bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Practical Approach to Casing Wear Prediction, Modeling and Mitigation on Challenging ERD Wells
Authors: Dai Weifeng , Noel Brian , Alvord Chip , Njoku Johnson , Hopper Joey , Smith Lee 
Published: October 2018

Abstract
Casing wear caused by rotating drill strings can lead to reduced well life, failed or burst casing strings, and expensive non-productive time (NPT) for remedial actions. In Alaska's Alpine Development field, where logistics are challenging, regulations are strict, and the operational window is small, drilling increasingly long laterals has vastly increased the cost and risk of casing wear, necessitating effective mitigation.
After detailed analyses of Alpine field wells, one operator successfully implemented a casing wear mitigation plan combining new tools, modeling techniques and analyses. The plan required strategic placement of Non-Rotating Protectors (NRPs) based on predicted casing wear, analyzed side forces, and lateral length. Additionally, the operations group wanted to simultaneously improve computer modeling for both casing wear and torque and drag (T&D) analysis.
One major challenge was predicting appropriate wear factors for casing wear modeling. Operational challenges included how to deploy the plan in managed pressure drilling (MPD) operations, where preventing premature wear on rotating control device (RCD) sealing elements had to be considered.
Implementing this casing wear mitigation plan allowed the operator to successfully drill extended reach multilateral wells to planned total depth while keeping wear below maximum allowable thresholds. The paper describes the challenges and approach to predict casing wear, as well as successful mitigation strategies and lessons learned from an extensive offset database. Included are comparisons to field results from casing logs, and several wells that deployed the casing wear mitigation plan, versus an offset well that was drilled without a plan.
The paper describes new techniques for predicting and modeling casing wear which, in combination with utilization of specific tools, results in a readily-applicable approach to wear mitigation in extended-reach drilling (ERD).
An Experimental and Simulation Investigation on the Effect of Different Gas Mixtures on Performance of Miscible CO2 Injection in HPHT Abu Dhabi Reservoir
Authors: Alshuaibi Muataz , Farzaneh Seyed Amir , Sohrabi Mehran 
Published: October 2018

Abstract
The carbon dioxide flood represents one of the proven enhanced oil recovery methods. However, there are significant challenges associated with applying CO2 flood in onshore or offshore reservoirs. One of the common problems is a limited supply of CO2. Therefore, recycling and re-injection of the produced gas should be considered in many applications especially in the case of giant carbonate reservoir in the Middle East. In this work presented here, we performed a comprehensive series of slim-tube and phase-behavior experiments coupled with numerical simulation to explore the effect of the mixture of non- hydrocarbons and hydrocarbon gases with CO2 on the behavior and the performance of the gas flooding process.
This study involves a series of slim-tube experiments to identify the MMP of CO2 and different mixture of gases namely N2, C1, and C2. Moreover, mixing cell experiments were also performed to calibrate phase behavior models based on crude oil and injected gas interaction in a PVT cell. Furthermore, full compositional analysis of the produced oil and gas for both slim-tube and phase-behavior experiments were carried out to better understand the dominant mechanism of the injected gas at different conditions. Besides, the experimental results were employed as a benchmark against the numerical 1-D simulations which was based on the tuned EOS with advance PVT experiment's to predict the impact of different mixtures on the MMP.
The experimental results of CO2 with a different gas mixture of up to 20% were shown that the attribution of N2 and C1 in increasing the MMP in both dead and live oil systems and N2 has the highest impact on increasing the MMP. The results of the gas chromatography analysis of the produced gas clarified that there was an interaction between the injected gas and the crude oil in which a bank of immiscible light hydrocarbon gases created at the miscible front. The composition of C1 in the produced gas was decreased from 70% at CO2 BT to 31% at the end of the experiment. Therefore, when CO2 recycling was considered, the concentration of CO2 will be decreased, and miscibility between the oil and CO2 required much higher MMP. However, the CO2 extract oil components (C1 up to C30) which contribute to leaving heavier oil behind. The miscibility of remaining oil was achieved but at very high pressure due to the non-existence of light components. The results of 1-D slim-tube simulation have shown a promising result in predicting MMP of the performed experiments.
The result of the study demonstrated the potential of lowering the cost by design a mixture of CO2 with hydrocarbons and non-hydrocarbons gases instead of injection high purity CO2. Although, this study contributes to understanding the mechanism of the process of CO2 injection when recycling and reinjection are considered.
Design of Offshore Production Systems Considering Uncertainties
Authors: Sales Leonardo de , Morooka Celso Kazuyuki 
Published: October 2018

Abstract
The development of an offshore oil field is a complex and risky project. One core problem in this task is the selection of a production system that maximizes oil recovery and minimizes investments and operational costs while meeting external, economic, environmental, societal and technological demands in a scenario of uncertainties. Several studies address this problem in the literature; however, they do not consider uncertainties in the initial data neither justify objectively the chosen alternative among other feasible ones. We propose to select an offshore production system using an intelligent system that considers input uncertainties and chooses the best alternative in a rational manner. By comparing the results obtained with previous studies and real scenarios, we conclude that our methodology can obtain the optimal solution in situations where other methods cannot.
A Method to Measure Ultralow Permeabilities of Shale Core in Multiple Directions Using Pressure-Pulse Decay Technique
Authors: Yang Zehao , Bryant Steven , Dong Mingzhe 
Published: October 2018

Abstract
Permeability is a very critical tight reservoir parameter to characterize the process of oil/gas storage and production. In particular, distinct anisotropy of the shale reservoir, demands a practical method to measure permeabilities in multiple directions using the same core.
In this work, a systematic and practical pressure-pulse decay (PPD) technique is given to determine ultralow permeabilities of shale reservoir core in a cell with finite volume. The test gas can be non-adsorption gas such as helium or adsorption gas such as methane.
As described herein, given appropriate assumptions, the mathematical models based on the corresponding designed experiments (non-adsorption gas or adsorption gas) are formulated, and the exact solutions for the corresponding mathematical models are proposed using Laplace transform. Approximation techniques are further given to analyze experimental data to obtain radial and axial permeabilities. It is found that there are distinct anisotropy of shale reservoir and the permeability may be smaller when adsorption gas is used instead of non-adsorption gas.
Compared with traditional two-chamber PPD techniques, its advantages mainly lie in three points: only the pressure in one chamber is measured, which can lead to fewer pressure transducers and easier experimental operation. Meanwhile, the center of shale core needs not be drilled when the radial permeability is measured. What's more, the whole measurement is based on the same core and more information of the core can be obtained. However, it should also be noted that there is about 1 MPa difference of effective stress between our axial experiments and radial experiments. The effect of this difference on permeability is typically less than 5%, so the modified PPD can detect anisotropy efficiently.
Quantitative Integration of 4D Seismic with Reservoir Simulation
Authors: Ketineni Sarath Pavan , Kalla Subhash , Oppert Shauna , Billiter Travis 
Published: October 2018

Abstract
Standard history matching workflows use qualitative 4D seismic observations to assist in reservoir modeling and simulation. However, such workflows lack a robust framework for quantitatively integrating 4D seismic interpretations. 4D or time-lapse seismic interpretations provide valuable inter-well saturation and pressure information and quantitatively integrating this inter-well data can help to constrain simulation parameters and improve the reliability of production modeling. This paper outlines technologies aimed at leveraging the value of 4D for reducing uncertainty in the range of history matched models and improving the production forecast.
The proposed 4D Assisted History Match (4DAHM) workflows utilize interpretations of 4D seismic anomalies for improving the reservoir simulation models. Design of Experiments (DOE) is initially used to generate the probabilistic history match simulations by varying the range of uncertain parameters. Saturation maps are extracted from the Production History Matched (PHM) simulations and then compared with 4D predicted swept anomalies. An automated extraction method was created and is used to reconcile spatial sampling differences between 4D data and simulation output. Interpreted 4D data is compared with simulation output, and the mismatch generated is used as a 4D filter to refine the suite of reservoir simulation models. The selected models are used to identify reservoir simulation parameters that are sensitive for generating a good match.
The application of 4DAHM workflows has resulted in reduced uncertainty in volumetric predictions of oil fields, probabilistic saturation S-curves at target locations, and fundamental changes to the dynamic model needed to improve the match to production data. Results from adopting this workflow in two different deep-water reservoirs are discussed. They not only resulted in reduced uncertainty, but also provided information on key performance indicators that are critical in obtaining a robust history match. In the first case study presented, the deep-water oil field 4DAHM resulted in a reduction of uncertainty by 20% in OOIP and by 25% in EUR in the P90-P10 range estimates. In the second case study, 4DAHM workflow exploited discrepancies between 4D seismic and simulation data to identify features necessary to be included in the dynamic model. Connectivity was increased through newly interpreted inter-channel erosional contacts, and sub-seismic faults. Moreover, the workflow provided an improved drilling location which has the higher probability of tapping unswept oil and better EUR. The 4D filters constrained the suite of reservoir simulation models and helped to identify 4 out of 24 simulation parameters critical for success. The updated PHM models honor both the production data and 4D interpretations, resulting in reduced uncertainty across the S-curve and, in this case, an increased P50 OOIP of 24% for a proposed infill drilling location, plus a significant cycle-time savings.
Improved Reservoir History Matching and Production Optimization with Tracer Data
Authors: Chen Hsieh , Poitzsch Martin E. 
Published: October 2018

Abstract
Interwell tracers have been shown to provide invaluable information about reservoir dynamics, well connectivity, and fluid flow allocations. However, tracer tests are often applied sporadically because their immediate returns of investments are not readily apparent to a resource-holder. Here, we rigorously demonstrate that tracer data can indeed improve reservoir history matching, and, more importantly, improve future production, using reservoir simulations on benchmark problems. Sensitivity studies and the limitations of tracer data are also provided.
The numerical experiments were divided in two sections. First, production data with or without tracer data from reference fields were collected for the first water flooding periods for history matching. Second, the history matched models from the first section were used for production optimization for the next water flooding periods. The ensemble smoother with multiple data assimilation (ES-MDA) was used for the history matching processes for the first part of the numerical experiments, and the modified robust ensemble-based optimization (EnOpt) was adopted to maximize the net present value (NPV) for the second part of the numerical experiments.
The three-dimensional channelized "Egg Model" was chosen as the initial benchmark problem. From the first part of the numerical experiments, using the same hyper-parameters, it was observed that history matching including tracer data resulted in a better match of the field production rates with smaller standard deviations. In addition, history matching including tracer data resulted in more distinct geological features when observing the history matched permeability maps. From the second part of the numerical experiments, we observed that the geological models history matched including tracer data resulted in better production optimization with higher NPV produced. In the specific case of the Egg Model, +4.3% increase of the NPV was observed.
To understand the sensitivity and the limitations of the tracer data, the same numerical experiments were performed on a library of reservoir models with different fracture patterns. After the history matching and production optimization simulations, we observed that including tracer data gave positive NPV increases ranging from +0.3% to +9.4% from 5 of the 7 test cases. It was observed that tracers were more effective for the non-homogeneously flooded reservoirs.
To the best of our knowledge, this paper is the first study that quantifies the benefits of tracers in the context of the improved production, measured in NPV. In a broader perspective, we believe this is the best way to test any new history matching algorithms or reservoir surveillance methods. In this work, we show that tracers can result in positive NPV in most situations, and oil producers using large-scale water flooding operations would benefit from performing more tracer tests in their operations.
Enabling Collaborative Decision Making Through Immersive Visualisation
Authors: Helm Paul , Pickering Julian 
Published: October 2018

Abstract

Objectives/Scope
Virtual Reality (VR) and Augmented Reality (AR) are becoming increasingly popular in many industrial sectors but the uptake in oil and gas has, in comparison, been very modest. There is little doubt that these technologies will have a growing influence in our recreational lives over the next few years, as the hardware capability increases, costs decrease, and applications become more widely available. The real strength of these technologies is their capability to disseminate information to the user in a truly immersive experience. One area where this could be very valuable in our industry is in the support of drilling and production operations. Real-time Operations Centres (RTOCs) are now in widespread use but these suffer from high capital and operating costs, they are difficult and expensive to reconfigure and are often difficult to engage with from a remote location. Conversely, a Virtual Real-time Operations Centre (vROC) is low cost, can be configured quickly and decommissioned readily when no longer required. With modern networking configurations it is easy to connect from anywhere. This paper describes the first developments of a vROC.

Methods, Procedures, Process
A common understanding or shared situational awareness is essential for making the best operational decisions in the shortest possible time. This has been the main driver for the development of collaborative working and has resulted in the development of a wide range of work spaces ranging from smaller Collaborative Work Environments (CWEs) through to large scale RTOCs and interactive visualisation centres. The vROC replaces the need for the user to relocate to these physical areas. By deploying a 3D headset, they can enter the 3D virtual workspace and work with colleagues in true collaboration. This project has enabled data to be visualised within the workspace in the same way that it would be seen in a physical room with conventional display panels.

Results, Observations, Conclusions
This project is in the early stages of development, but it has shown already how quickly a vROC may be configured and populated with live and historical data from different sources. Using 3D CAD models, photogrammetric representations and other spatial data, process plants, reservoirs and wells can be brought into the vROC, annotated with real time data and experienced by all users. We have developed live trends and have animated models to highlight alarm situations.

Novel/Additive Information
At a time when operators need to minimise their operating costs whilst maintaining top performance the use of virtual work environments is likely to become a major contributor to cost savings.
Geological Heterogeneity in Geological Models - A Review of the Impact of Available Data, Modeling Parameters, and Modeling Workflow on Primary Recovery, Waterflooding, and Steamflooding Projects
Authors: Meddaugh W. Scott , Meddaugh Andrew J. 
Published: October 2018

Abstract
Reservoir modeling and the derived fluid production over time curves are a key part of the workflows associated with major capital project decisions. These models may be very complex and use a variety of geological constraints in an effort to develop the porosity, permeability, and saturation distributions used in dynamic models (with or without upscaling). Over time and partially in response to increased computing capability as well as the need for more realistically heterogeneous models, model size as measured by number of model cells and model complexity has increased but model-derived production forecasts remain optimistic. This paper, one of a series that now stretches back over a decade, addresses a number of modeling issues with the goal of (1) better understanding how modeling workflows may contribute to forecast optimism and (2) what reservoir modelers, both geologists and engineers, may do to reduce forecast optimism derived from their subsurface models by improved understanding of how model parameters such as grid size, number of grid cells, semivariogram parameters (e.g. the range), and number of geological/stratigraphic "control" surfaces used to constrain models. Adequate modeling of reservoir heterogeneity appears to require very to extremely large models (e.g. large number of small cells). Many of the parameters used to "control" heterogeneity including the semivariogram range parameter, the number of "detailed" stratigraphic layers, and the number of rock/facies "containers" or model regions appears to have only a small impact on forecast recovery.
Temperature Logging Guidelines and Factors that Affect Measurement Accuracy
Authors: Adnyana Gede , Sharma Jyotsna , Mims Don , Barnes David , Behrens Ron 
Published: October 2018

Abstract
A robust reservoir surveillance program is the key to successfully managing a steamflood operation. Observation wells allow us to directly monitor changing reservoir conditions throughout the life of the steamflood using time lapse surveys. Temperature surveys are a primary data type collected from the observation wells to evaluate the reservoir heating, and to monitor the steamchest. Thus, accurate measurement and proper interpretation of temperature surveys is essential for steamflood management.
The objective of this study was to look at factors that can impact a temperature log and steps that can be taken to improve temperature measurement accuracy. Several field examples are presented to illustrate the effects of logging speed, steamchest temperature, sensor type and wellbore fluid on recorded temperature data. Guidance on evaluating and interpreting different temperature signatures such as, interpretation of liquid level in an observation well, understanding temperature signatures in air, wellbore reflux phenomenon, and examples of logs from malfunctioning logging tools, are also provided. The main purpose of this work is to aid both the operators and the service companies to gather accurate temperature data for improved steamflood management. This study is based on an extensive study of field data, primarily gathered from a single company's steamflood operations in California (using over 1000 temperature observation wells). Additionally, an analytical model was developed based on reservoir heat transfer and the sensor response mechanism to understand the impact of steam chest temperature, logging speed and sensor response time on the accuracy of the temperature log data. Results from the analytical model support the field observations.
Field data and analytical assessment show that several factors can impact the accuracy of a temperature log, which can subsequently affect our interpretation and operational decisions. Data suggests that higher logging speeds introduce greater error in measured temperature data and these errors are greater at elevated steamchest temperatures. Temperature tools with longer sensor response times need to be run at slower logging speed to get accurate measurements. Ensuring adequate level of thermally equilibrated liquid (typically water) in the observation well is essential both, for gathering accurate data and to mitigate possible safety concerns for the logging operator. The examples and guidelines provided in this study will aid the practitioners to improve the gathering and interpretation of temperature log data.
Numerical Evaluation of Plastic Strains in Coiled Tubing Surface Flaws for Comparison to Analytical and Emperical Models
Authors: Kilambi Sreelatha , Tipton Steven M. 
Published: October 2018

Abstract
Coiled tubing (CT) endures cyclic bending strains on the order of 2 – 3% during its normal operation. Consequently, fatigue is the major factor limiting its useful life. Furthermore, CT is routinely subjected to gouges or defects due to harsh oil field environments. Assessing the stress and strain at the root of the defects, is essential to estimate the influence of flaws on CT fatigue life. This is physically difficult to accomplish experimentally due to the small defect size and limited access to the flaw during testing. Therefore, FEA is conducted on CT samples with and without flaws of realistic size and shape. These results are used to assess the validity of conventional notch strain analysis techniques.
Conventional notch strain analysis models have long been used to estimate localized notch root strains. This paper investigates applicability of conventional notch strain analysis under bulk plasticity situations for CT.
This paper presents a comparison of Neuber's rule and Glinka's strain energy density approaches, along with an empirical model developed to estimate notch root strain for CT applications.