Successful Reservoir Fluid Characterization and Testing While Overcoming the Challenges of Falling Oil Price and a Pandemic: A First for an Integrated Brown Field Alliance Project in Sarawak, Malaysia

A brown field, offshore Sarawak, Malaysia, with multiple sub-layered laminated sands of varied pressure regimes and mobility ranges, was challenged by depletion, low mobility and uncertainty in the current fluid types and contacts. Optimal dynamic fluid characterization and testing techniques comprising both Wireline and Logging While Drilling (LWD) were applied in nine development wells to acquire reliable formation pressure data and collect representative fluid samples including fluid scanning. Some of the latest technologies were deployed during the dual crises of falling oil price and the Covid-19 pandemic. The S-profile wells were drilled using oil-base mud (OBM) with an average deviation of 60 degrees. Formation Pressure While Drilling (FPWD), Fluid Sampling While Drilling (FSWD) and wireline formation testing, and sampling were all utilized allowing appropriate assessment of zones of interest. Various probe types such as Conventional Circular, Reinforced Circular, Elongated, Extra-Elongated and Extended Range Focused were used successfully, ensuring that the right technology was deployed for the right job. Formation pressure and fluid samples were secured in a timely manner to minimize reservoir damage and optimize rig time without jeopardizing the data quality. As a classified crisis due to the pandemic, rather than delaying the operations, a Remote Operations Monitoring and Control Center was set-up in town to aid the limited crew at rig site. A high success rate was achieved in acquiring the latest formation pressure regimes, fluid gradients, scanning and sampling, allowing the best completion strategy to be implemented. With the selection of the appropriate probe type at individual sands, 336 pressure tests were conducted, 44 fluid gradients were established, 27 fluid identification (fluid-id / scanning) pump-outs were performed, and 20 representative formation fluid samples (oil, gas, water) were collected. Amongst the Layer-III, Layer-II and Layer-I sands, Layer-I was tight, with mobility < 1.0 mD/cP. Wireline focused probe sampling provided clean oil samples with 1.4 to-3.7 wt. % OBM filtrate contamination. The water samples collected from Layer-II during FSWD proved to be formation water and not injection water. The wells were thus completed as oil producers. Reliable fluid typing and PVT quality sampling at discrete depths saved rig time and eliminated the requirement of additional runs or services including Drill Stem Testing (DST). This case study has many firsts. It is the first time where latest fluid characterization and testing technologies in both Wireline and LWD were deployed for an alliance project in Malaysia and that too during dual crises of falling oil price and the pandemic aftermath. Overcoming various challenges including limited rig site manpower, there was no delay in completing the highly deviated wells with tight formations in a single drilling campaign and provided rig time savings. For the purpose of this case study, two wells have been discussed. First well used the wireline focused sampling technology and the second used the FSWD technology.

Combination of Synergic Enzymes and Ultrasounds as an Effective Pretreatment Process to Break Microalgal Cell Wall and Enhance Algal Oil Extraction

Microalgal biomass is a sustainable source of bioactive lipids with omega-3 fatty acids. The efficient extraction of neutral and polar lipids from microalgae requires alternative extraction methods, frequently combined with biomass pretreatment. In this work, a combined ultrasound and enzymatic process using commercial enzymes Viscozyme, Celluclast, and Alcalase was optimized as a pretreatment method for Nannochloropsis gaditana, where the Folch method was used for lipid extraction. Significant differences were observed among the used enzymatic pretreatments, combined with ultrasound bath or probe-type sonication. To further optimize this method, ranges of temperatures (35, 45, and 55 °C) and pH (4, 5, and 8) were tested, and enzymes were combined at the best conditions. Subsequently, simultaneous use of three hydrolytic enzymes rendered oil yields of nearly 29%, showing a synergic effect. To compare enzymatic pretreatments, neutral and polar lipids distribution of Nannochloropsis was determined by HPLC–ELSD. The highest polar lipids content was achieved employing ultrasound-assisted enzymatic pretreatment (55 °C and 6 h), whereas the highest glycolipid (44.54%) and PE (2.91%) contents were achieved using Viscozyme versus other enzymes. The method was applied to other microalgae showing the potential of the optimized process as a practical alternative to produce valuable lipids for nutraceutical applications.

Three-Phase Separator Online Measurement and Data Analytics for Fluid Interface and Emulsion Thickness Utilizing a Single Emulsion Watch Profiler

Separators can over the length of field life be exposed to operating conditions outside the set design conditions, which can cause operating issues in terms of separator efficiency, operating expenditures and potential need for frequent maintenance and/or retrofitting new internals. In mature operations with heavy oils, there can be severe issues with Water-in-Oil and Oil-in-Water emulsion layers. In late life operations, enhanced oil recovery (EOR) efforts with polymer injection can also take place to produce more, but at the same time making the separator function in terms of phase separation even more complex. Emulsion thickness and residence time optimization in separators and tanks are key issues in the oil and gas operations. Real-time data of the full level profiling is complicated and has been based on instruments with varying reliability and performance. Operations have been relying on other process parameters and bottle tests. However, in this work, separator profiler utilizing electrical tomography was used for monitoring separator content online, especially fluid interface levels as well as emulsion and foam layer thicknesses. In addition, effect of polymer injection to the wells is investigated. From the single profiler, data for the separator fluid levels, emulsion and foam thicknesses can be derived. The profiler used is a safe-to-use non-radioactive probe-type measurement sensor which is installed through an existing separator nozzle. The actual separator profiler with dimensions 5 cm diameter and 3 m length was installed downstream of the inlet cyclones and the flow distribution baffles in the three-phase separator located at one of the production fields in the Middle East. Water-oil interface, turbulent water-in-oil dispersion band, oil-gas interface and foam layer thickness were monitored continuously for several months with varying flowrates and operation conditions. Later, effect of polymer injection was also investigated. Interface level and layer monitoring results will be given and discussed. The results show that the profiler is highly useful for monitoring the separator fluid distribution online, building a rigid data analytics model over time that can be utilized by the operations to improve and optimize the performance. This paper shares novel information on operational experience of data analytics used for three-phase separators operating in a heavy oil field with polymer injection. The sensor type used is novel to the industry with high robustness and reliability generating multiple data points per second, enabling a highly detailed analytics model generating new possibilities for operational optimization through digitalization. In addition, commissioning and monitoring of the sensor was done remotely during covid-19 shutdown without the need of external personnel entering the field demonstrating remote commissioning and digital oil field concepts.

Fragmentation and defragmentation of strings in type IIA and their holographic duals

We probe type IIA geometries with folded semiclassical strings those encode the strong coupling dynamics associated with long operators in a class of SCFTs pertaining to spacetimes whose dimension vary from 6d down to 2d. We particularly focus on folded string configurations those are extended through stack of flavor Dp (p = 6, 8) branes localized along the internal manifold. Considering some specific examples within the realm of $$ \mathcal{N} $$ N = 2 linear quivers, we show that the associated string spectrum exhibits a pole as the string approaches flavor D6 branes. We identify this as a fragmentation of long operators in the dual $$ \mathcal{N} $$ N = 2 SCFTs. On the other hand, a similar analysis for $$ \mathcal{N} $$ N = (1, 0) SCFTs in 6d as well as $$ \mathcal{N} $$ N = (0, 4) SCFTs in 4d reveals a set of new dispersion relations at strong coupling. Based on semiclassical calculations, we set an argument that explains either of these cases.

Vitrectomy-Assisted Biopsy: An in vitro Study on the Impact of Cut Rate and Probe Size

<b><i>Purpose:</i></b> The aim of this study was to optimize the technique of performing vitrectomy-assisted biopsy of intraocular tumors by comparing the cytohistological findings in specimens obtained with different vitrectomy probes and cut rates. <b><i>Methods:</i></b> Vitrectomy-assisted biopsies were taken from a fresh porcine liver. For each sampling, the vacuum level was 300 mm Hg. The following parameters were compared; cut rate (60, 600 and 6,000 cuts per minute [cpm]), probe type (standard and two-dimensional cutting [TDC]), and probe diameter (23-gauge and 25-gauge). The specimens were assessed by automated whole-slide imaging analysis and conventional light microscopy. <b><i>Results:</i></b> Seventy-two biopsies were analyzed for the number of hepatocytes, total area of tissue fragments, and total stained area of each microscope slide. For all probe types, these parameters were significantly and positively correlated with the cut rate. TDC probes led to significantly higher scores than those of standard probes, independent of the cut rate. There were no significant differences in results when using 23-gauge or 25-gauge standard probes. Light microscopic examination demonstrated well-preserved cells sufficient for cytohistological analyses in all investigated cases. <b><i>Conclusions:</i></b> The higher the cut rate, the larger is the amount of aspirated cellular material. There were no significant differences between 23-gauge and 25-gauge biopsies. Cut rates up to 6,000 cpm did not adversely affect the cytohistological features of the samples.

Microwave Non-Destructive Testing for Delamination Detection in Layered Composite Pipelines

Microwave imaging and defectoscopy are promising techniques for dielectric composite evaluation. Their most significant advantage is their relatively high penetration depth. Another feature worth noting is that traditional methods could not acquire an internal content with such a low impact on both the sample and surrounding environment, including the test operator, compared to other techniques. This paper presents microwave non-destructive and noninvasive methods for quality evaluation of layered composite materials using an open-ended waveguide probe. Pure |S11| parameters only exceptionally give a clear answer about the location of material cracks. Therefore, this makes it necessary to analyze these parameters simultaneously along with several other factors, such as stand-off distance, probe type or wave polarization. The purpose of the work was to find the dependency between the physical state of a layered composite powerplant pipeline and the S-matrix parameters response (reflection and transmission parameters) in a Ku frequency band that has not yet been extensively researched. Lower-frequency measurements broaden the application possibility for thicker composites, mainly because of a higher penetration depth and measurement setup availability. Different methods have been shown, including reflection and transmission/reflection methods, both in close proximity and in stand-off distance. The measurements are based on a low-complexity experimental setup.

Recovery of Bioactive Compounds from Industrial Exhausted Olive Pomace through Ultrasound-Assisted Extraction

Exhausted olive pomace (EOP) is the main agro-industrial waste of the olive pomace extracting industries. It contains phenolic compounds and mannitol, so the extraction of these bioactive compounds should be considered as a first valorization step, especially if EOP is used as biofuel. Therefore, EOP was subjected to bath-type ultrasound-assisted extraction (UAE), and the effects of the acetone concentration (20–80%, v/v), solid load (2–15%, w/v), and extraction time (10–60 min) on the extraction of antioxidant compounds were evaluated according to a Box–Behnken experimental design. By means of the response surface methodology, the optimum conditions were obtained: 40% acetone, 8.6% solids, and 43 min. For all the extracts, the total phenolic content (TPC), flavonoid content (TFC), and antioxidant activity (DPPH, ABTS, and FRAP) were determined. With the aim of shortening the extraction time, a two-level factorial experiment design was also carried out using a probe-type UAE, keeping the solid load at 8.6% (w/v) and the acetone concentration at 40% (v/v), while the amplitude (30–70%) and the extraction time (2–12 min) were varied to maximize the aforementioned parameters. Finally, a maximum of phenolic compounds was reached (45.41 mg GAE/g EOP) at 12 min and 70% amplitude. It was comparable to that value obtained in the ultrasonic bath (42.05 mg GAE/g EOP), but, remarkably, the extraction time was shortened, which translates into lower costs at industrial scale. Moreover, the bioactive compound hydroxytyrosol was found to be the major phenolic compound in the extract, i.e., 5.16 mg/g EOP (bath-type UAE) and 4.96 mg/g EOP (probe-type UAE). Other minor phenolic compounds could be detected by capillary zone electrophoresis and liquid-chromatography–mass spectrometry. The sugar alcohol mannitol, another bioactive compound, was also found in the extract, and its content was determined. Thus, the use of this technology can support the valorization of this waste to obtain bioactive compounds, including mannitol, hydroxytyrosol, and other derivatives, before being applied for other uses.