Fuzzy-Based Screening System for Determination of Enhanced Oil Recovery (EOR) Method in Reservoir

The petroleum industry is developing technology to increase oil recovery in reservoirs. One of the technologies used is Enhanced Oil Recovery (EOR). Selecting an EOR method for a specific reservoir condition is one of the most challenging tasks for a reservoir engineer. This study tries to build a fuzzy logic-based screening system to determine the EOR method. It created the system intending to be able to assist in selecting and determining the appropriate EOR method used in the field. There are nine input criteria used to screen the EOR criteria, namely: API Gravity, Oil Saturation, Formation Type, Net Thickness, Viscosity, Permeability, Temperature, Porosity, Depth criteria. The output criteria generated from the calculation of the EOR screening criteria are 14 outputs, namely: CO2 MF Miscible Flooding, CO2 IMMF Immiscible Flooding, HC MF Miscible Flooding, HC IMMF Immiscible Flooding, N2 MF Miscible Flooding, N2 IMMF Immiscible Flooding, WAG MF Miscible Flooding , HC+WAG IMMF Immiscible Flooding, Polymer, ASP, Combustion, Steam, Hot Water, Microbial. In this system, 512 rules are generated to produce 14 different outputs of the EOR method, with Mamdani's Fuzzy Inference reasoning. This fuzzy-based screening system has an accuracy rate of 80.95%, so this system is suitable to be used to assist reservoir engineers in determining the appropriate EOR method to be used according to the conditions in the reservoir. The sensitivity level of the system only reaches 53.1%, while the specificity level reaches 94%.

The Early Quaternary Marine to Terrestrial Transition of the Southeastern Wairarapa, New Zealand

<p>This study examines the final emergence of the southeastern Wairarapa within a sequence stratigraphic framework. New exposures of the Pleistocene marginalmarine Hautotara Formation, and non-marine Te Muna Formation allow facies to be detailed and sequence architecture to be analysed. Cyclicity observed within the facies successions of the Hautotara and Te Muna formations are placed in a series of four motifs. These motifs record 40 kyr glacioeustatic cyclicity superimposed upon the basinward to landward progression of the environments, showing the region shallowing through time. The positions of the top of the Pukenui Limestone and the base of the Hautotara Formation are revised, and are now at the top of the “Pukenui C” - a widespread marker bed, which also removes a historical nomenclatural gap. The recognition of the significance of the coccolith Gephyrocapsa sinuosa within the underlying Pukenui Limestone allows this contact to be dated at 1.73 Ma. The ~1.6 Ma age limit provided by a number of tephra within the lower sediments of the Te Muna Formation allow the ages of the examined formations to be constrained further. The eight 40 ka cycles identified within the Hautotara Formation suggests deposition between 1.73 and 1.42 Ma. The Hautotara - Te Muna Formation is revealed to be diachronous, with the base of the Te Muna Formation type section shown to be much younger, 1.12 Ma, than the 1.58 Ma age of the lower contact observed elsewhere in the region. A series of palaeogeographic reconstructions at 1.73, 1.58 and 1.57 Ma demonstrate how closely related sedimentation patterns are to structural growth, with marginal-marine Hautotara Formation sedimentation persisting in the centre of the study area well after the initiation of Te Muna Formation terrestrial deposition to the north and south of this site.</p>

The Early Quaternary Marine to Terrestrial Transition of the Southeastern Wairarapa, New Zealand

<p>This study examines the final emergence of the southeastern Wairarapa within a sequence stratigraphic framework. New exposures of the Pleistocene marginalmarine Hautotara Formation, and non-marine Te Muna Formation allow facies to be detailed and sequence architecture to be analysed. Cyclicity observed within the facies successions of the Hautotara and Te Muna formations are placed in a series of four motifs. These motifs record 40 kyr glacioeustatic cyclicity superimposed upon the basinward to landward progression of the environments, showing the region shallowing through time. The positions of the top of the Pukenui Limestone and the base of the Hautotara Formation are revised, and are now at the top of the “Pukenui C” - a widespread marker bed, which also removes a historical nomenclatural gap. The recognition of the significance of the coccolith Gephyrocapsa sinuosa within the underlying Pukenui Limestone allows this contact to be dated at 1.73 Ma. The ~1.6 Ma age limit provided by a number of tephra within the lower sediments of the Te Muna Formation allow the ages of the examined formations to be constrained further. The eight 40 ka cycles identified within the Hautotara Formation suggests deposition between 1.73 and 1.42 Ma. The Hautotara - Te Muna Formation is revealed to be diachronous, with the base of the Te Muna Formation type section shown to be much younger, 1.12 Ma, than the 1.58 Ma age of the lower contact observed elsewhere in the region. A series of palaeogeographic reconstructions at 1.73, 1.58 and 1.57 Ma demonstrate how closely related sedimentation patterns are to structural growth, with marginal-marine Hautotara Formation sedimentation persisting in the centre of the study area well after the initiation of Te Muna Formation terrestrial deposition to the north and south of this site.</p>

The study of plants and embryozem soils on the technogenic dumps aimed to the improvement of the monitoring and remediation in industrial zones

In the soil cover of technogenic territories (Usolye-Sibirskoye, Irkutsk Region, Eastern Siberia, Russia) the initial, organo-accumulative, soddy, and humus-accumulative embryozems were identified. The period of soil formation was established: from 20 years (organo-accumulative) to 40 years (humus-accumulative embryozems). The relationship between regenerative successions of vegetation and stages of the soil-forming process was found. Each stage of post-technogenic soil formation (type of embryozem) corresponds to a certain type of plant communities possessing a clear discrepancy in the species composition. The first stage is represented by plant communities comprising few ruderal species on the initial embryozem. The more advanced stage is characterized by complex communities consisting of grasses, shrubs, and trees on the humus-accumulative soil. It has been shown that the humus content determines the degree of natural restoration of biocenotic functions in the post-technogenic ecosystem. Plants-concentrators that can be effectively used in phytoextraction of metals for decontamination of embryozems have been studied. Natural renewal of vegetation and the development of soil-forming processes serve as the best option for the rational use of nature management in comparison with the artificial restoration of natural landscapes in technogenic territories.

Numerical investigation of tubular expansion and swelling elastomers in oil wells

Solid expandable tubular technology and swelling elastomer seals find extensive use in the repair of aging reservoirs. To improve productivity and cost-effectiveness, they have also become an integral part of new developments such as slim wells and completions with reduced or no cementing. This work reports the use of numerical simulation to investigate the joint use of expandable tubulars and swell packers in various petroleum drilling applications. Material properties of steel tubular and five different swelling elastomers are obtained through mechanical testing. Simulations are performed to study the sealing pressure at the elastomer-formation boundary. Different parameters are studied, such as elastomer material, expansion or compression ratio, seal length, seal thickness, tubular end condition, and formation type. Higher values of rubber elasticity, tubular expansion (expansion ratio), and elastomer compression result in higher seal contact pressure. Contact pressure is higher when the elastomer is pressing against wellbore formation as compared to steel outer casing (zero friction vs. friction), and when the formation is assumed to be rigid as compared to elastic or elastic-plastic. Results of this investigation can be used both for performance evaluation and design enhancement of coupled solid-expandable-tubular and swellable-packer applications.

Organogels as nutraceutical carriers: Effect of addition of lecithin, tocopherols, and EPA/DHA on properties of candelilla wax-soybean oil organogels

Organogels are semisolid and 3D systems in which both an organic liquid solvent and other dispersed particles are entrapped. Today there is not much information about the potential of organogels as carriers of lipophilic nutraceuticals. Therefore, in this work, the preparation and characterization of soybean oil-based organogels with candelilla wax (CW) and lecithin, tocopherol, or EPA/DHA were studied. Soybean oil was structured with 0.5, 1.0, 2.0, and 4.0% w/w of CW. In the organogels, the visual appearance, thermal stability, color parameters, microstructure, hardness, and rheological properties were analyzed. Results showed that soybean oil was successfully structured into an array of solid-like organogels varying in concentrations of CW and added nutraceutical compounds. Increasing CW concentration yielded stronger 3D-network gel formation (type 5 or solid organogel). All organogels were stable at 5, 25, and 35°C during the cyclization process. The nutraceuticals affected the color parameters and 3D network structure. Larger crystalline spherulites and a uniform microstructure were observed, especially in organogels formulated with 4.0% w/w of CW and lecithin. In comparison with the control, organogels (4.0% w/w) with tocopherol or EPA/DHA required lower shear stress to flow whereas lecithin required higher shear stress to flow. Texture analysis showed that organogels with nutraceuticals presented higher hardness, this behavior was attributed to the formation of a larger and softer crystal networks. In conclusion, soybean oil-based organogels formulated with lecithin, tocopherol, or EPA/DHA yielded stable organogels with promising properties as nutraceutical carriers.

Sacroiliac Joint Variation in Patients With Ossification of the Posterior Longitudinal Ligament

Study Design: Retrospective Cohort Study. Objectives: Ossification of the posterior longitudinal ligament (OPLL) reveals heterotopic ossification in the spinal ligament. OPLL also tends to ossify ligaments and entheses throughout the body. However, hallmarks of sacroiliac (SI) joint ossification and its variation in OPLL have not been clarified. Here, we investigated the morphological changes in SI joints in individuals with and without OPLL. Methods: We included 240 age- and sex-matched patients (OPLL+, 120; OPLL−, 120) in the study. SI joint variations were classified into 4 types: Type 1, normal or small peripheral bone irregularity; Type 2, subchondral bone sclerosis and osteophyte formation; Type 3, vacuum phenomenon; and Type 4, bridging osteophyte and bony fusion. Type 4 was further divided into 3 subgroups as previously described. Interactions between the ossified spinal region in OPLL and morphological changes in the SI joint were evaluated. Results: SI joint ankylosis occurs more frequently in patients with OPLL (51.7%) than in those without (non-OPLL) (33.3%). The SI joint vacuum phenomenon (49.2%) was the main finding in non-OPLL. SI joint ankylosis in OPLL was characterized by anterior bridging and intra-articular fusion. OPLL patients with multilevel ossification tend to develop degeneration and ankylosis of the SI joints. Conclusions: OPLL conferred a high risk of SI joint ossification compared with non-OPLL, and patients with extensive ossification had a higher rate of SI joint ankylosis. Understanding SI joint variation could help elucidate OPLL etiology and clarify the phenotypic differences in the SI joint between OPLL and other spinal disorders.

Extensive Horizontal Gene Transfer within and between Species of Coagulase-Negative Staphylococcus

Members of the gram-positive bacterial genus Staphylococcus have historically been classified into coagulase-positive Staphylococcus (CoPS) and coagulase-negative Staphylococcus (CoNS) based on the diagnostic presentation of the coagulase protein. Previous studies have noted the importance of horizontal gene transfer (HGT) and recombination in the more well-known CoPS species Staphylococcus aureus, yet little is known of the contributions of these processes in CoNS evolution. In this study, we aimed to elucidate the phylogenetic relationships, genomic characteristics, and frequencies of HGT in CoNS, which are now being recognized as major opportunistic pathogens of humans. We compiled a data set of 1,876 publicly available named CoNS genomes. These can be delineated into 55 species based on allele differences in 462 core genes and variation in accessory gene content. CoNS species are a reservoir of transferrable genes associated with resistance to diverse classes of antimicrobials. We also identified nine types of the mobile genetic element SCCmec, which carries the methicillin resistance determinant mecA. Other frequently transferred genes included those associated with resistance to heavy metals, surface-associated proteins related to virulence and biofilm formation, type VII secretion system, iron capture, recombination, and metabolic enzymes. The highest frequencies of receipt and donation of recombined DNA fragments were observed in Staphylococcus capitis, Staphylococcus caprae, Staphylococcus hominis, Staphylococcus haemolyticus, and members of the Saprophyticus species group. The variable rates of recombination and biases in transfer partners imply that certain CoNS species function as hubs of gene flow and major reservoir of genetic diversity for the entire genus.

Study of Carotid doppler in Patients with ischemic stroke

Introduction: Stroke is one of the major causes of increased morbidity and death. Large-vessel atherosclerosis of intracranial and extra cranial carotid vessels is an important cause of ischemic stroke. This research was undertaken to study the carotid Doppler findings in patients with acute ischemic stroke. Methods: A hospital-based prospective cross-sectional study was conducted from January 2020 till December 2020 in the department of Radio diagnosis and Imaging at Manipal Teaching Hospital, Pokhara, Nepal. Neuro-imaging and carotid Doppler findings in patients with ischemic stroke were studied. Data analysis was done using SPSS 20. Results: The mean age of subjects with ischemic stroke was 64 ± 13.4 years with the majority of cases in the age group of 51-70 years of age with male predominance (M: F= 3: 2). Lacunar infarcts (34.2%) were the most common findings followed by MCA infarct (30%) and ACA infarct (10.8%). Carotid plaques were seen in 43.3% patients. Bilateral ICA atheromatous plaque was seen in 48.1% of patients. Carotid bulb was the common site for plaque formation. Type III plaque was the commonest type. Significant ICA stenosis > 50 % was observed in 24.2% patients. Age >50 years, male sex, smoking, hypertension, diabetes, and hyperlipidemia were important risk factors. Conclusion: Carotid artery Doppler demonstrated atherosclerotic plaques and significant stenosis in patients with ischemic stroke. Increasing age >50 years, male sex, smoking, hypertension, diabetes, and hyperlipidemia were associated with an increased rate of atherosclerosis, carotid stenosis and ischemic stroke.