bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Comparative Analysis of the Prediction of Gas Condensate Dew Point Pressure Using Advanced Machine Learning Algorithms
Authors: Lertliangchai Thitaree , Dindoruk Birol , Lu Ligang , Yang Xi 
Published: September 2021

Abstract
Dew point pressure (DPP) is a key variable that may be needed to predict the condensate to gas ratio behavior of a reservoir along with some production/completion related issues and calibrate/constrain the EOS models for integrated modeling. However, DPP is a challenging property in terms of its predictability. Recognizing the complexities, we present a state-of-the-art method for DPP prediction using advanced machine learning (ML) techniques. We compare the outcomes of our methodology with that of published empirical correlation-based approaches on two datasets with small sizes and different inputs. Our ML method noticeably outperforms the correlation-based predictors while also showing its flexibility and robustness even with small training datasets provided various classes of fluids are represented within the datasets. We have collected the condensate PVT data from public domain resources and GeoMark RFDBASE containing dew point pressure (the target variable), and the compositional data (mole percentage of each component), temperature, molecular weight (MW), MW and specific gravity (SG) of heptane plus as input variables. Using domain knowledge, before embarking the study, we have extensively checked the measurement quality and the outcomes using statistical techniques. We then apply advanced ML techniques to train predictive models with cross-validation to avoid overfitting the models to the small datasets. We compare our models against the best published DDP predictors with empirical correlation-based techniques. For fair comparisons, the correlation-based predictors are also trained using the underlying datasets. In order to improve the outcomes and using the generalized input data, pseudo-critical properties and artificial proxy features are also employed.
Clustering, Connectivity and Flow in Naturally Fractured Reservoir Analogs
Authors: Sahu Ajay K. , Roy Ankur 
Published: September 2021

Abstract
A previous study by the authors on synthetic fractal-fracture networks showed that lacunarity, a parameter that quantifies scale-dependent clustering in patterns, can be used as a proxy for connectivity and also, is an indicator of fluid flow in such model networks. In this research, we apply the concepts thus developed to the study of fractured reservoir analogs and seek solutions to more practical problems faced by modelers in the oil and gas industry. A set of seven nested fracture networks from the Devonian Sandstone of Hornelen Basin, Norway that have the same fractal-dimension but are mapped at different scales and resolutions is considered. We compare these seven natural fracture maps in terms of their lacunarity and connectivity values to test whether the former is a reasonable indicator of the latter. Additionally, these maps are also flow simulated by implementing a fracture continuum model and using a streamline simulator, TRACE3D. The values of lacunarity, connectivity and fluid recovery thus obtained are pairwise correlated with one another to look for possible relationships. The results indicate that while fracture maps that have the same fractal dimension show almost similar connectivity values, there exist subtle differences such that both the connectivity and clustering values change systematically with the scale at which the fracture networks are mapped. It is further noted that there appears to be a very good correlation between clustering, connectivity, and fluid recovery values for these fracture networks that belong to the same fractal system. The overall results indicate that while the fractal dimension is an important parameter for characterizing a specific type of fracture network geometry, it is the lacunarity or scale-dependent clustering attribute that controls connectivity in fracture maps and hence the flow properties. This research may prove helpful in quickly evaluating connectivity of fracture networks based on the lacunarity parameter. This parameter can therefore, be used for calibrating Discrete Fracture Network (DFN) models with respect to connectivity of reservoir analogs and can possibly replace the fractal dimension which is more commonly used in software that model DFNs. Additionally, while lacunarity has been mostly used for understanding network geometry in terms of clustering, we, for the first time, show how this may be directly used for understanding the potential flow behavior of fracture networks.
A Novel Method of Constructing Spatial Well Pattern for Water Flooding in Fractured-Vuggy Carbonate Reservoirs FVCRs
Authors: Wang Jing , Zhang Tuozheng , Liu Huiqing , Dong Xiaohu , Li Xiaobo , Yang Min , Liu Hongguang , Hu Gaixing , Sepehrnoori Kamy 
Published: September 2021

Abstract
Fractured-vuggy reservoir is significantly different from porous reservoirs. Ordovician reservoir in T Oilfield in China is the largest FVCR around the world. Water flooding has been applied as a prospective method in more than 140 units, but water channeling is especially serious and the recovery is only about 15%. In such reservoir, cavities and fractures are the main storage spaces and flow channels, respectively. Because the fractures and cavities are spatially non-stratified and discretized, the waterflood pattern differs significantly from that in sandstone or porous carbonate reservoirs. It is very essential to construct a spatial well pattern to match the distribution and connectivity of fractures and cavities, which is a very popular topic in recent years.
In this work, we presented a multistage construction method of spatial well pattern combining reservoir engineering with numerical simulation methods. Firstly, the economic concepts of Lorenz curve and Gini coefficient were introduced to choose the injector from all wells to achieve equilibrium displacement of injected water in the plane. Secondly, displacement and drainage equilibrium index (DDEI) was presented to determine the vertical location of the injector to achieve equilibrium displacement and drainage in vertical direction. Thirdly, the vertical locations of the producers were determined based on the distribution of reserves in vertical direction. Fourthly, the local producers were further optimized based on the cavities along the wellbore by numerical simulation. Finally, this method was successfully used to construct the spatial well patterns of fractured-vuggy units with different karst features in A unit of T Oilfield.
The results show that the oil recovery factor is inversely proportional to the Gini coefficient calculated with the combined variable of flow resistance and crude reserve rather than that calculated with flow resistance in pore reservoirs. The ratio of the reserve to formation factor, V/(kh), can be used to determine the vertical location of the injector. And the optimal DDEI which is the ratio of V/(kh) in upper reservoir of the wellbore to that in lower reservoir of the wellbore is equal to 1. The vertical locations of producers are related to the vertical distributions of reserve and cavities in different karst units. At last, the principles of constructing spatial well pattern in fractured-vuggy carbonate reservoirs were proposed.
This work provides an innovative and effective method to establish a spatial well pattern for FVCRs, which will break new ground for efficient development of FVCRs by water flooding.
A Novel Method to Detect Cement through Direct Measurement – Case Histories
Authors: Palisch Terry , Zhang Jeremy 
Published: September 2021

Abstract
Cement quality is typically determined through the use of sonic logging tools, more commonly known as cement bond logs (CBLs), or more recently ultrasonic imaging tools (USITs). In general, these tools have served the industry well over time, but with the advent of new and exotic cement blends, as well as multistage cement jobs in today's unconventional horizontal wells, the quality and even location of the cement has become more problematic for basic CBL/USIT tools to detect. In addition, these tools are ineffective through multiple uncemented casing strings.
A novel method to detect cement was developed as an offshoot of a technology used for detecting proppant in hydraulically fractured wells. This technique uses a non-radioactive tracer which exhibits a high thermal neutron capture cross section that is then incorporated into the proppant grains during manufacture. The proppant can then be detected using standard neutron-logging tools, at any time during the well's life. By incorporating small volumes of this detectible proppant into the cement slurry, the cement can then be detected using the same logging tools. This leads to identification of the top of cement, as well as the cement quality. If desired, the taggant can be staged such that the top and bottom of a cement stage can be detected.
This paper will first review the industry concerns with cement detection. It will then discuss the principles and theory behind how the taggant works, both for basic proppant detection, as well as the novel application as a vehicle for cement detection. This will also include lab testing showing no impact of the tagged proppant on cement performance. The authors will conclude by presenting several case histories of cement detection, including two horizontal well applications, one each in the Permian and Canada. A third case history will also be presented in which the cement was detected through multiple strings of uncemented casing, to verify success of a cement squeeze in a surface casing remediation.
This new technique allows for cement detection in wells in which conventional CBL/USITs are difficult to interpret, including detection of exotic cement blends, and through multiple strings of casing. This allows for more confidence in cement isolation, particularly in today's unconventional wells, where isolation of uphole formations is critical. This paper will be useful for drilling and completion engineers who are concerned with their ability to confirm cement quality, as well as production engineers who must perform remedial cementing operations.
Transport of Polymers in Low Permeability Carbonate Rocks
Authors: Song Haofeng , Ghosh Pinaki , Mohanty Kishore 
Published: September 2021

Abstract
Polymer transport and retention affect oil recovery and economic feasibility of EOR processes. Most studies on polymer transport have focused on sandstones with permeabilities (k) higher than 200 mD. A limited number of studies were conducted in carbonates with k less than 100 mD and very few in the presence of residual oil. In this work, transport of four polymers with different molecular weights (MW) and functional groups are studied in Edwards Yellow outcrop cores (k&lt;50 mD) with and without residual oil saturation (Sor). The retention of polymers was estimated by both the material balance method and the double-bank method. The polymer concentration was measured by both the total organic carbon (TOC) analyzer and the capillary tube rheology. Partially hydrolyzed acrylamide (HPAM) polymers exhibited high retention (&gt; 150 μg/g), inaccessible pore volume (IPV) greater than 7%, and high residual resistance factor (&gt;9). A sulfonated polyacrylamide (AN132), showed low retentions (&lt; 20 μg/g) and low IPV. The residual resistance factor (RRF) of AN132 in the water-saturated rock was less than 2, indicating little blocking of pore throats in these tight rocks. The retention and RRF of the AN132 polymer increased in the presence of residual oil saturation due to partial blocking of the smaller pore throats available for polymer propagation in an oil-wet core.
Connection Recipes: Exploring Optimum Connection Practices through a Data-Driven Approach
Authors: Ashari Rahmat , Sorensen Owen , Ashok Pradeepkumar , van Oort Eric , Isbell Matthew , Chovanetz Koda , Foster Nicole 
Published: September 2021

Abstract
Although numerous studies have investigated how shocks and vibrations contribute to bottomhole assembly (BHA) failures during hole-making, very few have explicitly focused on shock and vibrational behaviors during drillpipe connections. This study adopts a data-driven approach to explore various connection practices and their associated shocks and vibrations, aiming to propose optimum "connection recipes" that minimize negative drillstring impacts during connections.
This study utilized data from surface sensors as well as downhole accelerometers and gyroscopes installed both at a downhole sub and the bit. In total, 520 connections from 5 lateral sections were studied. Several quality checks and corrections were performed to ensure synchronization between surface and downhole data. The analyses focused on two connection phases specifically: going off-bottom and going back to bottom. The presence of stick-slip events and high magnitudes of both maximum and root mean squared (RMS) radial accelerations were examined together with the associated surface drilling parameters. Various visualization approaches were performed to help demonstrate the vibration and shock behaviors resulting from different going off-bottom and going back to bottom practices.
The analyses showed that restarting surface rotational speed at low values (≤ 40 RPM) risks inducing stick-slip events when going back to bottom. When the surface RPM was increased sufficiently, a notable reduction in RMS radial acceleration was observed. Maximum radial acceleration magnitude was highest before WOB application, which could be mitigated by immediate WOB re-application. Appreciable variation in the maximum radial acceleration was apparent when restarting at low (≤ 15 klbf) WOB values. When going off-bottom, drilling off should be accompanied by a reduction in the surface rotational speed to avoid a jump in the maximum radial acceleration values.
This work provides suggestions on how to execute better connections. Since the impacts of shocks and vibrations during connections have previously been largely overlooked, this study fills a knowledge gap to help establish better practices and automation routines to improve the lifespan of the bit and downhole tools.
Trends in the Relationship Between Business and Society: Understanding the Past and Preparing for the Future
Authors: Luca Christiaan , Vencken Marjolijn , van Cranenburgh Katinka , Borbor Juan Diego , Tchilinguirian Anthony 
Published: September 2021

Abstract
How can a business develop sustainable societal relationships in a world that is often described as volatile, uncertain, complex and ambiguous? While public expectations of companies are complicated and continuously changing, there are clear underlying trends in modern society that shape this relationship. Understanding these trends allows a company to develop the capability of proactively managing societal relationships. The findings of the study are especially relevant for industries that visibly operate in the public space and should anticipate societal resistance.
This paper first describes the societal trends that shaped the way people and organizations have interacted since the Second World War. In this period increasing environmental and social awareness and assertiveness developed along three evolutionary paths: –active public discourse that continuously pushes the boundaries of what is deemed acceptable and desirable, with increasing focus on human values and space for the individual;–industry sectors and international organizations that try to preempt new societal expectations with voluntary guidelines and self-regulation; and–governments that formalize important and matured parts of the public discourse and voluntary guidelines in laws and regulations.
Secondly, the authors adopt a practical model to describe how companies have struggled to keep up with this continuously evolving and dynamic societal landscape due to lack of adaptation. An increasingly defensive and reactive business approach to societal pressure has led to a low point in trust from stakeholders. To regain trust and their social license to operate companies need to take a more proactive approach to societal relationships, which require both organizational and cultural change.
Finally, the authors take the example from the safety journey, where the oil and gas industry has been very successful in demonstrating that excellence in safety is both a moral obligation and good for the bottom line. The same applies to excellence in societal relationships. Using the evolutionary model of safety culture with its maturity ladder as analogue, the authors provide a practical and value-driven framework to guide companies on their organizational and cultural change journey towards effective societal relationship management.
Industry First Openhole Alternate Path Gravel Pack Completion in HPHT Environment: Fluid Development and Case History
Authors: Pillai Pradeep , Lin Chih-Cheng , Brege Jonathan , Mohan Raj , Derkach Edward , Lafitte Valerie , Gadiyar Bala , Aung Tint Htoo , Santamaria Juan-Carlos 
Published: September 2021

Abstract
For offshore wells requiring sand control, Open Hole Gravel Packing (OHGP) with or without shunted screen technology is a common completion technique. Prior to this paper, there has been no application of shunted screen OHGP in High-Pressure High-Temperature (HPHT) environment due to lack of a viscous fluid availability in high-density divalent brines (&gt; 14.6 lbm/U.S. gal).
For the case study, the fluid requirements in terms of density and temperature were 15.4 lbm/U.S. gal and 265°F, respectively. The only brine option at this density was a blend of calcium chloride/bromide and zinc bromide. In this brine and density, none of the existing fluids work hence a novel polymer-based fluid had to be developed. The fluid had to pass the following tests a) rheology before and after subjecting to high shear of both uncontaminated and contaminated fluids at 3 different temperatures b) sand settling tests at 4 different temperatures c) Production Screen Tester to ensure the fluid does not plug the screens during the job. System Integration Tests (SIT) were performed to ensure the mixing equipment would be able to batch mix the fluid and actual pumping equipment would function properly with the fluid. The field trial planning included simulations, pre-job meetings, and fluid management plan. The job was executed as per the procedure outlined during pre-job meetings.
This paper discusses laboratory development, yard test qualification, and successful shunted screen OHGP case history of a novel 15.4 lbm/U.S. gal viscous gravel pack carrier fluid.
An Efficient Deep Learning-Based Workflow Incorporating a Reduced Physics Model for Subsurface Imaging in Unconventional Reservoirs
Authors: Onishi Tsubasa , Chen Hongquan , Datta-Gupta Akhil , Mishra Srikanta 
Published: September 2021

Abstract
We present a novel deep learning-based workflow incorporating a reduced physics model that can efficiently visualize well drainage volume and pressure front propagation in unconventional reservoirs in near real-time. The visualizations can be readily used for qualitative and quantitative characterization and forecasting of unconventional reservoirs.
Our aim is to develop an efficient workflow that allows us to ‘see’ within the subsurface given measured data, such as production data. The most simplistic way to achieve the goal will be to merely train a deep learning-based regression model where the input consists of some measured data, and the output is a subsurface image, such as pressure field. However, the high output dimension that corresponds to spatio-temporal steps makes the training inefficient. To address this challenge, an autoencoder network is applied to discover lower dimensional latent variables that represent high dimensional output images. In our approach, the regression model is trained to predict latent variables, instead of directly constructing an image. In the prediction step, the trained regression model first predicts latent variables given measured data, then the latent variables will be used as inputs of the trained decoder to generate a subsurface image. In addition, fast marching-method (FMM)-based rapid simulation workflow which transforms original 2D or 3D problems into 1D problems is used in place of full-physics simulation to efficiently generate datasets for training. The capability of the FMM-based rapid simulation allows us to generate sufficient datasets within realistic simulation times, even for field scale applications.
We first demonstrate the proposed approach using a simple illustrative example. Next, the approach is applied to a field scale reservoir model built after the publicly available data on the Hydraulic Fracturing Test Site-I (HFTS-I), which is sufficiently complex to demonstrate the power and efficacy of the approach. We will further demonstrate the utility of the approach to account for subsurface uncertainty. Our approach, for the first time, allows data-driven visualization of unconventional well drainage volume in 3D. The novelty of our approach is the framework which combines the strengths of deep learning-based models and the FMM-based rapid simulation. The workflow has flexibility to incorporate various spatial and temporal data types.
Field Pilot Test of Micro-Dispersed Gel Foam in Fractured-Vuggy Carbonate Reservoirs
Authors: Wen Yuchen , Hou Jirui , Qu Ming , Wu Weipeng , Liang Tuo , Zhang Wei , Wu Wenming 
Published: September 2021

Abstract
This paper summarizes the change rule of production performance and the EOR efficiency from the micro-dispersed gel foam injection in the fractured-vuggy carbonate reservoir of Tahe Oilfield. The TK722CH2 well group injected gas from August 2014 to September 2018. During the gas injection stage, the effect of periodic gas injection decreased obviously, the effective direction of gas injection was single and the risk of gas channeling increased greatly. The field pilot test f micro-dispersed gel foam was carried out on September 20, 2018. The fluid is injected into well group in three slugs: micro-dispersed gel foam, normal foam and nitrogen gas. As a part of the foam pilot test monitoring, a gas tracer study was performed before and after the injection of gel foam in the reservoir. After the pilot test was carried out in the TK722CH2 well group, the subsequent injection gas swept new fractures and vugs, and a new dynamic connectivity has been established. The connectivity of well group changed from 1 injection well connects with 1 production well to 1 injection well connects with 4 production wells. Through the field pilot test of micro-dispersed gel foam, this paper verifies the effect of improve gas flooding and increase sweep volume of micro-dispersed gel foam. By analyzing the results of the field pilot test, the relevant technical mechanism of micro-dispersed gel foam in fractured-vuggy reservoir is revealed. As a result, the field pilot test in this paper provides theoretical basis and technical support for the efficient development of fractured-vuggy carbonate reservoir.