1,720,955 research outputs found
Pressure- and rate-transient model for interfering horizontal wells
No full textIncludes bibliographical references.2024 Summer.Multiple fractured horizontal wells (MFHW) are extensively used to enhance hydrocarbon production from ultra-tight unconventional reservoirs by increasing surface area for fluid flow. Hydraulic fracturing creates or rejuvenates the existing network of fractures surrounding the hydraulic fractures and horizontal well and forms a stimulates reservoir volume (SRV) around the well. The combination of the wellbore features, hydraulic fractures, and stimulated and unstimulated reservoir properties complicates fluid dynamics in unconventional reservoirs. In multi-well systems, fluid flow becomes more intricate due to inter-well interference.
Multi-well systems are essential to maximize reservoir drainage. Oil and gas operators often drill multiple wells from a single pad, resulting in close well spacing, or place infill wells, which can disrupt production in both parent and child wells due to spatial and temporal factors, as well as interwell communication between stacked formations. These development decisions, complicated by interwell connectivity, raise practical concerns of optimum well spacing and stimulation strategies.
To address these challenges by covering numerous options of well placement and stimulation and uncertainties increased by the complex reservoir features, there is a need for efficient models capable of providing quick and robust evaluations of reservoir performance. The objective of this dissertation is to develop a multi-well analytical model that accurately represents the complex interactions in systems with interfering MFHWs in both single- and multi-layered unconventional reservoirs. This model is designed for pressure- and rate-transient analysis (PTA/RTA), crucial for determining reservoir properties and predicting well performance. Unlike traditional PTA/RTA diagnostics that assume standalone wells, this model accounts for spatial and temporal variability of interfering wells.
We consider a reservoir sector including a group of horizontal wells. The sector is divided into blocks for a boundary-element approach, which is simplified by incorporating the trilinear flow assumption. The transient flow problem for each block is solved analytically in Laplace domain and coupled with the neighboring blocks through pressure and flux continuity on their mutual boundaries to obtain the wellbore-pressure solutions.
Analytical solutions developed for multi-well systems, both in single and multiple layers, have been verified against existing analytical models and numerical simulations. Pressure and rate responses generated by the models are analyzed to decipher flow regimes, evaluate reservoir and completion characteristics, discuss well and reservoir performances, history-match production and pressure histories, and predict future performances under complex well interference. Field applications demonstrate the use of these models in well pad development and parent-child well configurations. Sensitivity analyses examine the impact of well spacing and stimulation scenarios. These outputs are instrumental in performance prediction and guiding decision-making processes for infill drilling and stimulation strategies.
The model proposed in this dissertation is a proxy model proposed for specific applications of pressure- and rate-transient analysis (PTA and RTA), evaluation of completion and well-placement options, and provide initial guidance for more detailed numerical simulations. Although there have been some attempts in the literature to build analytical or semi-analytical multi-well models in unconventional reservoirs, the assumptions used in their development limit their utility to reservoirs with uniform properties, require fine gridding and small time-steps, or contradict with the moving boundary problem created by the unsynchronized start and stop of production with different rate and pressure schedules. The model proposed in this dissertation is more general, comprehensive, and robust than the existing models
Unconventional Coalbed Methane Reservoirs Characterization Using Magnetic Susceptibility
No full textAbstractThis research describes a study of the magnetic susceptibility (MS) and permeability as a new approach for a non-destructive coalbed methane (CBM) reservoir characterization. Experimental measurements were undertaken in CBM cores from Kazakhstan (Karaganda Basin). The experimental results showed a strong correspondence between measured magnetic susceptibility and permeability of the CBM core samples. Inverse correlation between magnetic susceptibility and permeability is observed. Generally, the high values of MS correspond to low permeability, likewise the low diamagnetic MS relates to high permeability of production zones. In case of fracturing permeability must be recalculated in relation to the degree of fracturing
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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