Academic literature on the topic 'EA heterogeneity'
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Journal articles on the topic "EA heterogeneity"
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Helou, C. M., and J. Marchetti. "Morphological heterogeneity of renal glomerular arterioles and distinct [Ca2+]i responses to ANG II." American Journal of Physiology-Renal Physiology 273, no. 1 (July 1, 1997): F84—F96. http://dx.doi.org/10.1152/ajprenal.1997.273.1.f84.
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The present study compares cytosolic calcium concentration ([Ca2+]i) responses to angiotensin II (ANG II) of afferent (AA) and efferent arterioles (EA) by taking account of the localization and morphological differences of EA. In outer cortex, 1 nM ANG II induced smaller [Ca2+]i increases in thin EA than in AA[48 +/- 10 (n = 12) vs. 94 +/- 7 nM (n = 11); P < 0.001]. In inner cortex, two types of EA were considered, i.e., thin and muscular ones. The response to 1 nM ANG II was 35% lower in thin than in muscular EA (P < 0.05) but did not differ from that obtained with corresponding AA. In EA of the outer cortex, 1 microM nifedipine, a dihydropyridine blocker of voltage-operated channels (VOCC), did not affect calcium influx, which was suppressed by 1 mM NiCl2, a nonselective calcium entry blocker. In other arterioles, nifedipine inhibited by approximately 40% calcium entry, and remaining influx was blocked by NiCl2. These results indicate a relationship between the magnitude of [Ca2+]i responses, activation of dihydropyridine-sensitive VOCC by ANG II, and the muscular morphology in renal glomerular arterioles. They suggest that ANG II regulates differently local renal microcirculation. They do not, however, support the hypothesis of a greater sensitivity to ANG II of EA compared with the AA of a given nephron.
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Lisha, Nadra Erin, Adam M. Leventhal, Luanne Rohrbach, Donna Spruijt-Metz, Ping Sun, and Steve Sussman. "The relationship of emerging adulthood trajectories to drug use, and other correlates." Health and Addictions/Salud y Drogas 15, no. 2 (July 30, 2015): 91–102. http://dx.doi.org/10.21134/haaj.v15i2.235.
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Interest in “Emerging Adulthood” (EA) as a unique developmental period has increased. This study examined the heterogeneity of EA among at-risk youth (N=1,677) by identifying trajectories of development across individuals. First, an 8-item version of the Inventory of Dimensions of EA (IDEA) measure was tested for factorial invariance across three time points; the 5-item EA measure was found to be factorially invariant. Next, latent class growth modeling identified three unique developmental trajectories. Lastly, classes were compared on demographics and health-risk behaviors. Class 1 represented a large, low-risk class (highest on EA). Classes 2 and 3 were comparably sized (~5% of the sample). Class 2 appears to be a high-risk class that decreases in EA, while Class 3 appears to be a medium-risk class that increases in EA. This study confirms that not everyone experiences EA similarly and that continuation high school students do not circumvent EA (move directly to adulthood).
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Chen, Min’an, Sisi Zhao, Yu Guo, Luxi Cao, Hai Zeng, Zhuowen Lin, Shiqi Wang, Yimin Zhang, and Mingmin Zhu. "The Influence of Acupuncture Parameters on Efficacy and the Possible Use of Acupuncture in Combination with or as a Substitute for Drug Therapy in Patients with Ulcerative Colitis." Evidence-Based Complementary and Alternative Medicine 2022 (March 22, 2022): 1–16. http://dx.doi.org/10.1155/2022/8362892.
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Background. Ulcerative colitis (UC) is an inflammatory disease of the colonic mucosa, which is accompanied by chronic, idiopathic characteristics. Acupuncture may be an effective therapy for UC. Here we focused on manual acupuncture and electroacupuncture (MA/EA), two widely used and studied acupuncture interventions, to probe the effects of acupuncture parameters on clinical efficacy in patients with UC and the use of MA/EA alone or with other drugs to support their wider adoption in clinical practice. Methods. The PubMed, Cochrane Library, Web of Science, Embase, China National Knowledge Infrastructure Database, and Wanfang databases were searched from inception to April 27, 2021. Randomized clinical trials (RCTs) published in Chinese or English were included, and subgroup analyses were performed according to acupuncture parameter, acupuncture type, and control medicine type. The risk of bias was assessed using the Cochrane Risk of Bias tool and modified Jadad scale, and Review Manager 5.4 and Stata 14.0 were used to perform a meta-analysis. Sources of heterogeneity were explored; sensitivity analysis was performed; and the GRADE methodology was used to assess the evidence level. Results. Sixteen studies (1454 individuals) were included. Retention of the needle [10–30 minutes (RR 1.18, 95% CI [1.11, 1.26], P < 0.01 ; heterogeneity: χ2 = 6.25, df = 6 ( P = 0.40 ), I2 = 4%)], the frequency of MA [once every other day (RR 1.21, 95% CI [1.08, 1.35], P < 0.01 ; heterogeneity: χ2 = 0.80, df = 1 ( P = 0.37 ), I2 = 0%)], and the length of treatment [8 weeks (RR 1.35, 95% CI [1.01, 1.81], P = 0.04 )] improved clinical efficacy at the end of treatment compared with medications alone. MA (RR 1.18, 95% CI [1.11, 1.25], P < 0.01 ; heterogeneity: χ2 = 6.19, df = 7 ( P = 0.52 ), I2 = 0%) increased clinical efficacy compared with medications. Furthermore, MA plus medications (RR 1.26, 95% CI [1.13, 1.40], P < 0.01 ; heterogeneity: χ2 = 0.95, df = 2 ( P = 0.62 ), I2 = 0%) and EA plus medications (RR 1.36, 95% CI [1.13, 1.63], P < 0.01 ; heterogeneity: χ2 = 0.13, df = 1 ( P = 0.72 ), I2 = 0%) both dramatically improved clinical efficacy. The clinical efficacy of MA plus mesalazine or MA plus metronidazole and sulfasalazine was greater than with mesalazine or metronidazole and sulfasalazine alone. Similarly, EA plus sulfasalazine was more effective than sulfasalazine alone. MA/EA resulted in fewer adverse reactions than medical therapies. The use of MA plus medications significantly reduced Baron scores. GRADE evaluations indicated that the evidence strength was moderate to low but mostly low. Conclusions. Our study provides the latest evidence to allow us to speculate about the possible optimal MA parameters to treat patients with UC. The low number of adverse reactions and high efficacy make MA/EA a possible supplement to or replacement for traditional UC drugs. The variable parameter settings preferred by patients and acupuncturists may be an important factor limiting the wider clinical deployment of acupuncture as a potential UC therapy.
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Ayoub, Fares, Tony S. Brar, Debdeep Banerjee, Ali M. Abbas, Yu Wang, Dennis Yang, and Peter V. Draganov. "Laparoscopy-assisted versus enteroscopy-assisted endoscopic retrograde cholangiopancreatography (ERCP) in Roux-en-Y gastric bypass: a meta-analysis." Endoscopy International Open 08, no. 03 (February 21, 2020): E423—E436. http://dx.doi.org/10.1055/a-1070-9132.
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Abstract Background and study aims Endoscopic retrograde cholangiopancreatography (ERCP) is technically challenging in patients with Roux-en-Y gastric bypass (RYGB) anatomy, which is increasing in frequency given the rise of obesity. Laparoscopy-assisted ERCP (LA-ERCP) and enteroscopy-assisted ERCP (EA-ERCP) are distinct approaches with their respective strengths and weaknesses. We conducted a meta-analysis comparing the procedural time, rates of success and adverse events of each method. Patients and methods A search of PubMed, EMBASE and the Cochrane library was performed from inception to October 2018 for studies reporting outcomes of LA or EA-ERCP in patients with RYGB anatomy. Studies using single, double, ‘short’ double-balloon or spiral enteroscopy were included in the EA-ERCP arm. Outcomes of interest included procedural time, papilla identification, papilla cannulation, therapeutic success and adverse events. Therapeutic success was defined as successful completion of the originally intended diagnostic or therapeutic indication for ERCP. Results A total of 3859 studies were initially identified using our search strategy, of which 26 studies met the inclusion criteria. The pooled rate of therapeutic success was significantly higher in LA-ERCP (97.9 %; 95 % CI: 96.7–98.7 %) with little heterogeneity (I2 = 0.0 %) when compared to EA-ERCP (73.2 %; 95 % CI: 62.5–82.6 %) with significant heterogeneity (I2: 80.2 %). Conversely, the pooled rate of adverse events was significantly higher in LA-ERCP (19.0 %; 95 % CI: 12.6–26.4 %) when compared to EA-ERCP (6.5 %; 95% CI: 3.9–9.6 %). The pooled mean procedure time for LA-ERCP was 158.4 minutes (SD ± 20) which was also higher than the mean pooled procedure time for EA-ERCP at 100.5 minutes (SD ± 19.2). Conclusions LA-ERCP is significantly more effective than EA-ERCP in patients with RYGB but is associated with a higher rate of adverse events and longer procedural time.
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Triguero-Martínez, Ana, Emilia Roy-Vallejo, Nuria Montes, Hortensia de la Fuente, Ana María Ortiz, Santos Castañeda, Isidoro González-Álvaro, and Amalia Lamana. "Genetic LGALS1 Variants Are Associated with Heterogeneity in Galectin-1 Serum Levels in Patients with Early Arthritis." International Journal of Molecular Sciences 23, no. 13 (June 28, 2022): 7181. http://dx.doi.org/10.3390/ijms23137181.
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Galectin 1 (Gal1) exerts immunomodulatory effects leading to therapeutic effects in autoimmune animal models. Patients with rheumatoid arthritis have been reported to show higher Gal1 serum levels than the healthy population. Our study aimed to find genetic variants on the Gal1 gene (LGALS1) modulating its expression and/or clinical features in patients with early arthritis (EA). LGALS1 was sequenced in 53 EA patients to characterize all genetic variants. Then, we genotyped rs9622682, rs929039, and rs4820293, which covered the main genetic variation in LGALS1, in 532 EA patients. Gal1 and IL-6 serum levels were measured by ELISA and Gal1 also by western blot (WB) in lymphocytes from patients with specific genotypes. Once disease activity improved with treatment, patients with at least one copy of the minor allele in rs9622682 and rs929039 or those with GG genotype in rs4820293 showed significantly higher Gal1 serum levels (p < 0.05). These genotypic combinations were also associated with higher Gal1 expression in lymphocytes by WB and lower IL-6 serum levels in EA patients. In summary, our study suggests that genetic variants studied in LGALS1 can explain heterogeneity in Gal1 serum levels showing that patients with higher Gal1 levels have lower serum IL-6 levels.
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Heise, Christian, Einas Abou Ali, Dirk Hasenclever, Francesco Auriemma, Aiste Gulla, Sara Regner, Sébastien Gaujoux, and Marcus Hollenbach. "Systematic Review with Meta-Analysis: Endoscopic and Surgical Resection for Ampullary Lesions." Journal of Clinical Medicine 9, no. 11 (November 10, 2020): 3622. http://dx.doi.org/10.3390/jcm9113622.
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Ampullary lesions (ALs) can be treated by endoscopic (EA) or surgical ampullectomy (SA) or pancreaticoduodenectomy (PD). However, EA carries significant risk of incomplete resection while surgical interventions can lead to substantial morbidity. We performed a systematic review and meta-analysis for R0, adverse-events (AEs) and recurrence between EA, SA and PD. Electronic databases were searched from 1990 to 2018. Outcomes were calculated as pooled means using fixed and random-effects models and the Freeman-Tukey-Double-Arcsine-Proportion-model. We identified 59 independent studies. The pooled R0 rate was 76.6% (71.8–81.4%, I2 = 91.38%) for EA, 96.4% (93.6–99.2%, I2 = 37.8%) for SA and 98.9% (98.0–99.7%, I2 = 0%) for PD. AEs were 24.7% (19.8–29.6%, I2 = 86.4%), 28.3% (19.0–37.7%, I2 = 76.8%) and 44.7% (37.9–51.4%, I2 = 0%), respectively. Recurrences were registered in 13.0% (10.2–15.6%, I2 = 91.3%), 9.4% (4.8–14%, I2 = 57.3%) and 14.2% (9.5–18.9%, I2 = 0%). Differences between proportions were significant in R0 for EA compared to SA (p = 0.007) and PD (p = 0.022). AEs were statistically different only between EA and PD (p = 0.049) and recurrence showed no significance for EA/SA or EA/PD. Our data indicate an increased rate of complete resection in surgical interventions accompanied with a higher risk of complications. However, studies showed various sources of bias, limited quality of data and a significant heterogeneity, particularly in EA studies.
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RATNER, Svetlana V., and Andrei O. KOVALEV. "Assessing the regional environmental management system's efficiency based on data envelopment models." Economic Analysis: Theory and Practice 20, no. 6 (June 30, 2021): 1014–42. http://dx.doi.org/10.24891/ea.20.6.1014.
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Subject. The article addresses the eco-efficiency of regional economy. Objectives. The purpose is to design a methodology for assessing the comparative effectiveness of regional environmental management systems, taking into account the significant heterogeneity of regions in terms of eco-efficiency; develop approaches to assessing the eco-efficiency of regional economic systems; integrate these approaches into a single methodology. Methods. The study employs general scientific research methods. Results. The developed approach involves simultaneous solution of two tasks in the data envelopment analysis; one of them is formulated to assess the eco-efficiency of region's economy, and the other – to assess the value for money, aimed at protecting the environment in the region. The solution of these two problems enables to receive a large amount of data that can be used in designing strategies for regional development. Conclusions. The paper offers a new approach to solving the problems of comparative assessment of the effectiveness of regional environmental management systems, considering the structural heterogeneity of regional economies. The findings can be used to elaborate measures to encourage the activities of regional authorities in the field of environmental management and increase their responsibility for the effectiveness of environmental measures.
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Keller, Brett, Dale Rhoda, Caitlin Clary, Claire Rothschild, Mark Conlon, and Paul Bouanchaud. "Bias in product availability estimates from contraceptive outlet surveys: Evidence from the Consumer’s Market for Family Planning (CM4FP) study." PLOS ONE 17, no. 8 (August 30, 2022): e0271896. http://dx.doi.org/10.1371/journal.pone.0271896.
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Area-based sampling approaches designed to capture pharmacies, drug shops, and other non-facility service delivery outlets are critical for accurately measuring the contraceptive service environment in contexts of increasing de-medicalization of contraceptive commodities and services. Evidence from other disciplines has demonstrated area-based estimates may be biased if there is spatial heterogeneity in product distribution, but this bias has not yet been assessed in the context of contraceptive supply estimates. The Consumer’s Marker for Family Planning (CM4FP) study conducted censuses and product audits of contraceptive outlets across 12 study sites and 2–3 rounds of quarterly data collection in Kenya, Nigeria, and Uganda. We assessed bias in estimates of contraceptive product availability by comparing estimates from simulations of area-based sampling approaches with census counts among all audited facilities for each study site and round of data collection. We found evidence of bias in estimates of contraceptive availability generated from simulated area-based sampling. Within specific study sites and rounds, we observed biased sampling estimates for several but not all contraceptive method types, with bias more likely to occur in sites with heterogeneity in both spatial distribution of outlets and product availability within outlets. In simulations varying size of enumeration areas (EA) and number of outlets sampled per EA, we demonstrated that the likelihood of substantial bias decreases as EA size decreases and as the number of outlets sampled per EA increases. Straightforward approaches such as increasing sample size per EA or applying statistical weights may be used to reduce area-based sampling bias, indicating a pragmatic way forward to improve estimates where design-based sampling is infeasible. Such approaches should be considered in development of improved methods for area-based estimates of contraceptive supply-side environments.
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Wang, Xinwei, Antonio Sánchez Egea, Jie Xu, Xianyu Meng, Zhenlong Wang, Debin Shan, Bin Guo, and Jian Cao. "Current-Induced Ductility Enhancement of a Magnesium Alloy AZ31 in Uniaxial Micro-Tension Below 373 K." Materials 12, no. 1 (December 31, 2018): 111. http://dx.doi.org/10.3390/ma12010111.
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The size effects in metal forming have been found to be crucial in micro-scale plastic deformation or micro-forming processes, which lead to attenuation of the material’s formability due to the increasing heterogeneity of the plastic flow. The use of an electric field during micro-scale plastic deformation has shown to relieve size effects, enhance the material’s formability, modify the microstructure, etc. Consequently, these electric-assisted (EA) micro-forming processes seem to bring many potential benefits that need to be investigated. Accordingly, here we investigated the influence of an electric field on the size effects to describe the fracture behavior in uniaxial micro-tension tests of an AZ31 alloy with various grain sizes. In order to decouple the thermal-mechanical and microstructure changes, room temperature (RT), oven-heated (OH), air-cooled (AC), and EA uniaxial micro-tension tests were conducted. The size effects contribution on the fracture stress and strain showed a similar trend in all the testing configurations. However, the smallest fracture stresses and the largest fracture strains were denoted in the EA configuration. EBSD examination shows that current-induced dynamic recrystallization (DRX) and texture evolution could be negligible under the studied conditions. The kernel average misorientation (KAM) maps give the larger plastic deformation in the EA specimens due to the reduction of plastic micro-heterogeneity. Finally, the fracture morphology indicates that the current-induced ductility enhancement may be attributed to the arrest of micro-crack propagation and the inhibition of void initiation, growth, and coalescence caused by lattice melting and expansion.
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Adam, Klaus, and Junyi Zhu. "Price-Level Changes and the Redistribution of Nominal Wealth across the Euro Area." Journal of the European Economic Association 14, no. 4 (November 26, 2015): 871–906. http://dx.doi.org/10.1111/jeea.12155.
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Abstract We show that unexpected price-level movements generate sizable wealth redistribution in the Euro Area (EA), using sectoral accounts and newly available data from the Household Finance and Consumption Survey. The EA as a whole is a net loser of unexpected price-level decreases, with Italy, Greece, Portugal, and Spain losing most in per capita terms, and Belgium and Malta being net winners. Governments are net losers of deflation, while the household (HH) sector is a net winner in the EA as a whole. HHs in Belgium, Ireland, Malta, and Germany experience the biggest per capita gains, while HHs in Finland and Spain turn out to be net losers. Considerable heterogeneity exists also within the HH sector: relatively young middle class HHs are net losers of deflation, while older and richer HHs are winners. As a result, wealth inequality in the EA increases with unexpected deflation, although in some countries (Austria, Germany, and Malta) inequality decreases due to the presence of relatively few young borrowing HHs. We document that HHs’ inflation exposure varies systematically across countries, with HHs in high-inflation EA countries holding systematically lower nominal exposures.
Dissertations / Theses on the topic "EA heterogeneity"
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CANIZARES, MARTINEZ CARLOS. "Essays on empirical macroeconomics." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2022. http://hdl.handle.net/10281/359807.
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Motivated by the desire to inform macroeconomic policy-makers in order to make decisions, this dissertation consists of a compilation of three essays devoted to three different economic questions using three different econometric methods. In particular, Chapter 1 proposes a Markov-switching model to estimate the probability of being in a state characterized by a housing boom fueled by credit (HBFC). This state can be understood as the one potentially previous to a housing bubble, so that it informs policymakers about a dangerous macrofinancial risk at a time in which it might still be possible to avoid the housing bubble and its likely consequential turmoil. Estimated with US data, such model proved consistency in identifying HBFC preceding housing bubbles as estimated in the literature. Chapter 2 is devoted to a thick modeling tool to forecast residential investment. Housing investment is known to be an important leading indicator of economic activity, so its forecast seems key for policymaking. Estimated with euro area (EA) and EA largest five countries data, this tool proved successful in beating benchmark models, while also highlighting the importance of including building permits in housing investment models. Finally, Chapter 3 estimates the effects of monetary policy shocks in the EA and EA largest four economies by means of a factor-augmented Bayesian VAR model identified by sign and narrative sign restrictions. Results show that such shock has significantly negative effects on euro area economic activity, while also show a high degree of heterogeneity in the euro area countries. Looking forward, the methodologies used in this PhD dissertation have proved to be very flexible, so that they could be applied also to other interesting applications.Motivated by the desire to inform macroeconomic policy-makers in order to make decisions, this dissertation consists of a compilation of three essays devoted to three different economic questions using three different econometric methods. In particular, Chapter 1 proposes a Markov-switching model to estimate the probability of being in a state characterized by a housing boom fueled by credit (HBFC). This state can be understood as the one potentially previous to a housing bubble, so that it informs policymakers about a dangerous macrofinancial risk at a time in which it might still be possible to avoid the housing bubble and its likely consequential turmoil. Estimated with US data, such model proved consistency in identifying HBFC preceding housing bubbles as estimated in the literature. Chapter 2 is devoted to a thick modeling tool to forecast residential investment. Housing investment is known to be an important leading indicator of economic activity, so its forecast seems key for policymaking. Estimated with euro area (EA) and EA largest five countries data, this tool proved successful in beating benchmark models, while also highlighting the importance of including building permits in housing investment models. Finally, Chapter 3 estimates the effects of monetary policy shocks in the EA and EA largest four economies by means of a factor-augmented Bayesian VAR model identified by sign and narrative sign restrictions. Results show that such shock has significantly negative effects on euro area economic activity, while also show a high degree of heterogeneity in the euro area countries. Looking forward, the methodologies used in this PhD dissertation have proved to be very flexible, so that they could be applied also to other interesting applications.
Book chapters on the topic "EA heterogeneity"
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Cardoso, João, Marzieh Bakhshandeh, Daniel Faria, Cátia Pesquita, and José Borbinha. "Ontology-Based Approach for Heterogeneity Analysis of EA Models." In Business Process Management Workshops, 131–42. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-58457-7_10.
Full textConference papers on the topic "EA heterogeneity"
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Kunpitaktakun, Takonporn, Prat Boonyasatphan, Seehapol Utitsan, Khuananong Wongpaet, and Hari Primadi. "Integrated Subsurface Reservoir Characterization to Enhance Geomodeling in the Suphanburi Oil Field, Onshore Thailand." In International Petroleum Technology Conference. IPTC, 2023. http://dx.doi.org/10.2523/iptc-22830-ea.
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Abstract To prolong the field life of The Suphanburi oil field, an additional enhanced oil recovery (EOR) process is required. Dynamic reservoir modeling will need to be performed to maximize the EOR strategy. However, achieving the right result is a challenge as the field has a complex depositional environment and high heterogeneity, resulting in a high uncertainty of the dynamic reservoir model. A new reservoir model is proposed and created. The new model has been purposely built to capture the heterogeneity of the field by incorporating the newly interpreted geological concept of the field, together with quantitative seismic interpretation results. First, the new geological concept is interpreted from well data into "depofacies". The depofacies describe both depositional environment and lithofacies. Next, quantitative seismic interpretation is performed to capture the spatial variation of the reservoir and the predefined facies. Lastly, the reservoir model is built by first generating the depofacies. The reservoir or sandstone is then modeled specifically into each pre-modeled depofacies. As a result, the new reservoir model can better capture reservoir heterogeneity, resulting in a better EOR strategy.
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Zhang, Jianguo, Zhenjia Wang, Yifei Lan, Chenyang Zhao, and Jinhua Liu. "Increasing Working Gas Volume of UGS Based on Low Permeability Lithological Gas Reservoirs." In International Petroleum Technology Conference. IPTC, 2023. http://dx.doi.org/10.2523/iptc-22885-ea.
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Abstract Objectives/Scope A low-permeability lithological reservoir was successfully put into operation in 2015 as a gas storage system. The field S2 Underground Gas Storage (UGS) is located in the Ordos Basin and is primarily alithological trap, with low permeability, high heterogeneity, and no obvious seal boundaries. Based on low permeability, low abundance, low vertical wells productivity, low pressure coefficient, serious skin damage in the bottomhole during drilling and completion, strong heterogeneity and unclear lithological boundaries, low control of injection-withdrawal well patterns, the working gas volume and operating efficiency of S2 UGS underperformed relative to modeled expectations. The technical solutions to improve the working gas volume of S2 USG focused upon: well pattern optimization, well placement, stimulation treatment, infillings, and increasing of operating maximum pressure. The results demonstrate that if reasonable technical solutions are adopted, even poor and low-quality storage reservoirs with low permeability, and strong heterogeneity, can be utilized as natural gas storage targets. This discussion provides an overview of approaches used in the Ordos Basin to make operation of S2 UGS more efficient. The development of this project, particularly regarding the operation processes and the resulting adjustments, are noteworthy. The development of such UGS reservoirs require new insights into the performance criteria which can be applied to other reservoirs in the future.
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Fathi, E., and I. Y. Akkutlu. "Effect of Heterogeneity on Advection-Reaction Problem in Porous Media Using a Stochastic Eulerian Flow Model." In Canadian International Petroleum Conference. Petroleum Society of Canada, 2006. http://dx.doi.org/10.2118/2006-113-ea.
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Hermawan Manuaba, Ida Bagus Gede, Mohammad Jad Kareem, Mustafa Al Mubarak, and Gagok Santoso. "The Borehole Properties Analysist Using Advanced Algorithms and Automatic Inversion." In International Petroleum Technology Conference. IPTC, 2023. http://dx.doi.org/10.2523/iptc-22731-ea.
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Abstract The study is based on multi well analysist drilled side by side in carbonate reservoir using high-resolution resistivity image. The objective is to define reservoir characterization, facies architecture, heterogeneity, and connectivity between two wells that is ready for reservoir modeling. The methods presented in this paper are using an automatic inversion and advanced algorithm to generate matrix conductivity images and curves, histogram, analyses rock texture heterogeneities, quantify fluid filled vugs density from high resolution borehole images, fast extraction of dips (beds, fractures), delineate planar features crossing deviated borehole over long distances, extract fracture traces and statistics. More than 3,000 picks of boundaries and fractures were found in a 3,300 ft horizontal length. Those divided into 6 different categories (Bed Boundary, Conductive Fracture, Discontinuous Conductive Fracture, Resistive Fracture, Litho-Bound Fracture, and Vugular fracture). Using high-definition imaging-while-drilling service provides supreme logging-while-drilling (LWD) imaging for reservoir description, from structural modeling, sedimentology analysis, image-based porosity determination and thin-bed analysis. The presence of heterogeneity in carbonates poses a challenge for the characterization of such rocks. The identification of textural variations advanced techniques in borehole image analysis have been applied and presented good results that determine secondary porosity and litho-facies, and, moreover, delivered new insight into previously established interpretations of the reservoir. The data comparison and validation to other measurement show a significant relationship to bring the value even beyond. By using an automatic inversion, the geological interpretation can be constantly delivered around the clock with higher consistency with the number of feature variation. It has been demonstrated that with the advanced analysis, microelectrical borehole images can provide quantitative measures of important reservoir parameters. Accuracy and consistency have been greatly improved since the introduction of microelectrical borehole image logging and subsequent automatic interpretation workflows.
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Azman, Mohd Fairuz, Tunku Ahmad Farhan Tunku Kamaruddin, Nis Ilyani Mohmad, Luqman Hakim Zulkafli, Khiril Shahreza Salleh, and Rizal Bakar. "Rejuvenating Waterflood Reservoir in a Complex Geological Setting of a Matured Brown Field." In International Petroleum Technology Conference. IPTC, 2023. http://dx.doi.org/10.2523/iptc-23056-ea.
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Abstract Field A consists of multi stacked reservoirs in high geological complexity and heterogeneity setting, with waterflooding has been the secondary drive mechanism for the past two decades. However, in recent years, the field experiencing significant production decline that warrant immediate mitigation plan and action. Therefore, this paper highlights challenges and best practices in rejuvenating water injected reservoir to improve field production by integrating geological re-interpretation, data acquisition and analytical evaluation. The reservoir is defined in deltaic environment with complex fluvial reservoir architecture. Despite no indication of structural trap or compartmentalization, there is significant variation in reservoir performance across the field indicates lateral heterogeneity that is affecting the areal sweep efficiency. Poor production-injection allocation data due to commingled production, aggravated by tubing leaks have hindered for an optimum formulation of waterflood strategy in the past. As part of the mitigation plan, depo-facies definition and stratigraphy boundaries were further refined, guided by well and reservoir pressure performance. Besides, inter-well tracer injection implementation proved to be the game changer - unfolded hydrodynamic connectivity and flow path of injected water understanding, established actual producer and injector pairing, and identified poor or unswept areas. It was supported by comprehensive analytical water injection performance analysis including Hall's Plot, Chan's Plot, Jordan's Plot as part of the routine surveillance activities to trigger any non-conformance. More aggressive well intervention also helped to identify and rectify well issues. As the outcomes, there is opportunity to increase water injection rate by 30% field wide by reactivating idle wells, converting producers to injector, and maximizing the existing injection within the safe fracture limit. The subsurface risks on fracture gradient uncertainty and sweep inefficiency due to water cycling to be mitigated via injectivity test with gradual injection, close monitoring of liquid rate handling at surface, and pattern balancing between injectors and producers. The liquid rate is expected to be restored and sustained nearing the historical peak, hence improve field production and temper the decline. This paper presents the best practices to address the challenges in a matured waterflood reservoirs, considering the complex geology setting. Understanding of the flood pattern from tracer analysis, supplemented by producer-injection performance assessment and well integrity status validation enabled water injection to be ramped up at the right area in strategically and safely manner.
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Bentosa, Elena, Glenn Makechnie, Jaime Rabines, and Yacine Meridji. "Drilling Parameter Based Geomechanical Log Application: A Fracture Stage Selection Case Study in Tight Gas Sand Development Wells." In International Petroleum Technology Conference. IPTC, 2022. http://dx.doi.org/10.2523/iptc-22526-ea.
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Abstract In heterogeneous tight sand formations, horizontal wells encounter intervals deposited under varying depositional environments along the lateral portion of the wellbore between landing point and total depth. Horizontal wells in this study were drilled in tight sands deposited in a marine environment where lateral depositional facies changes are common, and hydraulic fracture stimulation is necessary to achieve economic hydrocarbon extraction due to the relatively low permeability of the formation. Without geomechanical logs currently derived from wireline logging, it is not possible to optimize cluster spacing and placement. This step provides necesary information used to optimize completion design, which is crucial to the ultimate productivity of a well. Due to formation heterogeneity, expensive wireline logs must be collected in order to optimize fracture stimulation or else new methods to estimate these logs must be employed. This paper presents a technique to optimize cluster selection for hydraulic fracturing in unconventional tight gas development horizontal wells without wireline logging by leveraging Measure While Drilling (MWD) Gamma Ray logs and surface drilling parameters together with Artificial Intelegence (AI) algorythms to predict density, compressional and shear slowness logs for use in geomechanical evaluation.
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Tao, Liang, Yin Qi, Meirong Tang, Kai Ye, Deyu Wang, Mirinuer Halifu, and Yuhang Zhao. "A New Approach for Multi-Fractured Horizontal Wells Productivity Prediction in Shale Oil Reservoirs." In International Petroleum Technology Conference. IPTC, 2023. http://dx.doi.org/10.2523/iptc-23019-ea.
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Abstract The continental shale oil reservoirs usually have strong heterogeneity, which make the law of fracture propagation extremely complex, and the quantitative characterization of fracture network swept volume brings great challenges. In this paper, firstly, the grey correlation analysis method is used to calculate the correlation coefficient between different parameters and microseismic monitoring volume (SRV), and the key factors affecting SRV are identified. Secondly, the relationship between key geological engineering parameters and SRV is established by using the method of multiple linear regression, and the relationship is further corrected by productivity numerical simulation method, and the empirical formula for quantitative characterization of fracture network swept volume(FSV) is established. Finally, according to the field production of big data, the fitting chart of the accumulated oil production and the FSV is established, and the production of horizontal well is further predicted according to the fitting formula. The study results shown that the main factors affecting the SRV were fracturing fluid volume, fracture density, brittleness index, pump rate, horizontal stress difference, net pay thickness and proppant amount.The FSV in the study area was positively correlated with the cumulative oil production of the horizontal well. With the increase of the FSV, the accumulated oil production increased at first and then tended to be stable, and the optimal FSV was 760 ~ 850*104m3. The prediction method was verified by the typical platform in the field to be accurate and reliable. It can provide scientific basis for the productivity prediction of horizontal wells in shale oil reservoirs.
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Zulkifli, Nazliah Nazma, Luky Hendraningrat, Norzafirah Razali, Che Nasser Bakri, Suzalina Zainal, and Nor Idah Kechut. "Evaluation of Flow Diverter Chemical to Improve Waterflood Performance as Conformance Control for Heterogeneous Reservoir and High-Temperature Field Application: An Innovative Experimental Design." In International Petroleum Technology Conference. IPTC, 2023. http://dx.doi.org/10.2523/iptc-22752-ea.
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Abstract Water injection fields account for over half of Malaysia’s oil production, with most of these fields at matured waterflooding stage. Low sweep efficiency due to water conformance where reservoir with high heterogeneity might cause premature breakthrough is one of the issues that leads to low oil recovery. In this study, we described the comprehensive experimental analysis to substantiate waterflooding performance in heterogeneous reservoirs by evaluating the flow diversion chemical (FDC) as a water conformance agent at high temperature. Chemical characterization, rheology, particle size analysis, compatibility, and thermal stability were evaluated for FDC according to the prevailing mechanism. Afterward, an experiment to simulate the reservoir environment was conducted to estimate oil incremental and blocking mechanism, in terms of residual resistance factor (RRF) performance in the intended field condition. The test was innovatively set up using commercial outcrop and reservoir native cores in dual-core permeability systems to test high permeability and low permeability porous media at high temperature up to 115°C temperature to mimic the conformance process. Typical single core flooding test are only able to determine the potential of the blockage mechanism by determining the RRF, without the diversion effect to quantify the additional oil recovery from the flow diversion process. The setup uses cylindrical preserved core plug samples with permeability contrast ranges from 100mD to 2 Darcy and tested at 115°C. The customized coreflood design successfully mimicked the conformance process. In our study, the RRF of 186 and cumulative oil recovery of 52% with an incremental oil recovery of >5% was obtained by the FDC injection. The study provides an innovative way in the coreflooding experiment to evaluate the performance of a conformance control agent in a heterogeneous reservoir with high temperatures.
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Yan, Weihe, Cong Zhou, Yuhua Wang, Baoyan Jiang, Bo Liu, Jinlong Wu, Xunqi Liu, Qingzhi Lu, Ronarong Paramatikul, and Dung Doan Thi My. "Understanding the Complicated Fracture Network in a Fractured Granite Reservoir Using the Borehole Image and Geochemical Log, Case Study from Songliao Basin." In International Petroleum Technology Conference. IPTC, 2023. http://dx.doi.org/10.2523/iptc-22987-ea.
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Abstract Granite basement reservoir has become a very important exploration target in Songliao Basin of North-east China. Several exploration gas wells were drilled in the study area, and it shows strong heterogeneity and complexity in reservoir properties. Since it is very difficult to perform accurate formation evaluation in fractured granite reservoir using the conventional open-hole logs, the advanced wireline logging such as borehole resistivity image and geochemical logs were acquired to understand the impact of the fractures on the producibility in the tight granite reservoir. The objective of this research is to understand the complicated natural fracture system in the tight granite reservoir. The high-resolution borehole resistivity image logs could provide abundant information to evaluate the fracture distribution, direction, and intensity. It can also reveal the secondary pores and dissolution enhanced features in the granite basement reservoir. The high-definition spectroscope logs provide significant information for geological description and evaluation of the downhole formations. One parameter "K/Na (potassium/sodium) ratio" was developed to differentiate the composition of the minerals in the formation. It was found that the intervals with high K/Na ratio have higher fracture apertures than other intervals in the case. The reservoir quality is controlled by fracture density and secondary porosity. Different sets of nature fractures have a different angle range or strike, and it will create a complex natural fracture network. The fracture zones with complex fracture network have suffered stronger weathering process than the zones with simple fracture network. The case study shows that the high porosity zone with complex natural fracture network has strong dissolution. The K/Na ratio from geochemical log also have clear anomaly in that zone. It indicates that there has strong chemical weathering process in that zone which has high K/Na ratio than other zones. These zones have complex fractures network and strong dissolution than other zones. Better understanding the controlling factors of the fractured granite reservoir could be helpful for fracturing design and well positioning. The integration of borehole image and geochemical log in the fractured granite reservoir was proven to be effective method in this case study. It could be used as a reference for similar reservoir fracture evaluation.
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Tong, Yanming, Xiaodong Chen, Qinghui Zhang, Chuan Wu, Chenqing Tan, Farun Gao, Ning Guo, Wulin Tan, and Monthathip Kosolpinete. "Unravelling the Mystery of Double Complex Unconventional Reservoirs on Tibetan Plateau by Highly Integrated Geophysical and Geological Modelling." In International Petroleum Technology Conference. IPTC, 2023. http://dx.doi.org/10.2523/iptc-22829-ea.
Full textAbstract:
Abstract The study area belongs to Qaidam Basin of Tibetan Plateau. It has extremely complex structural and sedimentological conditions which seriously hinder in-depth geological understanding and effective exploration and development activities. We solve the problems to a great extent with highly integrated unique geophysical and geological modeling. The solutions mainly included: (1) Continuously improving the quality of seismic image by updating the PSDM cube twice during project execution based on a unique workflow of Coupled Geophysical & Geological Modeling; (2) Adjusting/consolidating seismic structural interpretation, well tops, and structural information on microresistivity images reiteratively to obtain robust structural interpretations; (3) Structural modeling with the method suitable for complex structural background; (4) Property modeling with combined constraints of well data, seismic trend, sedimentary cycle, variogram and geological understanding, such as using element logging interpretation results for Lithofacies, Mineral composition and Porosity models; (5) DFN fracture modeling with fracture statistics from microresistivity images, seismic edge-detection cube, seismic drivers and NFP geomechanical drivers. Not only are the double complex reservoirs effectively characterized, but also many meaningful geological conclusions are reached which in turn could guide more effective E&P activities, including (1) distributions of oil-bearing belts, pools, and high-production wells are all controlled obviously by structural patterns; (2) although the reservoirs belong to a very large lacustrine basin sedimentologically, great heterogeneity still commonly exists, with many local structural highs and lows causing quick variation of microfacies in plan view; (3) source rocks, reservoirs, traps and preservation condition are the key factors for oil abundance; (4) four geological conditions need to be carefully evaluated for any outskirt well design & drilling, etc. Based on the results, measured OOIP of tens of millions of tons has been summitted to the country, a bunch of kiloton-oil exploration wells have been drilled and dozens of optimized development wells have been placed in recent years. We realize "for the first time" in some aspects for effectively characterizing the saline lacustrine thin tight oil reservoirs on tectonically complex Tibetan plateau. This study can be referred to by other geologically complex regions in the industry.