bluuebunny/crossref_metadata_2025_split huggingface dataset:
Depogrid: Next Generation Unstructured Grids for Accurate Reservoir Modeling and Simulation
Authors: Santoshini Samita , Harris Simon , Kashem Sheleem , Levannier Arnaud , Benabbou Azeddine , Viard Thomas , Macé Laetitia 
Published: October 2018

Abstract
As the oil and gas industry is moving toward tapping reserves in more complex structural environments, there comes the challenge for the reservoir modeling platform to accurately and robustly build and simulate a model to aid in making more trustworthy reserve estimates and field development plans. The 3D geocellular model sits at the core of an integrated seismic-to-simulation workflow, within which one can characterize and predict the behavior of reservoirs and can make confident quantitative decisions about one's assets. In structurally complex areas, the construction of accurate 3D models is often impeded by fundamental limitations of standard geocellular modeling technologies. With these limitations in mind, a new cut-cell unstructured grid has been developed that honors the geological structure precisely, enables accurate property modeling in a flattened, un-faulted, pseudo-depositional space, and can be simulated directly in a next-generation simulator; we call this unstructured grid built in depositional space a ‘depogrid’. The polyhedral, cut-cell nature of the depogrid arises when the regularly gridded volume in depositional space is cut by the structural model features (faults and unconformities) before being forward-deformed into geological space. By construction, the grid cell columns are orthogonal to the local stratigraphy, yet they can accurately represent complex structures and volumes, independent of the grid resolution. A next-generation high resolution reservoir seamlessly consumes the globally unstructured grid topology, with the structural complexity and non-neighbor connections, and honors the flow dynamics accurately. This ensures a more geologically consistent simulation model, realistic parameters to tune for history matching workflows and the ability to make reliable predictions.
We present some particular reservoir modeling and simulation considerations where the depogrid approach improves on typical gridding technologies. The seismic-to-simulation workflow is then applied to several structural examples to demonstrate how the depogrid is best suited to model the geological structure and properties in a variety of reservoirs and subsequently improves the accuracy and efficiency of field development planning and risk mitigation.
Present Day Softskills Needs and Views – 2017 SPEI Survey Results
Authors: Cheung Steve , Rijken Peggy , Agbor Etta 
Published: October 2018

Abstract
This paper documents the results from a SPEI survey that was distributed in October 2017 to gauge the members’ Softskills needs and preferences. We received approximately 1100 responses from 72 countries. This paper shows the survey statistics and shares the actions the SPEI Business Management and Leadership Committee (BML) (previously known as the Softskills committee) will consider in response to the survey results.
Coupled Fluid Flow and Geomechanical Modeling of Seismicity in the Azle Area North Texas
Authors: Chen Rongqiang , Xue Xu , Yao Changqing , Datta-Gupta Akhil , King Michael J. , Hennings Peter , Dommisse Robin 
Published: October 2018

Abstract
A series of earthquakes was recorded along a mapped fault system near Azle, Texas in 2013. To identify the mechanism of seismicity, coupled fluid flow and geomechanical simulation is carried out to model fluid injection/production and the potential onset of seismicity. Sensitivity studies for a broad range of reservoir and geomechanical parameters are performed and the calibrated models are used to identify controlling mechanisms for seismicity in the Azle area, North Texas and its relationship to hydrocarbon production and fluid injection in the vicinity. Geologic, production/injection, and seismicity data are gathered to build a detailed simulation model with coupled fluid flow and geomechanics. Geomechanical simulation results are used to calculate cumulative seismic moment magnitude. Sensitivity analyses for injection well head pressure and earthquake data are performed over a range of reservoir and geomechanical parameters. Influential parameters are selected to perform a pareto-based multi-objective history matching of well head pressures and seismic moments.
Geomechanical interaction has significant impact on seismicity in the Azle area. Unbalanced loading (overall injection and production) on different sides of the fault generates accumulation of strain change, resulting in the onset of seismicity. Previous studies seem to have significantly underestimated the fluid withdrawal rates, almost by an order of magnitude. The equivalent bottom-hole fluid rate used in this study suggests a drop in reservoir pore pressure which is consistent with the BHP trends. Thus, pore pressure increases may not explain the seismicity near the Azle area, as indicated in previous studies. Instead geomechanical effects and strain propagation to the basement appear to be the dominant mechanisms. The low fault cohesion and minimum horizontal stress obtained from history matching suggest that the faults must be near or at the critically-stressed state before the initiation of fluid production/injection. A sensitivity analysis indicates that the minimum horizontal stress and fracture gradient each play a critical role in the potential risk for seismicity related to fluid injection/production. Streamline flow pattern further proves that there is no fluid movement in the basement formation and the unbalanced loading from different sides of the fault is the controlling mechanism. This is the first study coupling fluid flow and geomechanics in the Azle area and the first to simultaneously calibrate the models with fluid flow and seismicity data.
Lunar Drilling – Challenges and Opportunities
Authors: Sawaryn S. J. , Bustin P. , Cain M. G. , Crawford I. A. , Lim S. , Linossier A. , Smith D. J. 
Published: October 2018

Abstract
Plans are being developed to drill and core a 100m deep hole on the Moon, an ambitious step beyond the 2.986m depth achieved at the Apollo 17 landing site in 1972. There are many scientific reasons for doing this, including determining the lunar geology and mineralogy below the meteorite-shattered regolith surface and its volatile content and heat flow, and identifying resources for future human space exploration. The complexities are such that the mission lead time is 15 plus years.
Drilling in the lunar environment poses many different technical challenges compared with terrestrial activity, although there are parallels, starting with the geological prognosis, similar to an oilfield exploration play. Operationally, the drilling equipment must escape Earth's gravitational pull. It must then travel almost 400,000 km to the drill site before it can be deployed and drilling starts. With each Kilogram of payload currently costing over $1.2 Million (Astrobotic Payload User Guide) this limits the available continuous power to approximately 100W, a minute fraction of its terrestrial counterparts. At these distances a radio signal takes 2.5 seconds to make the round trip, so the deployment and subsequent drilling activities must be largely autonomous. To add to the difficulties, the Moon's gravitational pull is only one sixth that of the Earth and it has no atmosphere, introducing weight on bit and hole cleaning problems. Despite the low gravity, displaced solids can still fall and obstruct the hole and some form of casing will be needed to secure the hole as it is drilled. The associated weight, power and geometrical limitations make this another serious technical challenge that must be overcome. With little or no chance to intervene, the operation must aim to be engineered to be right-first-time.
In the last decade, automation in oil and gas drilling has advanced considerably (Veila 2016; Hseih 2017). The number of autonomous activities has expanded and system reliability has improved. This, and other aspects of oil and gas experience, coupled with space exploration expertise and technology will be combined to make this happen. The pay-back for the oil and gas industry's involvement in this endeavor will be a step change in reliability and efficiency that results from satisfying the demanding conditions and clinical attention to detail that will be necessary to succeed.
The paper contains details of the goals, challenges and current thinking that drilling on the Moon entails, and the parallels with oil and gas drilling. This comes at a time when there is a renewed interest in further exploration of our solar system, particularly the Moon and Mars.
Assessment of a Barrier Integrity Violation Risk Using an Integrated 4D Reservoir Geomechanics Study
Authors: Sadykov Lenar , Korelskiy Evgeny , Samohvalov Andrey , Kostina Anna , Mamedov Elmin , Khromova Elizaveta , Zhelezova Anna , Shtun Sergey Yu. , Alexeev Andrej G. 
Published: October 2018

Abstract
Hydrogen sulphide represents an undesirable component of hydrocarbon reservoir fluids and its presence poses not only a significant risk for health and life of a personnel involved in hydrocarbon production and transportation, but also may drastically affect the field development strategy and economics, especially in an offshore environment.
The paper demonstrates the results of an assessment of risk of a hydrogen sulfide-containing gas breakthrough into the upper reservoir during its development at one of the fields of the Caspian oil and gas province. The assessment was performed using a coupled reservoir geomechanics modeling that allowed to estimate the changes in in-situ stresses state with field development. During production, differential and non-uniform pressure changes, caused by different depletion levels, result in differential deformation due to the change in effective stress, leading to reservoir rock failure, reservoir compaction and ground surface subsidence. Excessive localized deformation may also result in potential issues in cap and underlying rock integrity and fault seals.
A comprehensive mechanical core testing was carried out to correctly describe the rock failure criteria, which revealed the behavior of upper-layer cavernous carbonates similar to the behavior of the chalk formations of the North Sea, which are known to be prone to significant compaction during field development (J.P. Johnson et al, 1988).
Gas Adsorption Modeling in Multi-Scale Pore Structures of Shale
Authors: Zhang Yizhong , Wang Xiangzeng , Yao Shanshan , Yuan Qingwang , Zeng Fanhua 
Published: October 2018

Abstract
Shale pore space has a wide distribution of sizes (nm-μm) and complex configurations. Better knowledge of gas adsorption characteristics in real pore space is crucial for estimating shale gas-in-place. We develop a novel methodology to accurately and effectively calculate gas adsorption isotherms in multi-scale pore networks that simulate real pore structures inside shale. The influence of water saturations (in kerogen and clay) and pore distributions on gas adsorption is examined with our new model. 3D pore networks which connect both mesopores (2-50nm) and macropores (&gt;50nm) are developed based on 2D SEM images and mercury intrusion analysis. Interparticle pores and pores inside kerogen have different morphologies from the pores in clay agglomerates in our pore networks. The gas adsorption on each dry pore/throat's surface is realized by capillary condensation with the Kelvin equation, which relates capillary condensation to pore/throat structure, different solid (clay and kerogen) surface characteristics and fluid properties. Moreover, we use the gas-liquid Gibbs adsorption model for gas adsorption on wet solid surfaces with water present, which is not considered in the literature. 3D pore networks and nitrogen adsorption isotherms are generated for the Silurian Longmaxi Formation shale samples. The simulated nitrogen adsorption isotherms are comparable to adsorption test results. The comparison confirms that both accurate adsorption modeling on pore surfaces and reliable pore space reconstruction are important for designing and analyzing adsorption measurements. Sets of methane adsorption isotherms are further calculated on different pore networks. Each pore network is assigned a unique combination of clay content, total organic carbon content and pore size distribution (PSD). When the pore volume is constant, shale has higher adsorption amount of methane with decreasing pore sizes. When the water saturation increases, water will first occupy the void space in clay from small pores to large pores and then extend to pores inside kerogen. It is concluded that the adsorption amount of methane could be significantly reduced by 50% when water saturation in pore space increases from zero to 30%. Different from previous adsorption modeling studies on single dry pore/throat or a bundle of dry tubes, this study considers the adsorption modeling on a pore network that connects pores and throats with different sizes, wet or dry surfaces and various morphologies. This methodology and simulation results are reliable and effective for fundamental study and field performance estimation of gas adsorption in shale reservoirs.
Geomechanical Modeling Under Industry Standards
Authors: Cheremisin Aleksandr , Petrakov Yuri , Sobolev Aleksei , Stishenko Sergei , Tatur Olga , Chettykbaeva Kamilla , Ocheretyanyy Anton 
Published: October 2018

Abstract
Geomechanical modelling is widely applied in projecting oil and gas field development. Geomechanics are essential to three basic approaches: supporting oil and gas wells drilling in order to reduce the risk of hole instability (one-dimensional geomechanics).an adequation of effective stress of the reservoir occurs in the process of oil and gas field development. Stress condition changes modelling allows to consider their influence on the development parameters (three-dimensional geomechanics).preparing FRAC design and subsequent forthcoming debit appraisal.
Despite the wide expansion of geomechanical modelling some oil and gas producers do not apply it, considering it useless waste of resource. Even though vast experience shows that conducting certain research programs and developing geomechanical models can considerably increase drilling and development process efficiency. Furthermore, laboratory test and calculation expenses are materially lower than potential losses. But implementing new technology (geomechanical modelling in particular) to efficient oil and gas production processes is not always simple since it is necessary to justify the currentness of additional expenses and unevident profit.
Apart from the difficulties in slow implementation there is a variety of new companies that offer geomechanical modelling service. Each company offers its own approach to core examination, to specifying necessary number of samples and to the process of modelling. The customer has to choose the optimal technology of geomechanical modelling. Still the methodological basis of core examination must be settled plainly.
Therefore geomechanical modelling, an essential element of field development project documentation, has no standards or regulations which makes it hard to evaluate the prediction calculations.
The study addresses the question of necessity of regulation/standardization in geomechanical modelling at the government level (as with regulating the development plan and the calculation of reserves).
Early Kick Detection Using Adaptive Analytics with Downhole Accelerometer Data
Authors: Samuel Robello 
Published: October 2018

Abstract
High frequency downhole vibration data includes more hidden information than low frequency surface data. This paper discusses monitoring high frequency acceleration data for early kick detection because the accelerator sensor values’ trend is monitored rather than processed.
When gas, fluid, or oil kick occurs, fluid influx reduces fluid viscosity in the annulus, causing degradation of the damping factor. The sensor installed on the drillpipe detects the velocity/acceleration modification, resulting in the damping factor modification and includes an analytical model to calculate the effect of the damping ratio on the acceleration calculations. Fluid influx and migration in the wellbore strongly affects the damping factor.
This paper discusses a method of deconvoluting sensor values that use a combination of minimum entropy deconvolution and the Teager-Kaiser energy operator to remove the noise, unwanted sensor values, and the likelihood of false predictions. The trend of the final intrinsic mode functions (IMFs) at each depth is continuously monitored to predict formation influx, if any. A novel concept of monitoring incremental IMF and IMF energy at each depth is introduced, revealing a wealth of information and simplifying the process of monitoring and analyzing the vast amount of available data. The methodology developed extracts essential information from high frequency vibration data to make real-time data monitoring straightforward, reliable, and fast.
Drilling Performance Improvement in Marcellus Shale Play: A Case Study of Successful Implementation of Real-Time Digital Solution
Authors: Rimmey Andrew , Han George , Poojari Asha , Atwal Harnam 
Published: October 2018

Abstract
Most US onshore shale operators work with extremely limited budgets to be profitable in a low margin, low oil price environment. There is a significant emphasis on footage drilled per day, with solutions like better well plans, drill bits, and innovative bottom-hole assemblies (BHA). However, the smaller activities that add up to achieve higher footage per day include weight to weight (W-W) and connection times. The traditional ways to measure these key performance indicators (KPIs) and identify operational inefficiencies are manual, time consuming and after-the-fact.
To increase the overall drilling performance even with proven BHAs, an operator in Marcellus Shale leveraged a web-based application using industry-standard wellsite information transfer standard markup language (WITSML) protocol for automatic real-time drilling performance KPI monitoring and advisory services to focus on standardizing and reducing the W-W time. Weight to Weight time was divided into weight to slip (W-S), slip to slip (S-S) or connection times, and slip to weight (S-W) times to analyze trends and practices during the drilling process. The study focused on average W-W time improvement, and operational consistency on two rigs while drilling 32 wells from seven pads.
During this continuous improvement process, the operator identified best crew performance using automated crew comparison KPIs and disseminated best practices among the crews. At the end of the study, one rig W-W goal attainment rate increased by 50%. The operator also worked with the rig contractor to shuffle the rig crews by including the competent personnel from the most-efficient rig crew to the less-efficient rig crew to accelerate the sharing of best practices. This approach led to a 19% improvement of average W-W time over the course of the drilling campaign, and improved overall drilling performance. The best well was used for benchmarking and updated throughout the drilling campaign for continuous improvement of drilling performance.
Digital technologies combined with existing proven downhole technologies can help identify operational inefficiencies. Operators that use remote operations centers for planning, execution and risk reduction can benefit from real-time monitoring of drilling KPIs by taking timely and proactive measures.
Cost Reengineering
Authors: Maksimov Yuri , Skudar Oleg , Yanina Irina , Pashkevich Lev , Sandler Ilya , Ulyaschenko Vladislav 
Published: October 2018

Abstract
This article presents the method developed by Gazprom Neft to systematically improve efficiency of reserves of mature assets through the use of automated and integrated modules designed for comprehensive calculation of surface infrastructure construction and maintenance costs. A new and relevant for the oil and gas industry term – cost reengineering is suggested and its definition is given.
Best practices of cost engineering/reengineering are tested within the framework of some integrated reengineering projects implemented at Gazprom Neft's petroleum fields. The automation of the capital and operating costs estimation process contributed to the rapid consideration of a significant number of production optimization scenarios, and the high degree of decomposition of cost items and their formation parameters made it possible to manage costs in the context of individual elements of field infrastructure facilities.
The result of the efforts made by the multidisciplinary team was the development of a step-by-step workflow for reengineering projects which allows, in a systematic and integrated manner, to identify constraints and form the matrix of optimization measures.
Core Cleaning and Aging Effects of Devonian Carbonate Core at Micro Scale
Authors: Kovalev Kirill , Rashkovskiy Alexander , Khayrullin Marsel , Grishin Pavel , Shklover Vladimir , Artemov Nikita , Maryasev Igor 
Published: October 2018

Abstract
A carbonate core from Timan-Pechora oil and gas province study of some core cleaning and aging procedures on composition and structure of a pore space-mineral fringe are an important task for reserves evaluation and oil recovery modeling. Oil mineral skeleton interaction at micro scale characteristics provided by modern methods of electron microscopy and spectroscopy, that have allowed to extend a traditional petrophysic core data of reservoir properties and wettability. The Devonian Timan-Pechora carbonates hydrocarbon films and chemical bonds analysis novel data was obtained by a XPS technique taking into account pore volume structure, films microscopic structure and chemical behavior at calcite mineral surface. Carbonate rock cleaning and aging procedures impact was carried out.
The evaluation of the influence of the extractant type on the intensity of the impact on the rock and the regimes of aging and storage of the core on the microstructural parameters of the sorption of hydrocarbon films on the surface of the void space made it possible to develop recommendations for preserving the character of the wettability of the initially hydrophobic carbonate rocks for further petrophysical experiments and the development of an EOR. The hydrophobic carbonates wettability characteristic preservation recommendations proposed basing on hydrocarbon films microstructure sorption on mineral surface parameters. A water hydrophobic carbonate rock interaction conclusions were proposed basing on data correlation about carbon chemical bond types, microstructural studies, water microdrops dynamic condensation on rock surface analysis combined with reservoir properties and pore volume distribution parameters about the hydrocarbon films sorption and impact. This type of rocks data clarifying practices for EOR forecasting proposed.