bluuebunny/crossref_metadata_2025_split huggingface dataset:
Deriving Reservoir Net Pay Cutoffs from Mercury Injection Tests and Routine Core Analysis
Authors: Shi Xinlei , Lv Hongzhi , Li Xingli , Cui YunJiang , Li Ting 
Published: October 2018

Abstract
The net pay cutoffs are the critical parameters in calculating the total pay thickness and estimating hydrocarbon reserves. To determine these parameters, the industry has been largely relying on drill stem tests (DST) or downhole fluid samplings, which provide information on the productive capacity of different pay intervals. However, due to the high operational cost, these measurements are typically quite scarce, particularly in offshore oilfields. In complicated reservoirs where hydrocarbon viscosity shows vertical variation, the net pay cutoffs change as well and hence even more measurements are required to accurately characterize the changing cutoffs.
In this paper, we propose a novel workflow to derive the porosity and permeability net pay cutoffs by integrating core Mercury Injection for Capillary Pressure (MICP) test and core porosity and permeability, therefore reducing the need for costly DST and sampling. Our core dataset consists of 1024 rock samples, among which 529 have MICP test data. These samples come from 14 oilfields in Bohai Bay where the operator has some local knowledge of the porosity and permeability cutoffs, as well as the oil viscosity. In general, the porosity and permeability cutoffs discovered through testing have a poor correlation with oil viscosity.
Using our core dataset, we built a localized Winland equation relating the apex pore throat aperture (Rapex) to core porosity and permeability. With this equation, we translated porosity and permeability cutoffs into Rapex cutoff. Our study shows that Rapex cutoff has a much better correlation with viscosity than porosity cutoff and oil density. Based on this finding, we developed the following workflow to accurately predict porosity and permeability net pay cutoffs from oil viscosity using Rapex as a guide: For all rock samples, graphically find the apex aperture radii on the corresponding MICP curves.Using regression, find customized Winland equation relating Rapex to core porosity and permeability.For oilfields where the porosity and permeability cutoffs are well defined, calculate Rapex cutoff corresponding to porosity and permeability cutoffs using the equation in step 2. Plot oil viscosity against Rapex cutoffs in a chart and fit an exponential function to the sample points.For new oilfields with known oil viscosity but unknown net pay cutoffs, we enter the oil viscosity into the chart in the previous step and read off the Rapex cutoff value from the regression line.Draw the porosity and permeability values corresponding to the Rapex cutoff in a poroperm plot using the equation in step 2, and draw the core porosity and permeability points from the field under study as overlay. The porosity and permeability net pay cutoffs can be found at the intersection of the core points and the Rapex line.
The porosity and permeability cutoffs found using Rapex cutoff are highly consistent with those found by actual DST or samplings.
Upconversion Nanoparticles as Tracers for Production and Well Monitoring
Authors: Murugesan Sankaran , Agrawal Devesh , Suresh Radhika , Khabashesku Valery , Darugar Qusai 
Published: October 2018

Abstract
Luminescent upconversion nanoparticles are used as alternate fluorescence tracers to overcome the interference of organic molecules in the analysis of flowback waters. Upconversion nanoparticles use low-energy excitation at approximately 980 nm with high-energy emissions in the region of 200 to 950 nm. Emission properties of the nanoparticles are tuned by selective doping, and their dispersiblity in water and oil are altered through appropriate functionalization. The flow experiments used stable crude oil emulsions in API brine with the mixture of two different emission upconversion tracer nanoparticles. Data from these experiments suggest that the nanoparticle tracers can flow through the porous media and distinguish between each other, even in the presence of organics in an emulsion. This capability can open new avenues in in-situ reservoir communication and understanding.
Big Data Analytics for Seismic Fracture Identification, Using Amplitude-Based Statistics
Authors: Udegbe Egbadon , Morgan Eugene , Srinivasan Sanjay 
Published: October 2018

Abstract
Present day innovations in seismic acquisition tools and techniques have enabled the acquisition of detailed seismic datasets, which in many cases are extremely large (on the order of terabytes to petabytes). However, data analysis tools for extracting information on critical subsurface features such as fractures are still evolving. Traditional methods rely on time-consuming iterative workflows, which involve computing seismic attributes, de-noising and expert interpretation. Additionally, with the increasingly widespread acquisition of time-lapse seismic surveys (4D), there is a heightened demand for reliable automated workflows to assist feature interpretation from seismic data.
We present a novel data-driven tool for fast fracture identification in BIG post-stack seismic datasets, motivated by techniques developed for real-time face detection. The proposed algorithm computes spatiotemporal amplitude statistics using Haar-like bases, in order to characterize the seismic amplitude properties that correspond to fracture occurrence in a unit window or voxel. Under this approach, the amplitude data is decomposed into a collection of simple-to-calculate "mini-attributes", which carry information on the amplitude gradient and curvature characteristics at varying locations and scales. These features then serve as inputs to a cascade of boosted classification tree models, which select and combine the most discriminative features to develop a probabilistic binary classification model. This overall approach helps to eliminate the computationally-intensive and subjective use of ad-hoc seismic attributes in existing approaches.
We first demonstrate the viability of the proposed methodology for identifying discrete macro-fractures in a 2D synthetic seismic dataset. Next, we validate the approach using 3D post-stack seismic data from the Niobrara Shale interval within the Teapot Dome field. We show the applicability of the proposed framework for identifying sub-seismic fractures, by considering the amplitude profile adjacent to interpreted fullbore microimage (FMI) well log data. The upscaled spatial distribution of the predicted fractures shows agreement with existing geological studies and align with interpreted large-scale faults within the interval of interest.
Capping Stack Technology Comes of Age
Authors: Cuthbert Andrew 
Published: October 2018

Abstract
While several years have passed since the 2010 Gulf of Mexico (GOM) source control incident that caused a six-month drilling moratorium, the industry likely believes it is fully prepared to prevent or mitigate the effects of a similar incident in a timely manner. However, installing a source control device on a blowing well is a technically complex exercise, one that has never been performed; while performing such an operation, one should consider challenges posed by metocean conditions, coupled multiphase hydrodynamics, and multibody interactions that complicate the deployment and docking of a capping stack onto a subsea wellhead.
The latest gate-valve technology intended to close against flow presents a more compact option for rapid capping than unwieldy ram-based systems. The speed of deployment of the lighter capping stack is attributed to the availability of suitable aircraft, lifting equipment at the airport or dockside, and an ample supply of suitable deployment vessels. The underlying logistical issues that prevent rapid responses to subsea incidents have not, for the most part, been addressed until now. A development differentia in capping-stack technology has been necessary to exact the speed of response that the industry calls for and to meet the expectations of stakeholders and the general public. Fortunately, the industry now has access to technology that can be deployed to a source control incident in any global location in a matter of days.
Sophisticated, high-fidelity simulation, hitherto unavailable, incorporates metocean sea state and uses coupled multiphase hydrodynamics and multibody interaction effects of vessel motion, suspension system dynamics, and the hydrodynamics of the capping system within the unstable blowout forces to create an accurate analysis that addresses plume and landing-force analysis at the wellhead. Coupled with the tools to accurately simulate the effects of the force dynamics from surface to wellhead to complete the entire process, the advances accompany the new capping design and enhance the ability to determine landing capability, heralding further advancement in source control technology and techniques.
Case Studies in Deriving Holistic Insights from an Automated Drilling Optimization Platform
Authors: Vempati Chaitanya , Dolezal Tisha 
Published: October 2018

Abstract
The last decade has seen a tremendous increase in the use of oilfield data to understand problems of well construction, evaluate drilling performance and derive guidance on future drilling. Despite the tremendous increase in investment and application of various data mining techniques, the outcomes in the well construction domain have been subpar when compared to that of other industries. Yet analysis of drilling data has resulted in useful predictions on the small scale–comparing a few wells where the huge number of variables that influence drilling (formation, rig, bottomhole assemblies [BHA], etc.) have little fluctuation. However, making actionable predictions on a much greater scale, and in the presence of significant variability, is substantially more challenging. The authors introduce a new platform for automated drilling analysis and optimization. The system starts with an enhanced in-bit measurement device that enables an improved view of downhole conditions at a higher density. This data is then tied to surface measurements through robust data validation and streamlined capture of variables. Finally, the platform ties state-of-the-art, physics-based models, which capture the physics of drilling from cutter-rock interface, to power delivery from the rig through the BHA to quantify the influence of each variable. This coupling of physics-based modeling and models based on drilling data is used to deliver key holistic insights–not just on speed of drilling, but also balance it against borehole quality, efficiency and health of the tools. Results of this new optimization platform, which was tested in the SCOOP and STACK plays of Central Oklahoma, are presented in this paper. The platform shows the power of combining physics and measured data to detect hidden insights, derive actions and enhance drilling performance.
A New Transient Model to Simulate and Optimize Liquid Unloading with Coiled Tubing Conveyed Gas Lift
Authors: Han Guoqing , Ma Gaoqiang , Zheng Jian , Gao Yue , Zhang He , Ling Kegang 
Published: October 2018

Abstract
Nowadays, unloading gas wells with coiled tubing is a common application to the field. However, it still lacks of adequate understanding of dynamic behavior of the unloading process. This paper investigates the process of liquid unloading by gas lift with coiled tubing under transient condition. This unloading process can be divided into three stages: liquid rising in tubing, liquid slug production, and liquid production by entrainment. In each stage, the mass and linear momentum conversation equations are applied as governing equations. The components of each stage includes coiled tubing, coiled tubing-tubing annulus, liquid slug, gas bubble, and liquid film. Empirical correlations have been used including surface gas injection choke, check valve, friction factor, the relationship between the gas bubble and the liquid slug velocity, inflow performance relationship, and blackoil fluid properties. From the above, the dynamic model coupling real-time change of inflow performance relationship. Using the LU factorization and Euler's method to solve the proposed dynamic model in time domain. Among all these variables, the most important ones include gas injection rates, pressures at various locations, length of the liquid slug and gas bubble, and various velocities. By the simulation efforts, the mechanism of liquid unloading process is revealed.
Gas lift is commonly constrainted by gas availability. This is pioneer study on liquid unloading with coiled tubing is critical in design phase to optimize the usage of injected gas as well as choose appropriate pump and cost-saving for electricity expense.
Microemulsion Effects on Oil Recovery from Kerogen Using Molecular Dynamics Simulation
Authors: Bui Khoa , Akkutlu I. Yucel , Zelenev Andrei S. , Hill W. A. , Griman Christian , Boudreaux Trudy C. , Silas James A. 
Published: October 2018

Abstract
Source rocks contain significant volumes of hydrocarbon fluids trapped in kerogen, however their effective recovery is challenged due to amplified fluid-wall interactions and the nanopore confinement impact on fluid composition. Enhanced oil production can be achieved by modifying the existing molecular forces in kerogen pore-network by using custom-designed targeted chemistry technologies. Our objective is to show how the transport of hydrocarbons in kerogen and its recovery can be altered with the delivery of microemulsion nanodroplets into the pore network. This is done by using computational chemistry and molecular dynamics (MD) simulations.
Molecular dynamics simulation is used to generate a 3D model replica of a Type II kerogen representative of source rocks located in Delaware and Midland basins in the United States. Oil phase saturated kerogen is modeled as consisting of nine different types of molecules: dimethyl naphthalene, toluene, tetradecane, decane, octane, butane, propane, ethane and methane. The delivered microemulsion is an aqueous dispersion of solvent-swollen surfactant micelles. The solvent and nonionic surfactant present in the microemulsion are modeled as d-limonene and dodecanol heptaethyl ether (C12E7), respectively. Molecular dynamics simulation experiments include two steps: (i) the injection of microemulsion treatment fluid into the oil-saturated kerogen pore-network, and (ii) transient flow-back of the oil-chemical mixture in the pore network. The utilized 3D kerogen models were developed based on a representative oil sample composition (H, C, O, S, N) from the region. Simulation results show that microemulsions can affect the reservoir via two different mechanisms. During the injection, microemulsion nanodroplets that enter the nano-capillaries of pore network disperse in the liquid present in the pore space under the influence of pore walls. The solvent dissolves in the oil phase and alters the physical and transport properties of the phase, while the surfactant molecules modify the wettability of the solid kerogen surfaces. The recovery effectiveness of heavier oil fractions is improved compared to the recovery effectiveness achieved with surfactant micelles without the solubilized solvent.
New 3D kerogen models are presented using atomistic modeling and molecular simulations. These models possess important chemical and physical characteristics of the organic matter of the source rock. Molecular dynamic experiments indicate that solubilized solvent and surfactant are delivered as part of a microemulsion droplet and are expected to aid the mobilization of oil present within kerogen.
Far-Field Diversion Technology to Prevent Fracture Hits in Tightly Spaced Horizontal Wells
Authors: Vidma Konstantin , Abivin Patrice , Dunaeva Anna , Panga Mohan , Nikolaev Max , Usoltsev Dmitriy , Mayo JT 
Published: October 2018

Abstract
More than 60% of US land wells drilled in 2017 are infill wells. Fracturing in such wells is likely to cause fracture hits on adjacent wells, which may have a negative impact on the infill and nearby existing well production. A new technology has been developed to control the geometry of the fracture, which reduces significantly the fracture hit rate and increases production in the child (infill) and parent wells.
Traditional methods for controlling the geometry of hydraulic fractures include adjusting pad and proppant volumes and fluid viscosity. The proposed technology uses an alternative approach, delivering a multimodal particulate diversion mix with the proppant. The job is designed so that the diversion mix bridges and accumulates at the fracture tip, thus confining the fracture perimeter and controlling fracture length growth.
The proposed technology has been field tested in 11 wells (219 stages) in the Eagle Ford shale. The results showed high efficiency of fracture hit prevention (84% of stages free of fracture hits) and increased production in the child and parent wells. The technology showed high operational reliability, (no premature screenouts) and was proven to be cost effective and robust. Laboratory experiments were conducted to tailor the permeability of the diversion blend. Because the diversion blend contains very small particulates, a wellsite delivery method was developed to prepare the blend and deliver it safely. Guidelines for the diverting pill pumping schedule were developed to optimize fracture hit prevention.
The developed technology demonstrates that the complicated process of fracture growth geometry correction can be performed with intelligent engineering design including a far-field diversion pill.
Application of Hollow Fiber Membrane Contacting System for CO2/CH4 Separation
Authors: Ghobadi Jalil , Ramirez David , Khoramfar Shooka , Jerman Robert , Crane Michele , Oladosu Olufemi 
Published: October 2018

Abstract
Carbon dioxide separation using membrane based contacting system is a reliable alternative to traditional gas absorbent techniques such as wet scrubbers. The main objective of this research was to design, develop and implement a hollow fiber membrane based contactor system to absorb and separate CO2 from CH4 in a simulated flare gas stream.
Gas-liquid contacting system was constructed using microporous polytetrafluoroethylene (PTFE) hollow fibers as a highly hydrophobic membrane. The module used for the experimental studies has 51 mm diameter and 200 mm effective length. The membrane module had the packing density of 60 % and the PTFE hollow fiber being employed in this module had the mean pore size of 0.48 μm. Experiments conducted in a laboratory-scale plant fed with a simulated flare gas mixture containing 2.5 % of CO2 balanced with CH4 which could produce varying concentrations of inlet gas using mass flow controller.
CO2 separation experimentation studies were performed and effect of operational variables on separation efficiency of the system has been studied. In order to optimize the gas separation performance of the membrane module, effects of gas and liquid flow rates, absorbent-phase concentration, and nature of scrubbing liquid were examined. The absorption efficiency of deionized-water and aqueous solutions of sodium hydroxide (NaOH) and diethanolamine (DEA) as the physical and chemical absorbents has been compared. Results indicated that increasing the flow rate and concentration of scrubbing liquid can enhance the separation efficiency; however, increasing the flow rates of the gas-phase has a negative impact on the CO2 absorption performance of the system.
The traditional CO2 separation process suffers from many limitations, such as high capital and operational costs, and potential of equipment corrosion. Membrane processes offer attractive opportunities for gas treatment applications including removal of CO2, H2S, and SO2 from flare gas mixtures. This technology offers a variety of practical benefits including low energy and operation costs and at the same time it can help to mitigate the adverse health effects associated with burning the waste gases.
Implementing Blockchain Technology in Oil and Gas Industry: A Review
Authors: Lakhanpal Vikrant , Samuel Robello 
Published: October 2018

Abstract
The oil and Gas industry has recently transformed itself into a data-intensive industry – artificial intelligence, machine learning and internet of things. With such growth and expansion, distributed ledger technology, commonly known as blockchain, can carry the industry's transformation forward. This technology can help the industry to overcome various challenges such as price volatility, supply chain, accounting, data management and security. It can also help in streamlining various engineering and technical decisions.
Technologically, the oil and gas industry has been very innovative – 3-D seismic, hydraulic fracturing, geosteering, imaging beneath salt, etc. However, the administrative and managerial functions are still done in a somewhat traditional way. The Blockchain technology can help the industry become more efficient by streamlining these traditional methodologies.
This paper presents the four major areas where the blockchain technology can help the industry overcome various day to day challenges – (1) Supply Chain and Trading, (2) Regulatory, (3) Database Management and (4) Cyber Security.
Like any new technology, the blockchain technology might not get a full embrace at the beginning, but the idea is to present a qualitative study about its benefits. The industry currently has little or no knowledge about this technology, which is expected to bring transparency, security and convenience in one place. The objective of this paper is to help the industry peers understand the idea behind this technology and how it can transform the way the industry currently operates. It provides a frame of reference for the industry to realize the potential of this technology and assess its benefits.