anterior Cruciate Ligament Reconstruction

The aim of this study was to determine if the type of reamer used in tibial tunnel creation during anterior cruciate ligament (ACL) reconstruction influences the dimensions of the tunnel's outer aperture. Tibial tunnels were created in tibial saw bones by reaming over a guidewire using an 8 mm acorn or fluted reamer in an antegrade manner. Reaming was aimed either in line with the guidewire, or with 10-degree inferior/superior deviation in relation to the wire. The shape and size of the outer aperture of the tibial tunnel were compared between the two reamers. When using the acorn reamer, a 10-degree deviation in relation to the guidewire resulted in minimal change in outer aperture length (mean 13.6 vs. 15.6 mm, p = 0.11) and width (11.6 vs. 11.1 mm, p = 0.51). However, when using the fluted reamer, although the aperture width showed no substantial change with reamer/guidewire deviation (11.4 vs. 11.2 mm, p = 0.71), the mean length almost doubled (14.7 vs. 28.1 mm, p = 0.002). The use of a fluted reamer when reaming the tibial tunnel creates a distal aperture which is inconsistently sized, larger, and of oblong shape compared with an acorn-shaped reamer. This should be taken in consideration when using a fluted reamer for creating the tibial tunnel in ACL reconstruction.

Oblique trajectory angles in robotic stereo-electroencephalography

OBJECTIVETraditional stereo-electroencephalography (sEEG) entails the use of orthogonal trajectories guided by seizure semiology and arteriography. Advances in robotic stereotaxy and computerized neuronavigation have made oblique trajectories more feasible and easier to implement without formal arteriography. Such trajectories provide access to components of seizure networks not readily sampled using orthogonal trajectories. However, the dogma regarding the relative safety and predictability of orthogonal and azimuth-based trajectories persists, given the absence of data regarding the safety and efficacy of oblique sEEG trajectories. In this study, the authors evaluated the relative accuracy and efficacy of both orthogonal and oblique trajectories during robotic implantation of sEEG electrodes to sample seizure networks.METHODSThe authors performed a retrospective analysis of 150 consecutive procedures in 134 patients, accounting for 2040 electrode implantations. Of these, 837 (41%) were implanted via oblique trajectories (defined as an entry angle > 30°). Accuracy was calculated by comparing the deviation of each electrode at the entry and the target point from the planned trajectory using postimplantation imaging.RESULTSThe mean entry and target deviations were 1.57 mm and 1.89 mm for oblique trajectories compared with 1.38 mm and 1.69 mm for orthogonal trajectories, respectively. Entry point deviation was significantly associated with entry angle, but the impact of this relationship was negligible (−0.015-mm deviation per degree). Deviation at the target point was not significantly affected by the entry angle. No hemorrhagic or infectious complications were observed in the entire cohort, further suggesting that these differences were not meaningful in a clinical context. Of the patients who then underwent definitive procedures after sEEG, 69 patients had a minimum of 12 months of follow-up, of whom 58 (84%) achieved an Engel class I or II outcome during a median follow-up of 27 months.CONCLUSIONSThe magnitude of stereotactic errors in this study falls squarely within the range reported in the sEEG literature, which primarily features orthogonal trajectories. The patient outcomes reported in this study suggest that seizure foci are well localized using oblique trajectories. Thus, the selective use of oblique trajectories in the authors’ cohort was associated with excellent safety and efficacy, with no patient incidents, and the findings support the use of oblique trajectories as an effective and safe means of investigating seizure networks.

Geometric recognition methodology of honeycomb structure based on dynamic window

Defect determination is important for guaranteeing the quality of sandwich structure. The present study, a geometric recognition methodology based on dynamic window was constructed for honeycomb structure, by identifying the vertices from given images captured in the manufacturing process. The combination of traversing window, annihilation window, and tracking window was developed to reconstruct the contoured maximums, locate the vertices positions, and determine the cell–node relationships, respectively. Moore boundary tracking was practically used to deal with the problem caused by the edge effect. Based on these, all relevant vertices as well as their relationship of each honeycomb cell can be determined. Afterward, quality assessment of the honeycomb product was carried out in terms of the maximum, the average, and the maximum average degree deviation. Illustrations validate the present methodology well. All these achievements shed a light on design of the consistency, reliability, and homogeneity of high-standard sandwich structure.

On relations between Kirchhoff index, Laplacian energy, Laplacian-energy-like invariant and degree deviation of graphs

Let G be a simple connected graph of order n and size m, vertex degree sequence d1 ? d2 ?...? dn > 0, and let ?1 ? ? 2 ? ... ? ?n-1 > ?n = 0 be the eigenvalues of its Laplacian matrix. Laplacian energy LE, Laplacian-energy-like invariant LEL and Kirchhoff index Kf, are graph invariants defined in terms of Laplacian eigenvalues. These are, respectively, defined as LE(G) = ?n,i=1 |?i-2m/n|, LEL(G) = ?n-1 i=1 ??i and Kf (G) = n ?n-1,i=1 1/?i. A vertex-degree-based topological index referred to as degree deviation is defined as S(G) = ?n,i=1 |di- 2m/n|. Relations between Kf and LE, Kf and LEL, as well as Kf and S are obtained.