bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gas Lift Optimization Study in Brownfields: A Review on Dual String Gas Lift Injection Allocation In Malaysian Offshore Fields
Authors: Suggust Alister Albert , Kueh Jing Zhi 
Published: September 2022

Abstract
Sarawak offshore wells are mostly completed with dual string completion and are heavily relying on gas lift as the primary artificial lift. Dual string gas lift is an economical way to selectively produce from multi-stacked reservoirs in Sarawak fields. However, it poses great challenges in terms of operations, troubleshooting, allocation and optimization as both strings share a common annulus. Dual string gas lift performance diagnosis need to be done from time to time to ensure the strings production are optimized at well level.
Gas injection rate is a critical input in predicting the well performance based on the gas lift performance curve. However, the gas lift injection rate for dual string is measured at well – not at string level. The gas lift injection rate into each string needs to be allocated correctly either through well modelling calibration approach, testing one string while shutting its neighbor or well tracer application. After allocating the gas lift injection rate into each string correctly, well modelling prediction run at done to mitigate multipointing issues, design optimum point of injection, establish optimum injection rate at well level and determine the optimum casing head pressure.
The operator has proposed for a workflow to correct the dual gas lift injection allocation based on well modelling calibration. The workflow was implemented and resulted in multiple optimizations in terms of gas lift valve change program, choke optimization and gas lift rate optimization. Apart from that, the paper will also share on the findings from the well tracer application in correcting the gas injection allocation.
This paper will focus on the production performance check on dual string gas lift performance at well level. The findings from the study are subsequently monetized as quick-gain opportunities while the operator is embarking into long term study on assessing the alternative artificial lift strategy suitable for a brownfield. The lessons learned will also be applicable to oil fields with similar situations to further improve the fields’ production.
Microfluidic Study of Polymer Permeability Reduction Mechanisms
Authors: Kenzhekhanov Shaken , Yin Xiaolong , Gussenov Iskander 
Published: September 2022

Abstract
Polymer solutions see broad applications in hydraulic fracturing, enhanced oil recovery, conformance control, and groundwater remediation. However, due to the high viscosity of polymer solutions, flows after polymer injection are often subjected to significant pressure build-up, the mechanism of which is not well studied, especially on the effect of distribution of fluids in the pores.
In this study, we used microfluidics micromodels to visualize the distribution of fluids in porous media. NOA81 micromodels with close-to-real-rock pore dimensions were fabricated and used for simulating flooding experiments. Relative permeability was measured at steady-state flow rates and injection pressures. Then, fluid distribution was analyzed using microscopy image analysis.
We observed that the distribution of fluids in a porous medium has a direct impact on the pressure drop. The relative permeability of water and oil after polymer flow was disproportionally low, which is consistent with core flooding experiments. The increase in the pressure drop due to polymer trapping can be correlated to occupancy, orientation and alignment of pore channels. A mathematical model was developed to describe the correlation between pore-scale fluid distributions and the end-point relative permeability; it can be used for understanding and enhancing oil/water flows during/after polymer injections.
Failure Pressure Prediction of Defective Pipeline Using Finite Element Method and Machine Learning Models
Authors: Liu Wei , Chen Zhangxin , Hu Yuan 
Published: September 2022

Abstract
Oil and gas pipeline failure and leakage can seriously damage people's lives and the ecosystem. The prediction of failure pressure for pipelines with damage is one of the most important and challenging tasks faced by industry, which affects the assessment of pipeline safety. Previous studies widely used industrial models or the finite element (FE) method to predict the failure pressure. However, the industrial models may give limited information, and the FE method has much heavy computation burden.
In this work, three machine learning models - artificial neural network (ANN), XGBoost (XGB) and CatBoost (CAT) are developed for forecasting the failure pressure of pipelines with defects. Firstly, the simulation results of the FE method are validated by real failure pressure and compared with the calculation results of industrial models (ASME-B31G and DNV). Then 180 pipeline samples including pipeline attributes and defect sizes collected from real in-line inspection data in a pipeline company and the corresponding FE simulation results of failure pressure of these 180 defective pipelines are used for the training and testing of the machine learning models.
The results show that the simulation accuracy of the FE method is higher than the calculation accuracy of the industrial models, and the FE simulation results are suitable to be the outputs of machine learning models. The three machine learning methods all provide satisfactory prediction accuracy in failure pressure. Specifically, CAT is the best machine learning method in this study for its lowest relative error (3.11% on average), mean absolute error (0.53), root mean square error (0.78) and highest coefficient of determination (R2) up to 98% in testing. Moreover, the machine learning models present better performance on average relative errors compared to the industrial models. CAT shows higher accuracy than the industrial models and FE simulation on minimum and average relative errors. Finally, the prediction result of CAT is used to discuss the effect of input features on failure pressure of pipelines, which demonstrates that the importance of features follows the order of pipeline thickness &gt; pipeline outside diameter &gt; defect depth &gt; defect length &gt; defect width.
Once the above machine learning methods are used in industry, more and more real data will be collected to train a model and make it more accurate. In this way, these methods will provide an efficient way to evaluate the safety of defective pipelines. In addition, the failure pressure of pipeline could be estimated to help operators figure out a pipeline condition and further prioritize the pipelines for maintenance.
Effect of Formation Compaction and Subsidence on Sliding Sleeve Performance
Authors: Getzlaf Nick , Whyte Rio , Vanee Mike , Mberia Stanley , Gillis Brock , Werries Michael 
Published: September 2022

Abstract
Formation compaction and subsidence forces due to reservoir drawdown have the potential to inhibit the function of sliding sleeves and similar completion systems. The sliding sleeves discussed have the ability to be opened and closed multiple times, allowing for flexible stimulation and production operations. Field data suggested a link between high sliding sleeve function forces and preceding zonal production. The objective was to minimize these effects to give the operator full functionality of the sliding sleeves over the life of the well. This paper will outline how this was achieved, and the results of comparative lab testing.
The overall approach was to (1) understand the magnitude and effects of the formation forces, (2) implement product improvements, and (3) validate results through lab testing the proposed solutions.
A case study was conducted for 4.5 in. 21.5 lb/ft & 5.5 in. 32.6-35.3 lb/ft casing and sliding sleeves installed in the Valhall field. Wells drilled in the Valhall field had previously suffered production casing collapse failures due to formation compaction and subsidence (Pattillo and Kristiansen 2002). Switching to the current heavy weight casing resolved the issue. The heavy weight casing collapse pressure ratings were used in the early analysis to determine maximum uniform collapse resistance and radial deformation of the sliding sleeve components. Thick-walled cylinder calculations were insufficient for predicting the effect of the non-uniform loading exhibited downhole, as well as predicting metal-to-metal contact within the sliding sleeves due to abrupt changes in geometry. FEA modelling was completed for predicting metal-to-metal contact due to a non-uniform load.
Sleeves with improved mechanical collapse resistance were designed and built. Lab testing was conducted by applying a mechanical radial force simulating the formation load to (1) the original sleeves, (2) the newly improved sleeves, and (3) host casing samples. Sliding sleeve performance was assessed through the resultant opening and closing forces. Test results verified the model for radial deformation due to formation forces, and the effect on sliding sleeve performance. The improved sleeves showed no change in performance with a range of applied radial load, whereas the original sleeves showed significant increases in function force.
Completion design improvements can enable novel methods of well stimulation and production in areas prone to formation compaction and subsidence forces. These forces can have major effects on the completion and production of a well but are rarely quantified and accounted for in sliding sleeves or similar completion systems designs. At the time of writing, the improved sliding sleeves have been successfully run in a field trial, though did not produce prior to functioning.
Stranger Things 4: Placement Simulators Accuracy For ECD and Pressure Predictions
Authors: Shine Joe , Heinold Thomas , Lawrence Don 
Published: September 2022

Abstract
Cement placement simulators are valuable tools predicting anticipated pressures and equivalent circulating densities (ECD) for a given application. The simulators guide users in maintaining wellbore stability for a range of operating conditions unique to the application while helping to achieve the isolation requirements. There are various functions in the simulators, based upon the inputs, which contribute to the pressure and ECD predictions. Most of the available literature shows consistency for the solving the various transport equations of fluid dynamics including pressure losses as a function of flow regime, wellbore geometry, and fluid rheological model. Therefore, a comparison study should demonstrate consistency to avoid uncertainties in a given simulators prediction accuracy. The manuscript investigates the prediction differences in four available simulators that depending on the type of variability observed, could affect a well's integrity.
Relative Permeability Determination of Supercritical CO2 and Equilibrated Carbonated Water in Carbonated Rock of Brazilian Pre Salt Using Experimental and Simulation Methods
Authors: Vidal Vargas Janeth Alina , Borges Carvalho Talisson , Caicedo Garzon Alexander , Valladares de Almeida Rafael , Koroishi Erika Tomie 
Published: September 2022

Abstract
The relative permeability curve is the key parameter to determine the CO2 injection strategy in EOR and CCS processes as it can predict the CO2 flow over the reservoir life, and also through hysteresis it is possible to quantify the changes in the reservoir due to CO2 injection. In order to improve simulation fit and increase reliability in storage assurance the research work concerned experimental, analytical and simulation methods to study two-phase relative permeability of scCO2/equilibrate carbonated brine (ECB) system at reservoir conditions (5,000 psi and 70°C). Two techniques were used in order to perform the laboratory experimental tests for unsteady state using reservoir rock composite: X-ray computed tomography and mass balance. The absolute permeability was 106.7 (md) and the composite porosity measured by CT was 18.6%. At the end of drainage, the irreducible saturation (Swi) of ECB results by CT and mass balance were 39.5% and 36.2%, respectevely. The CO2 trapped was 11.09% from the CT data at the end of imbibition test. A simulation model was created using GEM/CMG and eight parameters of the model were optimized using the CMG Bayesian Engine method (CMOST/CMG simulator). The model fitting results are consistent with the experimental results (pressure differential, water production curve and saturation profiles). The history matching results for relative permeability curve provided Corey's exponents values for drainage test: Ng=4.76, Nw=2.30 and critical saturation of gas and water respectively, Sgcrit=0.1268 and Swcrit=0.3696. According to the results obtained from the simulation model, variation in permeability and porosity was observed due to dissolution and precipitation. The average values obtained for these parameters were 119.6 mD and 14.3%, respectively. The experimental work carried out to develop the relative permeability of scCO2/ECB under reservoir conditions and using sample of reservoir rock provided higher reliability due to the both measurements techniques appointed similar results. Also, the analytical approach performed in CMG GEM from experimental data promotes accuracy and confidence. Both experimental and analytical approaches provide reliable results to fill gaps in the literature and practice of science such as the determination relative permeability curve of water-CO2 using equilibrated carbonated brine and the system modeling using GEM/CMG.
Casing Failures in High Temperature Geothermal Wells: An Analytical Study
Authors: Kang Yongfeng , Samuel Robello , Kumar Vagish 
Published: September 2022

Abstract
In geothermal wells, temperature effect plays a very important role because of its high and cyclic temperature operation, usually in the range of 150 °C to 450 °C. Casing designed for traditional oil and gas production cannot be simply used in geothermal wells because of their different working conditions in these two scenarios. Thus, a robust design methodology for the geothermal casing is important from both economic as well as safety perspective.
Various studies have reported that the single most common failure in high-temperature geothermal wells is the mechanical overload of casing string due to constrained thermal expansion. In this research work, the classical Holliday approach for the post-yield design is reviewed and modified to include the effects of thermal yield strength deration effect and Bauschinger effect in the design process of high temperature cyclic loading encountered in case of geothermal wells scenarios.
In this study, the influence of thermal deration of yield and the Bauschinger effect on the allowable stress window is investigated. Empirical relations are used to estimate the reduction in the allowable stress window. In this research work, it has been found that the thermal derations effect and Bauschinger effect cause significant reduction in the allowable stress range. A reduction of 30% in the allowable stress window is observed due to these two factors from a case study. So, these two effects should be properly considered when doing a casing design for geothermal well.
Holliday approach ignored several effects due to the high temperature cyclic loading occurring in case of geothermal wells. This research work has addressed the limitations of the Holliday's classical approach to include these effects to make the design more robust for the geothermal well tubular design.
A Case Study on the Benefits of Implementing an Introductory Short Course on Oil and Gas to High-School Students
Authors: Alyafei Nayef , Retnanto Albertus , Cieslinski G. Benjamin 
Published: September 2022

Abstract
This paper highlights the benefits of a five-day short course on the basics of petroleum engineering for high-school students. Moreover, the course aims to introduce the oil and gas sector to students and stimulate their interest in considering petroleum engineering as a major in their future studies. The five-day short course was designed for two contact hours per day (a total of ten hours). The format adopted was approximately one hour covering the technical content, followed by one hour of experimentations. The course was conducted virtually, where the instructor conducted all the experiments. The students were encouraged to participate and take notes to make the session more dynamic. This paper will discuss the exact content covered every day in both lectures and experiments for people to follow. The equipment used in all experiments was very simple and easily procured. Twenty of the student participants filled out a survey at the end of the program. The outcome highly indicates that the students demonstrated a good understanding of the oil and gas sector as well as the objectives of considering petroleum engineering as a major. This program attempts to build bridges between the STEM education pipeline and the new demand for talent in the oil and gas sector. The novelty of this work is the high impact we observed on students’ motivation and potential enrollment to study petroleum engineering. Overall, the program is short and offers simple yet engaging content. Any school can easily adapt this program, and in this paper, we provide detailed guidelines to do so.
Increase in the Oil Recovery Factor through the Injection of Nano-Chemicals Dispersed in Gas
Authors: Gallego Arias Jhon Fredy 
Published: September 2022

Abstract
Tight reservoirs have different challenges, among them, there are several related to the low permeability of the rock and diverse damage mechanisms. Conventional Chemical Injection in these types of reservoirs has some disadvantages such as shallow penetration and the use of high volumes of chemicals. Therefore, new technologies such as chemical dispersion on a gas flow have been developed to achieve deeper penetration of the chemicals and mitigate formation damage in gas- condensate tight reservoirs by mobilizing condensate banks. However, the inclusion of nanoparticles in the dispersed phase for EOR processes is a novelty. Since silica nanoparticles reduce interfacial tension and alter the wettability of the rock, the objective of this study is to evaluate the effect of adding silica nanoparticles (S1) dispersed in two treatments (A and B) at a dosage of (10-100 mg·L−1) on wettability, interfacial tension, emulsion stability, and rock treatment adsorption. To compare them with a silica-based nanofluid, treatment C was also evaluated. The dosage selection of silica nanoparticles was made through static tests such as interfacial tension, contact angle, and static formation of emulsions. The best nanofluid among the ones prepared from treatments A and B was evaluated in dynamic tests to be compared with treatment C through the capillary blockage, oil recovery, and oil recovery in the perdurability scenario tests. Treatments A and C experienced a great affinity for the rock in the adsorption isotherms, while treatment B had less affinity for the rock. The addition of nanoparticles (S1) to treatments A and B at a concentration of 50 and 10 mg·L−1 respectively, led to an interfacial tension reduction of 16% and 40%, each one; and a respective water contact angle reduction of 17% and 2%. Furthermore, the addition of nanoparticles S1 promoted less stable emulsions, which is favorable for these processes. Finally, 26% of the additional increase in oil recovery and a greater perdurability was obtained with treatment B + 10 ppm Nps S1 in core displacement tests.
Detection of Emerging Ibrutinib Resistance by Flow Cytometry in Patients with Chronic Lymphocytic Leukaemia
Authors: Takács Ferenc , Kotmayer Lili , Czeti Ágnes , Szalóki Gábor , László Tamás , Mikala Gábor , Márk Ágnes , Masszi András , Farkas Péter , Plander Márk , Weisinger Júlia , Demeter Judit , Fekete Sándor , Szerafin László , Deák Beáta Margit , Szaleczky Erika , Borbényi Zita , Sulák Adrienn , Barna Gábor 
Published: September 2022

Abstract
Background: Although ibrutinib is effective drug in the treatment of chronic lymphocytic leukaemia (CLL), during the treatment acquired resistance may occur, making its detection an important issue. We aimed to find phenotypic markers on CLL cells which expression may correlate with the appearance of ibrutinib resistance.
Methods: We examined 28 (treatment naïve, ibrutinib sensitive, clinically ibrutinib resistant) peripheral blood (PB) samples. The surface markers` expression (CD69, CD184, CD86, CD185, CD27) were assessed by flow cytometry. Furthermore, the BTKC481S resistance mutation was tested using digital droplet PCR. We also investigated the change of the phenotype of CLL cells during ibrutinib treatment in one patient with acquired ibrutinib resistance.
Results: The expression of CD27 (p=0.016), CD69 (p=0.015) and CD86 (p=0.015) was higher in the clinically resistant cohort than in the ibrutinib sensitive cohort. Besides, we found that high CD86 and CD27 expressions accompanied by BTKC481S mutation. Our prospective study showed that the increase of the expression of CD27, CD69, and CD86 was ahead of clinical resistance with three months.
Conclusion: Our study suggests that the flow cytometric measurements of certain markers may reveal and predict the development of ibrutinib resistance, and this method may in the future become a part of the follow-up on patients treated with ibrutinib.
Flood as a fine scale driver of both floristic and functional differentiation in a ripariansystem
Authors: Miranda¹ Kaline Fernandes , Coelho² Polyanne Aparecida , Araújo¹ Felipe Carvalho , Morelli² Mariana Caroline Moreira , Pereira¹ Diego Gualberto Sales , de Paula Gabriela Gabriela Gomes Pires , de Souza Cléber Rodrigo , Santos Rubens Manoel dos 
Published: September 2022

Abstract
Flood forests are vegetation subject to seasonal floods. Situated in flood plains, they are systems under continuous changes due to the pulses of flooding, following the watercourse. Although these are singular ecosystems, there are little publications that report the floristic structure in floodplains, especially in Southeastern Brazil. This study aimed to characterize the composition, structure and diversity of the arboreal community in a flooding gradient, comparing them with the non-flood adjacent formations, at the mouth of Paracatu River, a tributary of São Francisco River, Minas Gerais, Brazil. For the structural survey of the arboreal community, we used the plot method, installed on both sides of Paracatu River. The individuals were identified at the species level. We sampled 1,276 individuals belonging to 85 species and 32 families. The Shannon Index (H`) regarding to the total sampling was of 3.40 nat.ind, with Pielou evenness index (J`) of 0.76. In terms of species importance, the six most important species comprised 46% of the total index of importance value. By means of similarity analysis, it was possible to verify the grouping of species along the ecounits, demonstrating the substitution of species along habitats, resulted of the temporal difference of the flooding in the environments. In conclusion, the flooding regimes, frequency and intensity determine the ecology of the river plains.