bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Revelation of Minor Reservoir Opportunity: Realizing Low Resistivity Contrast Reservoir Play Type in Baram Delta Basin East Malaysia, Thru REM Log Enhancement and Comprehensive Water Salinity Analysis
Authors: M Shah Jamari , Md Dahlan Nur Athirah , Kamarulzaman M Naquib , C A Razak M Amin , Jamaluddin Junirda 
Published: March 2019

Abstract
Low Resistivity low contrast (LRLC) reservoirs were normally disregarded due to high water saturation and classified as tight sand. LRLC reservoir defined as Pay that has low resistivity contrast between sand and adjacent shale due to presence of conductive mineral or fresh water. Hence, this paper will transform the standpoint by demonstrating values and potential reserve addition underneath LRLC reservoir which proves that it could contribute equally as the conventional reservoir and realizing potential reserve growth.
HY field located in Baram Delta Basin East Malaysia has been producing for more than 40 years and classified as lower coastal plain to coastal environment. The reservoir is loosely consolidated, fine to very fine sandstone and interbedded with shale. Z reservoir (Low Resistivity contrast reservoir) initially identified as gas-bearing reservoir with fresh water salinity of 2k-4kppm. Plus, difference in resistivity values between sand and adjacent shale only separated by ~3ohmm .Due to these claims, there is no Oil interpreted below the gas level and been neglected for years.
A robust water salinity investigation supported with the geological point of view and water sample taken at the wellhead, Project Team proposed the water salinity should be 10k-15k ppm which is more saline than previously assumed. Revision in water salinity value has led to pinpoint Z reservoir as Oil bearing reservoir and recover estimated ~200 ft Pay of Oil column in Z reservoir.
An appraisal well was drilled for data gathering and exploring potential in the deeper sections, hence serve as a platform for further petrophysical evaluation in the Z reservoir. As a result, Project team managed to take Oil sample and Oil gradient for Z reservoir. In addition, PVT lab result showed the oil sample taken having similar fluid property as the produced oil in the major reservoir. Based from the existing static model, potential additional of recoverable reserves was calculated around 20 MMstb for the Z reservoir. This has been an eye opener for the team to give an extra attention and emphasis on the true potential beneath the LRLC reservoir.
Role of Geomechanics and Integrated Reservoir Characterization in Production Enhancement from a Heterogeneous Carbonate Reservoir: A Success Story from Kuwait
Authors: Padhy Girija Shankar , Al-Rashidi Tahani , Gezeeri Taher Mohd , Shinde Ashok , Perumalla Satya , Zhou Chong 
Published: March 2019

Abstract
The subject upper Cretaceous carbonate formation has been characterized as a heterogeneous reservoir with varying facies and petrophysical properties. Distribution of facies strongly varied not only with depth, but also laterally across the field. Upper part of the reservoir is dominated by natural fractures whereas lower part is predominantly argillaceous with mud enrichment. In addition, presence of laminations and vugs enhanced the heterogeneity of the reservoir. Very few wells were drilled and some of them were fractured. This paper demonstrates how geomechanical and integrated reservoir characterization has shown value in well placement strategy.
Built number of well-based geomechanical models with data from all wells in order to capture reservoir heterogeneity in models. These models quantified the distribution of rock mechanical properties and pore-pressure as well as present day principle stresses. In addition, these models were integrated with geological model as well as seismic data to generate a 3D geomechanical model. After a thorough rock typing and petrophysical classification, some patterns were recognized in terms of presence of natural fractures in certain layers. However, the production contribution of these natural fractures was unclear. Upon combining all available sensitive fracture indicators, a DFN model was built and calibrated. Finally, the 3D geomechanical model combined present day in-situ stress and pore pressure magnitudes, mechanical properties of all rock facies and natural fracture occurrences at field scale. A thorough well production analysis was also performed to validate the role of natural fractures during production.
After systematic integration of diverse sub-surface data sets in 3D geomechanical model, some natural fracture subsets were identified that are optimally oriented to become critically stressed at present day stress regime. Upon further analysis, a new parameter "Index of Critically Stressed Fractures (iCSF)" was created that captured the spatial distribution of networked fracture sets in 3D model that are geomechanically favorable for fluid flow. Number of geomechanical sweetspots were identified at field scale and correlated these areas with other data. It was also recommended to stimulate wells with certain practices.
Integration of geomechanical models with production analysis and natural fracture indicators delivered value in identifying geomechanical sweetspots that have potential to flow. Distribution of these sweet spots provided a strategy for well placement as well as stimulation. In addition, this paper also exhibits logical integration of findings from geosciences and engineering disciplines to make informed decisions on well planning in order to maximize the production from challenging reservoirs.
Process Integration and Optimization of CO2 Removal from Natural Gas Using Cryogenic Distillation System
Authors: Surmi Amiza 
Published: March 2019

Abstract
The development of CO2 separation technologies will enable the monetization of undeveloped gas fields with a high level of CO2, thus providing commercial enterprises a superior competitive edge for future international field acquisitions. The cryogenic distillation system has been identified as one of bulk CO2 separation technologies for high CO2 removal from natural gas. It is a more favourable CO2 separation technology than chemical or physical absorption due to its independence from absorbents, which require a greater footprint, weight and energy. It is targeted for bulk CO2 removal from the natural gas stream 80% down to 20%, and it must be efficient and cost-effective to ensure that the overall economics of a development are positive.
In-house process simulation software was used to model a cryogenic distillation column system, while an experimentally validated thermodynamic model was used to verify the phase behaviour of the components, potential CO2 solidification and hydrate formation at the operating pressure and temperature conditions. This modelling encompassed critical operating conditions such as high operating pressure and low operating temperature. This is crucial especially at lower temperature and blowdown condition to prevent piping and equipment blockage which might lead to catastrophic equipment failure.
A pilot scale cryogenic distillation unit was studied in this paper with pre-mixed feed consists of CO2 and natural gas to investigate separation performance as well as to examine the operational aspects of the technology. Efforts should be made to reduce energy consumption for such applications. In this paper, pinch analysis tool is utilized to analyse and optimized the Heat Exchanger Network (HEN) of the Cryogenic Distillation System for bulk CO2 separation. Column operating pressure, condenser and reboiler temperatures and feed conditions were varied to examine the effect on energy consumptions and for comparison with process simulation results. It was found that condenser duty decreased by 50% while reboiler duty increased by 100% when operating pressure was increased from 35 bar to 50 bar to achieve the same product specification. Substantial energy reduction for external cooling was attained through pinch technology by taking advantage of the Joule-Thomson effect when expanding high pressure liquid CO2 stream to a lower pressure. Optimal operating conditions, the effect of impurities and alternative refrigeration systems are identified as current gaps in this study.
Operational issues were identified and mitigated in this study, which will further the understanding and scaling-up of commercial plants, particularly blowdown study and CO2 solid and hydrate formations and potential mitigations.
Autonomous Reservoir Nano-Agents
Authors: Mashat Afnan , Shi Nan , Squires Todd , Abdel-Fattah Amr 
Published: March 2019

Abstract
This article demonstrates the ability of salinity gradients that naturally exist, or could otherwise be induced, in the reservoir to target-migrate nanoparticles in porous and fractured reservoirs. This nanoparticles’ autonomous migration marks a significant milestone towards the development of reservoir nano-agents that self-migrate in deep and hard-to-reach regions in the reservoir without the aid of advective flows.
Direct microscopic visualization experiments were conducted in representative micromodel environments to quantify the displacement and velocity vectors of model nanoparticles in response to different concentration gradients of solutes in the absence of advective flow. One set of experiments used solutes with different divalent ions and another set used high-salinity water to create the concentration gradients.
Nanoparticle migration distance and speed up or down the imposed gradients were precisely obtained from high resolution image sequences using particle image velocimetry (PIV) algorithms. The rate at which the particles migrate was calculated and used to validate and extend existing theories to high salinity conditions.
Results showed that, in the absence of flow, nanoparticles readily migrate upon exposure to a given gradient, either up or down the gradient, depending on the solute composition (diffusiophoresis). The rate at which the particles migrate is on the order of μm/s and was found to be dependent on: 1) the gradient magnitude, 2) absolute value of the minimum and maximum concentration of the gradient, 3) ion diffusivities.
The results presented here provide new insights into the transport mechanisms of nano and micro particles in oil reservoirs where naturally-occurring or induced solute and chemical gradients exist. These results provide a platform for the development of reservoir nano-agents that self-migrate in deep and hard-to-reach regions in the reservoir without the aid of advective flows.
Hydraulic Fracturing in a Devonian Age Carbonate Reservoir: A Case Study
Authors: Istayev Almas , Jatykov Temirlan , Kosset Talgat 
Published: March 2019

Abstract
Recent technological progress within the petroleum industry has enabled much deeper discoveries than conventionally accepted depths. One example of such exploration success is drilling and stimulating an appraisal well in a Devonian age carbonate reservoir in northwestern Kazakhstan.
This paper describes a successful case study of hydraulic fracturing stimulation as a solution to enhance hydrocarbon recovery. A specific workflow developed for stimulation of high pressure and temperature low permeability reservoir is suggested. This workflow includes an adapted study of petrophysical properties, fracture geometry modeling, and completion design selection. Fracture stimulations and pre- and post-completion results are also analyzed and compared.
One of the main tasks of the technical staff was designing a production enhancement method which would maintain positive return on investment (ROI) for the project. A reservoir study was conducted during the planning stage of this pilot project. The design workflow included geomechanical analysis to estimate reservoir rock properties. Fracture stimulation modeling was performed to forecast treating pressures and adjust treatment stage sizes to help achieve optimum fracture geometries. Perforation intervals were selected and recommended to provide the best placement of fracturing fluid and proppant into the zone of interest.
Previously, the operator had attempted an acid wash, which was unsuccessful because of coiled tubing (CT) capability limitations, making it impossible to inject acid in desired rates into the rock due to low permeabilities and high stresses. Then, based on the final designed stimulation treatment plan, the operator conducted a massive proppant and acid fracturing stimulation operation, where high pressure pumping was performed at the treating pressures above formation breakdown limits. Created hydraulic fractures provided conductive pathways for reservoir fluid inflow. This method has shown an improved recovery of reservoir fluid. This hydraulic fracturing technique provided economically effective field exploration in the previously undeveloped part of the licensed block.
Field execution has shown challenges with respect to performing operations in deviated wells. Observations conducted in three stages during the pilot project are described and conclusions presented. This paper also describes operational difficulties with equipment combined with materials logistics.
FracBots: Overview and Energy Consumption Analysis
Authors: Alshehri Abdallah , Martins Carlos 
Published: March 2019

Abstract
Fracture Robots (FracBots) prototype has been successfully designed, developed, fabricated and tested in the laboratory. They are magnetic induction (MI)-based wireless sensor nodes that have the inter-node wireless communication, sensing and localization estimation capabilities. FracBots are miniature devices that can operate as wireless underground sensor networks (WUSNs) inside hydraulic fractures to collect and communicate important data and generate real-time mapping. The energy source of the FracBots is a major challenge since the operational environment is the hydraulic fractures which impose a restriction on the size that doesn't allow enough space for the battery. In addition, the capability to extract the energy from a designate source is another key-role feature that has to be a function of the FracBots. In this regard, energy consumption analysis and evaluation has been done to ensure that all the FracBots have the required energy to work properly during the operation inside the hydraulic fractures. The electronic design of the FracBots must be highly efficient and capable of dramatically reducing power consumption. Thus, FracBots design is composed of ultra-low power electronic chips that enable a switch among an active mode, a deep sleep mode and a shutdown mode with automatic wake-up features (Low Power Modes (LPMs). Also, it includes an energy management unit that harvests surplus power stemming from the base station. This feature reduces the power consumption and ensure continuous operation. Based on our energy model and electronic design, deep analysis of the harvested and consumed energy is conducted in a laboratory testbed. Results of this study show the capability of the FracBots to harvest the required energy to operate and perform all the communications and sensing functionalities. Using ultra-low power electronic chips based on ferromagnetic technology (FRAM) and energy management unit reduce the power consumption of the FracBots by 50% at least.
Surface Seismic with DAS Changes Land Acquisition
Authors: Bakulin Andrey , Silvestrov Ilya , Pevzner Roman 
Published: March 2019

Abstract
Distributed Acoustic Sensing (DAS), as a seismic sensor, has unique features allowing us to record multiple datasets with variable acquisition parameters set inside the recording box, while using one continuous recording cable and a single round of shooting. We reveal how these distinct features allow DAS to deliver multi-scale data and have the capability to focus on both the near surface and deeper targets simultaneously. We present synthetic and field examples of "deep" and "shallow" DAS surveys and demonstrate their effectiveness. The new capabilities of surface seismic with DAS technology comprise a sensing revolution that addresses long-standing near-surface issues in land seismic without compromising the deeper imaging. Achieving similar capabilities with point sensors could be done but would lead to ballooning acquisition costs, whereas surface seismic with DAS can deliver them at a cost less than conventional geophone acquisition available today.
Implementing a Drilling Reporting Data Mining Tool Using Natural Language Processing Sentiment Analysis Techniques
Authors: Kowalchuk Peter 
Published: March 2019

Abstract
Drilling operations generate much information, such as daily drilling reports and reports generated by service companies, support personnel, and other stakeholders. These reports can be unstructured with information presented in a variety of formats. The extraction of this information is frequently challenging, which limits its use in future projects. Natural language processing provides an efficient way of mining and obtaining knowledge. This paper demonstrates how these techniques were used to analyze vast amounts of historical documents to quickly rank well complexity and determine which aspects of drilling operations were most critical.
Sentiment analysis can be used to classify documents and other pieces of information into separate categories. In social media, it is used to analyze the collective perception of a given trending item. The technique was used here to classify wells into two ranked categorized lists. First, a classification listed wells by drilling issues. Second, a complexity ranking was defined so that each well could be classified as easy or difficult to drill. To build the sentiment analysis tool, a random set of training wells and their respective documents were selected. From these documents, a list of words was identified in what became known as highlighting sessions. During these sessions, subject matter experts (SMEs) classified words found in the documents. This "bag of words" was then used to train a classifier capable of ranking the wells related to the documents. A probability was associated to each well, providing a likelihood of inclusion in a given category.
The methodology proved to be successful, ranking drilling documents in both defined category sets. Results show that the list of ranked wells can be used by SMEs to identify which wells are relevant and deserve detailed analysis. The list generated for both categories provided a guideline for further analysis, particularly identifying wells with little value. Results also showed the importance of correctly developing a list of words, an adequate training set, and the language used, as well as the need for SMEs to produce the final analysis. The technology showed promising results with real-world applications being conceivable with its current level of maturity. However, the results also indicated room for improving its effectiveness by refining the highlighting sessions, word lists, types of classifier used, and final ranking methodology.
The use of methods and technology to help improve and enable the analysis of unstructured data in the drilling space should increase over time. This paper shows how current technology can already be used in practical real-life cases to produce tangible value.
Study on the Impact of Core Wettability and Oil Saturation on the Rheological Behavior of CO2-Foams
Authors: Beunat Virginie , Pannacci Nicolas , Batot Guillaume , Gland Nicolas , Chevallier Eloïse , Cuenca Amandine 
Published: March 2019

Abstract
Foam processes aim to improve the efficiency of gas-based injection methods through gases mobility control. They have been successfully applied in various EOR contexts: CCUS through CO2-EOR, steam injection for heavy oil reservoirs, and also in fractured reservoirs. The success of such processes depends on multiple factors, among which the interactions between the surfactants, the oil and the rock, play a key role. The purpose of this study is to provide initial answers by focusing on the influence of wettability and oil saturation on the behavior of CO2-foam flows.
A new coreflooding set-up is designed for ‘mesoscopic’ cores (2.5 cm diameter) in order to conduct foam formulation screening and perform faster foam injection tests at reservoir conditions (up to 200 bar and 60 °C). This set-up was first validated by repeating experiments performed previously on classical corefloods with 4 cm diameter cores. Similar results in terms of mobility reduction were obtained for the same operating conditions with a considerable reduction of test duration.
All experiments were performed with Clashach sandstones cores having approximatively 16 % porosity and 600 mD permeability. Two gas compositions have been studied: (1) a dense supercritical CO2 (density of 638 kg/m3 at P = 160 bar, T = 60°C) and (2) a non-dense gas mixture of CO2 and CH4. For each gas composition, four foam injection tests were carried out: two on water-wet rock samples, two others on crude-aged core samples, and for both in the absence and in presence of oil. Anionic surfactant formulations and gas were co-injected with a gas fraction of 0.7. Foam rheology was assessed by measuring foam apparent viscosity through a scan of interstitial velocities.
All the tests performed in dense conditions have highlighted the generation of strong foams, which present shear-thinning rheological behavior; the apparent viscosity decreases as a power law of the interstitial velocity. An influence of the wettability is observed on the foam apparent viscosity, which drops off by 30 % in altered wettability rock samples. When samples were originally saturated with oil at Swi, the level of apparent viscosity remains globally unchanged but the kinetics of the initial formation of the foam is slower with oil than without.
Foam flooding experiments are sometimes carried out simply in the presence of oil without taking into account the influence of wettability, which appears to be as important, if not more, than the oil saturation itself. These results will hopely provide some guidance for future foam studies and raise awareness on the importance of these parameters.