bluuebunny/crossref_metadata_2025_split huggingface dataset:
The differences of glycodelin and uterus NK cell expression in obese and non-obese rats (Rattus norvegicus)
Authors: Ningtriyas Diyah Nofita Ofa , Wiyasa Arsana , Nooryanto Muhammad 
Published: September 2021

HIGHLIGHTS1. Obesity increases the risk of comorbidities especially for the pregnancy.2. The study analyzed glycodelin levels and uterine NK cell expression using Rattus norvegicus as animal model.3. uNK cell expression of the obese rats group was higher as the marker of chronic inflammation for obesity.4. Although there was increasing uNK cells in obese rats group, this result was not followed by the level of gycodelin.ABSTRACTObjectives: To prove the existence of differences in glycodelin levels and uterine NK cell expression in obese and non-obese female white rats of Wistar strain (Rattus norvegicus).Materials and Methods: . This study used a randomized post-test only controlled group design. This in vivo study used two groups of female rats (Rattus norvegicus). Group 1 was treated with the high obese diet for eight weeks, and group 2 was not treated with the high obese diet. After eight weeks, the rats were weighed, the proestrus phase was synchronized, and then the rats were terminated.Results: In this study, there was no significant difference in glycodelin levels between the obese and non-obese groups with a p= 0.821 (p >0.05). Significant differences were found in uterine NK cell expression between obese dan non-obese groups with p=0.001 (p <0.05). The correlation test of glycodelin levels and uterine NK cell expression showed insignificant results with a correlation coefficient of 0.120 and p=0.513. This proved that there was no significant correlation between glycodelin levels and uterine NK cell expression.Conclusion: There was no significant difference between glycodelin levels and uterine NK cell expression in obese and non-obese female white rats of Wistar strain (Rattus norvegicus).
Continuum-Scale Gas Transport Modeling in Organic Nanoporous Media Based on Pore-Scale Density Distributions
Authors: Liu Zizhong , Emami-Meybodi Hamid 
Published: September 2021

Abstract
We present a continuum-scale diffusion-based model informed by pore-scale data for gas transport in organic nanoporous media. A mass transfer and an adsorption model are developed by considering multiple transport and storage mechanisms, including bulk diffusion and Knudsen diffusion for free phase, surface diffusion and multilayer adsorption for sorbed phase. A diffusion-based governing equation is derived based on free phase concentration for the overall mass conservation of free and sorbed phases, carrying a newly-defined effective diffusion coefficient and a capacity factor to account for multilayer adsorption. Diffusion of free and sorbed phases is coupled through a pore-scale simplified local density method based on the modified Peng-Robinson equation of state for confinement effect. The model is first utilized to analyze pore-scale adsorption data from a krypton (Kr) gas adsorption experiment on graphite. Then we implement the model to conduct sensitivity analysis of the effects of pore size on gas transport for Kr-graphite and methane-coal systems. The model is finally used to study Kr diffusion profiles through a coal matrix obtained through X-ray micro-CT imaging. The results show that the sorbed phase occupies most of the pore space in organic nanopores with less than 10 nm due to multilayer adsorption, and surface diffusion contributes significantly to the total mass flux. Therefore, neglecting the volume of sorbed phase and surface diffusion in organic nanoporous rocks may result in considerable errors in the prediction of hydrocarbon production. The comparison between BET-based and Langmuir-based models shows that Langmuir-based models can only match the adsorption isotherm at low pressure and yield lower effective surface diffusion coefficients. Therefore, implementing a Langmuir-based model may be erroneous for an organic-rich reservoir with strong adsorption capacity during the early depletion period when the reservoir pressure is high.
Novel Simulator for Design and Analysis of Matrix Acidizing Jobs with Fluoroboric Acid in Sandstone Reservoirs
Authors: Qamruzzaman Mohammed , Khan Mandeep , Roy Dhirendra Chandra , Raman Ravi 
Published: September 2021

Abstract
Matrix acidizing with fluoroboric acid (HBF4) has gained special attention as not only it provides deeper penetration of in – situ generated hydrofluoric acid, but also stabilizes formation fines by binding them to the pore surface. While numerous mathematical models exist in literature for design and evaluation of conventional mud acid treatments, fewer attempts have been made in developing a lab validated model that can do so for fluoroboric acid treatments.
This paper presents a novel mathematical model that has been developed taking into account the chemical kinetics and equilibrium aspects of important reactions and fluid flow inside the reservoir rock. The solution to the governing equations has been obtained through tools of computational fluid dynamics (CFD). The model has been validated rigorously through use of state-of-the-art core flooding and ion chromatography setups. The resulting simulator can be used to design an optimum fluoroboric acid treatment by analysing the effects of all the important factors including reservoir temperature, formation mineralogy and job execution details like initial acid concentration, pumping rate, job volume and shut-in time post treatment.
Simulation results with the developed model indicate that although penetration of fluoroboric acid is much larger compared to mud acid, its overall effect on skin factor is inferior for temperatures less than 90 °C. Stimulation in such wells should be preferred with mud acid which can be followed by fluoroboric acid for fines stabilization. For temperatures more than 120 °C, stimulation effects of fluoroboric acid become comparable to that of mud acid. Under these conditions, it can be used as an alternate fluid to mud acid to prevent issues of secondary and tertiary precipitation. It is found that major stimulation benefits with fluoroboric acid are realized during pumping and subsequent shutting of well, which is a common practice with fluoroboric acid, has relatively smaller effect on skin factor. Apart from design and evaluation of fluoroboric acid treatments, the simulator can also be used for analyzing mud acid and mud acid followed by fluoroboric acid treatments thus enabling the user to select and design the best suited treatment for a given well.
Mechanisms and Mitigation of 3D Coupled Vibrations in Drilling with PDC Bits
Authors: Chen Shilin , Propes Chris , Lanning Curtis , Dunbar Brad 
Published: September 2021

Abstract
In this paper we present a new type of vibration related to PDC bits in drilling and its mitigation: a vibration coupled in axial, lateral and torsional directions at a high common frequency (3D coupled vibration). The coupled frequency is as high as 400Hz. 3D coupled vibration is a new dysfunction in drilling operation. This type of vibration occurred more often than stick-slip vibration. Evidences reveal that the coupled frequency is an excitation frequency coming from the bottom hole pattern formed in bit/rock interaction. This excitation frequency and its higher order harmonics may excite axial resonance and/or torsional resonance of a BHA. The nature of 3D coupled vibration is more harmful than low frequency stick-slip vibration and high frequency torsional oscillation (HFTO). The correlation between the occurrence of 3D coupled vibration and bit design characteristics is studied. Being different from prior publications, we found the excitation frequency is dependent on bit design and the occurrence of 3D coupled vibration is correlated with bit design characteristics. New design guidlines have been proposed to reduce or to mitigate 3D coupled vibration.
An Innovative Low Cost Well Monitoring Solution: W.A.N.D
Authors: Boero Rollo Jean Grégoire , Ordonez Varela John Richard , Ben Ghzaiel Tayssir , Mouanga Cedric , Luxey Arnaud , Risler Frederic 
Published: September 2021

Abstract
Wireless Autonomous Nano-sensor Device (WAND) system is a disruptive cost-effective micro-system for well monitoring. It allows to realize pressure, temperature, inertial, and magnetic field measurements in harsh conditions; it also offers Bluetooth low-power communication and Wireless charging capabilities.
Analysis’ results of an industrial offshore pilot realized in Congo (a world first in O&G industry in such complex environment), and major improvements implemented after this pilot are reported in this paper. Accomplished advancements comprise hardware and software developments extending operation lifetime, and simplifying on-site utilization.
To date, there is not a commercial solution of this type in the market, the realization of this project is a real innovation allowing practical and low-cost monitoring during well intervention while minimizing the risks associated with standard Rigless intervention. Other applications regarding dry-tree wells on tension-leg platforms (TLP), drilling and completion operations, and pipeline monitoring are being investigated, too.
The Same Drift Monodiameter Completion System in Solving Drilling and Well Infrastructure Challenges
Authors: Godfrey Matthew , Baker Roy 
Published: September 2021

Abstract
The public domain contains many work efforts that document the advantages of expandable drilling and completions systems within the industry (Filippov 1999, Lohoefer 2000). The ability to place a solid steel liner or patch into a well and transform it by cold working to a larger diameter provides an opportunity to drill deeper while maintaining sufficient wellbore diameter. The use of expandable technology has led to the development of a formable and retractable-segmented cone. The cone supports an expandable system capable of passing through the drift of a base casing that can then result in an expansion providing the equivalent drift diameter. The technology allows the placement of additional liner points in a well that can extend liner lengths as well as isolate sections of open hole that were previously impossible to isolate due to wellbore geometry restriction. There are no limitations on the number of open hole patches installed in a given well which are helpful when wells experience multiple drilling hazards. Each patch can pass through a previously installed patch.
The idea of monodiameter expandable liners began in the early 2000s (Dupal 2002, Dean 2003). This paper presents the technical challenges, solutions, and testing of a novel monodiameter system that expands 11-3/4 in. 47 lb/ft pipe which can result in a post-expansion drift diameter of 12-1/4 in. Finite element analysis helped transform the concept from the theoretical system to field execution. The work efforts show the successful testing of the monobore system at surface, and the resulting field trials demonstrate the ability of the technology to fulfil the installation objectives. In addition, the success of the methodology has led to the development of additional monobore system sizes.
Gas Migration in Wellbores During Pressurized Mud Cap Drilling PMCD
Authors: Samdani Ganesh Arunkumar , Rao Sai Sashankh , Gupta Vishwas Paul 
Published: September 2021

Abstract
In PMCD operations, reservoir gas is expected to migrate uphole, and the uncertainty in gas migration rates under downhole conditions leads to challenges in planning logistics and fluid requirements. Estimates of migration velocities based on current methods (e.g. Taylor-bubble correlation) are highly conservative and involves simplifying assumptions. This paper presents a systematic approach to understanding the fundamentals of gas migration in wellbores, relates it to field data, and provides recommendations to improve PMCD design and planning. Our approach includes analysis of PMCD field data, multiphase flow literature and computational flow simulations. The field data on gas migration is used to establish the field-scale parametric effects and observed trends. Multiphase flow literature is used to qualitatively understand some of these parametric effects at downhole conditions. A comparison between multiphase flow literature and field data overwhelmingly demonstrates the gaps in understanding of underlying physics. 3-dimensional multiphase CFD simulations for a representative well geometry and downhole conditions are used to understand gas migration physics at downhole conditions and the reasons for its sensitivity to different conditions.
CFD simulations showed a strong impact of pressure on bubble breakup. As a result, the gas migrates as a slow-moving swarm of smaller bubbles. The formation of smaller bubbles from a given gas volume is a rate dependent process and requires a finite time to reach to an equilibrium/steady-state. The field conditions provide both high downhole pressure and sufficient length-scale for formation of smaller slow-moving bubbles. For the same reason, small scale-experiments are limited in their application for field-scale designs due to use of low pressure and/or insufficient length-scales. The CFD results also compare well with field data in showing ~30% holdup of migrating gas at low migration rates and negligible effect of rotation and wellbore geometry i.e. annulus vs openhole. The extent and rate of disintegration of gas volume (bubble) has a negative correlation with well inclination, liquid viscosity, and surface tension. The rheology and liquid viscosity also affect the ability of liquid to sweep the gas back into the reservoir and therefore it is expected to have an optimum range for a given PMCD application. Use of high viscosity fluids for typical downhole well conditions is counterproductive and results in higher gas migration rates and therefore not recommended. The understanding of downhole physics is expected to improve logistics/storage/ planning/fluid choice and lead to lower gas migration rates and reliable operation. The same approach can be applied to other operations and scenarios where gas migration velocities are a key design factor.
Pressure Interpretations in Acid Fracturing Treatments
Authors: Pandey Vibhas J. 
Published: September 2021

Abstract
Acid fracturing is a preferred method of stimulating low permeability limestone formations throughout the world. The treatment consists of pumping alternating cycles of viscous pad and acid to promote differential etching, thereby creating a conductive acid-etched fracture.
Acid-type, pad and acid volumes, and the injection rates in the designed pump schedule are based on treatment objectives, rock-types and in-situ conditions such as temperatures, in-situ stress, proximity to water-bearing layers, and others. During the acid fracturing treatment, the acid-rock interaction is often marked by signature pressure responses, that are a combined outcome of acid reaction kinetics, responses to changes in fluid viscosity and densities, fluid-frictional drop in narrow hydraulic fractures, and other such parameters. This paper focuses on interpretation of bottomhole pressures during acid fracturing treatment to separate these individual effects and determine the effectiveness of the treatment.
Unlike propped fracturing treatments where most fracturing treatments result in net pressure gain, acid fracturing treatments seldom result in net pressure increase at the end of the treatment because the in-situ stresses are generally relieved during the rock-dissolution and fracture width creation process that results from acid-mineral reactions. Not only is the extent of stress relief evident from the difference in the start and the end of the treatment instantaneous shut-in pressures, the loss of stresses is also apparent during the treatment itself, especially in jobs where the treatment data is constantly monitored and evaluated in real-time. The study reveals that the changes in pressure responses with the onset of acid in the formation can be successfully used to determine the effectiveness of treatment design and can aid in carrying out informed changes during the treatment. Better understanding of these responses can also lead to more effective treatment designs for future jobs.
The interpretation developed in the study can be applied to most of the acid fracturing treatments that are pumped worldwide.
Closing the Gap in Characterizing the Parent Child Effect for Unconventional Reservoirs - A Case of Study in Vaca Muerta Shale Formation
Authors: Lerza Alejandro , Cuervo Sergio , Malhotra Sahil 
Published: September 2021

Abstract
In Shale and Tight, the term "Parent-Child effect" refers to the impact the depleted area and corresponding stress changes originated by the production of a previously drilled well, the "parent", has over the generated hydraulic fracture geometry, conforming initial drainage area and consequent production performance of a new neighbor well, called "child". Such effect might be considered analogous to the no flow boundary created when the drainage areas of two wells meet at a certain distance from them in conventional reservoirs; but, unconventional developments exhibit higher exposure to a more impactful version of this phenomena, given their characteristic tighter well spacing and the effect pressure depletion of the nearby area by the neighbor well has over the child well's hydraulic fracture development.
Due to the importance the Parent-Child effect has for unconventional developments, this study aims first to generally characterize this effect and then quantify its expected specific project impact based on real field data from the Vaca Muerta formation.
To do so, we developed a methodology where fracture and reservoir simulation were applied for calibrating a base model using field observed data such as microseismic, tracers, daily production data and well head pressure measurements. The calibrated model was then coupled with a geomechanical reservoir simulator and used to predict pressure and stress tensor profiles across different depletion times. On these different resulting scenarios, child wells were hydraulically fractured with varying well spacing and completion designs. Finally, the Expected Ultimate Recovery (EUR) impact versus well spacing and the parent´s production time were built for different child´s completion design alternatives, analyzed and contrasted against previously field observed data.
Results obtained from the characterization work suggests the parent child effect is generated by a combination of initial drainage area changes and stress magnitude and direction changes, which are both dependent of the pressure depletion from the parent well. Furthermore, the results show how the well spacing and parent's production timing, as well as parent's and child's completion design, significantly affect the magnitude of the expected parent child effect impact over the child's EUR.
Condensate Recovery from Tight Gas-Condensate Reservoirs using a new Method Based on a Gas-Based Chemical
Authors: Nasieef Abdulelah , Jamiolahmady Mahmoud , Doryanidaryuni Hosein , Restrepo Alejandro , Ocampo Alonso , Chakrabarty Toushar , Seteyeobot Ifeanyi 
Published: September 2021

Abstract
Recovery from gas condensate reservoirs, when the pressure is below dew point pressure (Pdew), is adversely affected by the accumulation of condensate in the near wellbore region. The mitigation of the near-well bore condensate banking is the main purpose of any enhanced recovery method implemented in gas condensate reservoirs.
In this work, a new method was tested to improve condensate recovery by using a chemical that was delivered using hydrocarbon gas as a carrier into a very low permeability and very low porosity reservoir rock. Chemicals are typically injected using liquid carrier solvents. The use of hydrocarbon gas as the carrier provides a remedy to mitigate condensate banking in very low permeability cores by minimizing complications associated with low injectivity and back flow clean-up process requirements of an injected liquid.
The chemical potential was evaluated by recording production data from unsteady-state coreflood experiments. The injection of the chemical with equilibrated gas resulted in condensate saturation to decrease from 19.6% to 6.5%. This decrease was not instantaneous and took some time to occur indicating that the chemical needs time to interact with the resident fluid and rock. The benefit of the method, at the field scale, was also estimated by performing single-well numerical simulations that use relative permeability (kr) data which history matched the measured coreflood production data. The results of these preliminary simulations also showed improved recovery of gas and condensate compared to pure depletion, without chemical, by around 40% for the cases considered.
A Cost-Effective Stimulation Workflow Unlocks New Perspectives for Matrix Acidizing in Openhole Horizontal Tight Carbonate – A Case Study from West Kuwait
Authors: Al-Sabea Salem , Patra Milan , Abu-Eida Abdullah , Al-Azmi Nasser , AlEidi Mohammad , Al-Dousari Mohamad , Al-Qattan Hasan , Salem Abrar , Badrawy Kareem , Peiwu Liu , Enkababian Philippe , Molero Nestor , Pochetnyy Valentin , Baidas Abdullah 
Published: September 2021

Abstract
The Mishrif formation in west Kuwait is a tight carbonate reservoir having low oil mobility. It is fractured and heterogeneous with wide variation in porosity ranging from 10 to 25%, matrix permeability of about 0.1 to 10 md, and 20°API oil. Production tests and geomechanical study results have revealed that productivity is mostly from the high-permeability matrix and critically stressed fracture networks.
Recently, the Mishrif development has been dominated by horizontal wells to maximize reservoir contact and enhance productivity. However, a challenge in such openhole completion is the stimulation strategy requiring effective diversion technology due to the uneven acid distribution along the lateral section. To address those challenges, a novel engineered workflow has been implemented relying on distributed temperature sensing (DTS) to assess the fluid coverage across the openhole section. Results enable identifying high- and low-intake zones, segmenting the uncased section into intervals requiring different levels of stimulation, and making informed decisions regarding diversion requirements.
The intervention was conducted in two stages. Coiled tubing (CT) was the selected fluid conveyance method on the first stage given its capacity for more controlled fluid placement, and high-rate bullheading stimulation was selected for the second stage. During the treatment, multiple challenges were faced, mainly driven by a high-permeability streak identified by the DTS near the heel of the lateral. The CT stimulation procedures were modified on the spot, and measures were taken to minimize the impact on the thief zone, which included a combination of diversion techniques, such as high-pressure jetting, dual injection, and pumping of a near-wellbore nonreactive diverter, which is composed of a customized blend of multimodal particles and degradable fibers to minimize fluid leakoff into the high-intake zone. Likewise, real-time downhole telemetry was crucial throughout the CT stimulation because it allowed the highest injection rate possible below the preset pressure limits, continuous monitoring of downhole dynamics along the intervention, and optimal actuation of the high-pressure jetting tool. Upon completion of the CT stimulation, a second DTS log was carried out to evaluate the fluid coverage and effectiveness of the diversion strategy, enabling further adjustment of the bullhead stimulation program.
This stimulation workflow implemented in west Kuwait represents a cost-effective alternative to stimulate openhole tight carbonates. This study brings new perspectives for treating complex reservoirs in the region, and shares lessons learned for future interventions.