bluuebunny/crossref_metadata_2025 huggingface dataset:
A Novel Approach to Reduce Breakdown Pressure of Unconventional Rocks Using Cyclic Injection Scheme
Authors: Al-Nakhli Ayman , Tariq Zeeshan , Mahmoud Mohamed , Abdulraheem Abdulazeez , Al-Shehri Dhafer , Murtaza Mobeen
Published: November 2019

Recent rise in global warming and fluctuations in world economy needs the best engineering designs to extract hydrocarbons from unconventional resources. Unconventional resources mostly found in over-pressured and deep formations, where the host rock has very high strength and integrity. Fracturing techniques becomes very challenging when implemented in these types of rocks, and in many cases approached to the maximum operational limits without generating any fracture. This leaves a small operational window to initiate and place the hydraulic fractures. Current stimulation methods to fracture these formations involve with adverse environmental effects and high costs due to the entailment of water mixed with huge volumes of chemicals such as biocides, scale inhibitors, polymers, friction reducers, rheology modifiers, corrosion inhibitors, and many more.

In this study, a novel environmentally friendly approach to reduce the breakdown pressure of the unconventional rock is presented. The new approach makes it possible to fracture the high strength rocks more economically and in more environmentally friendly way. The new method incorporates the injection of chemical free fracturing fluid in a series of cycles with a progressive increase of pressure in every cycle. This will allow stress relaxation at the fracture tip and correspondingly enough time for fracturing fluid to infiltrate deep inside the rock sample and weaken the rock matrix. As a result of which the tensile strength-ultimately the breakdown pressure of the rock gets reduced. The present study is carried out on different cement blocks.

The post treatment experimental analysis confirmed the success of cyclic fracturing treatment. The results of this study showed that the newly formulated method of cyclic injection can reduce the breakdown pressure by up to 24% of the original value. This reduction in breakdown pressure helped to overcome the operational limits in the field and makes the fracturing operation greener.
Sensitivity Analysis and Decision Trees for the Identification of the Causes of Pressure Oscillations in Oil&Gas Production Systems
Authors: Borghi Riccardo , Bianco Amalia , Rizzo Cascio Joseph , Cadei Luca , Montini Marco , Zio Enrico , Baraldi Piero , Lu Xuefei
Published: November 2019

An Oil&Gas production system is based on the pressure balance between the reservoir and the delivery point. Since a deviation of the flowing conditions in a single point of the production system has consequences in the entire asset, a big challenge for flow assurance engineers is to preserve a stable pressure in the system, with a particular attention at the separator level.

Given that the description of pressure oscillations in the systems provided by the available simulators, based on first principle, is not always enough accurate and reliable as needed for practical applications, it is fundamental to develop models and tools to help plant operators in understanding the phenomenon and properly managing it. In this context, the objective of the present work is to use large datasets, containing historical measurements of hundreds of plant signals, for identifying the most critical components of the production system with respect to the pressure oscillation phenomenon and extracting knowledge from it.

To this aim, a novel indicator of the intensity of the pressure oscillation phenomenon in the separators has been firstly defined combining Discrete Short Time Fourier Transform and Principal Component Analysis. Then, a method to extract information on the causes of the oscillation phenomenon has been developed. It is based on (i) the prioritization of the plant signals importance with respect to the pressure oscillation by using the Maximum Information Coefficient and the moment-independent Kolmogorov-Smirnov distance; (ii) the aggregation of the signal for the identification of the most critical plant components; (iii) the extraction of rules describing the phenomenon by developing a Classification And Regression Tree model whose inputs are the most important signals in (i).

This method has been verified considering a production plant operated by Eni where the oscillations in the separator's pressure are frequent. The results show the effectiveness of the developed indicator of the intensity of oscillation and provide hints about the physical causes.
Advanced Loss Circulation Spacer System in UAE Enables Successful Cementation of 9 5/8" Casing and Required Zonal Isolation during Severe Losses
Authors: El Hassan Azza , Alaleeli Ahmed Rashed , Hamidzada Ahmedagha , Jose De Barros Adelson , Al Katheeri Yousif , Bin Tarsh Fatima , Aliyeva Gunay
Published: November 2019

It is common to be faced with severe losses prior to cementing the 9 5-8 in. intermediate casing in an offshore field in UAE. Intermediate casing covers weak zones and as a results there is always a high risk of formation breakdown and induced losses while running the casing and before it reaches intended setting point. The average losses experienced during drilling the 12 1-4 in. hole may exceed 100 BPH.

The main challenge in the case reviewed in this paper was that the formation was fracturing during casing running, compromising ability to achieve proper zonal isolation and successful cement job execution.

To address the challenge a special LCM Spacer system was proposed, designed to minimize or eliminate the losses during the primary cement job by offering superior sealing capabilities. This LCM Spacer system can easily mitigate loss circulation while cementing, based on ultra-low invasion technology forming a barrier across loss zones. It creates a film across formation walls and reduces the loss circulation ranging from partial to total losses on permeable, fragile, weak formation, natural fractures and depleted reservoirs. It also improves wellbore stability and ECD’s along the wellbore and expected loss zones.

The LCM Spacer system was designed and implemented based on the well conditions, design guidelines and previously recorded global success of the system applied in similar applications.
Ground Robotics Enabler for Normally Unattended Installations
Authors: Munoz Jean-Michel , Bartoli Eric , Meyer Eric , Berson François , Mackinnon Dave , Carles Nicolas , Nourisson Guilhem , Kydd Kris , Murdoch Andrew
Published: November 2019

Normally Unattended Installations with presence of people on site only once per year (NUI-1Y) for maintenance campaigns is the ultimate aim of unmanned concepts and a new frontier for cost reduction. Ground robotics is one enabler of this goal. This new technology is in its infancy and still requires technological and organizational advancements to be readily accepted and supported by the industry.

Total fully supports the unmanned concept and has been involved for several years in the development of autonomous ground robots capable of working in potentially hazardous environments. Adopting ground robots in our operations is not only a matter of Technology Readiness Level but also requires expertise on how to use this new technology. Accordingly, the Total roadmap for robotics development focuses on three key areas:–Technology development: Starting from the ARGOS Challenge back in 2014 - Total has been engaged in the development of a new series of robots for anomaly detection / emergency response, and started a Joint Industry Project in 2019 on work class operating robots with simple and complex manipulation capabilities. The anomaly detection robot is now ready to be deployed on operational sites with the first deployment in the UK planned for September 2019.–Operating Experience: Identifying limitations and capabilities of robots is essential to integrating them into our operating concepts. Additionally, Total has set up a robotics development platform where robots are regularly tested and challenged by Field Operations personnel to find new use cases and to share this new technology within the organization.–Reliability: Unmanned design concepts using robots will not be accepted if the robots are not reliable. Therefore, to give confidence to decision makers, long term pilots are planned on several operational sites to gain the thousands of hours of operating experience needed before approving the development of new assets employing this technology.

This presentation gives an overview of the Total roadmap on robotics, sharing results of the latest developments and how robots are being integrated in our operating philosophies.
Identifying Facies Control on Diagenesis and Reservoir Quality of an Offshore Mid-jurassic Reservoir
Authors: Zakaria Hasan , Al-Hammadi Mariam , Lehmann Christoph , Al-Hassani Sultan , Ahmed Shafiq , Khan Owais , Al-Ali Ahmed
Published: November 2019

A sedimentological study of an Offshore, mid-Jurassic reservoir was carried out in order to understand reservoir quality and reservoir architecture. In-house core description, and analysis of open-hole petrophysical log interpretation and conventional core analysis, enabled the authors to interpret the depositional environment and produce hand drawn facies maps to understand the facies architecture; by developing facies scheme, depending of depositional environment comingled with diagenetic process.

About 2,285 ft of core and 1,799 thinsections were described from 18 wells, distributed throughout the field. Description of core was done at 1:50 scale and about 495 thinsections were pictured throughout the reservoir section. Detailed description of textural and faunal content, along with sedimentary features was carried out to determine the depositional model and facies architecture. By analyzing the diagenetic features and porosity type, Reservoir Quality controls were derived. All these elements were taken into consideration in order to build facies scheme that not only justifies the depositional environment but also incorporates the impact of diagenesis.

A low relief, very active shoal system on a giant carbonate platform was interpreted. Various Lithofacies were grouped into 5 Facies associations keeping in mind depositional environment and diagenetic impact. This model was used to make 4 hand drawn facies maps representing reservoir X and High permeable layer, X7 with general tendency of better facies in the northern part of the field.

The novelty of this work is the differential degree of cementation due to the abundance of echinoderms degrading the reservoir quality, and identifying these dominant echinoderm facies zones allows us better well placement by avoiding them.
A Business-Oriented Framework to Evaluate Advanced Analytics for Predictive Maintenance: Measuring Benefits-Effort Tradeoff
Authors: Cadei Luca , Corneo Andrea , Milana Diletta , Loffreno Danilo , Lancia Lorenzo , Montini Marco , Rossi Gianmarco , Purlalli Elisabetta , Fier Piero , Carducci Francesco , Nizzolo Riccardo
Published: November 2019

The use of advanced analytics techniques has become pivotal for the Digital Transformation of the Oil and Gas Industry. Most of these models are used to predict and avoid the off-spec behaviors of both equipment and functional units of the plant and also for predicting overshooting events in advance allows plant’s operators to avoid production down-time.

From a Machine Learning perspective, predicting off-specs situation and peaks in time signal is a complex task, due to the great rarity of events. For the very same reason, using standard data science measures – like Area Under the Curve (AUC), Recall and Precision – can lead to misleading performance indicators. In fact, a model that predicts no off-spec would have a high AUC just because of the unbalanced classes, leading to many false alarms. In this paper we present a business-oriented validation framework for big data analytics and machine learning models applied to a upstream production plant. This allow to evaluate both the effort required to operators and the expected benefit that could be achieved.

The validation metrics defined take the classical Data Science measures to the business domain. This allow to adapt the model to the very specific use case and end user addressing the specific upstream plants constraints. This framework allows to define the optimal tradeoff between effort required and preventable events, providing statistics and KPIs to evaluate it. Normalized Recall (NR) takes into account both the percentage of events intercepted and the effort required, in terms of Attention Time (AT), when the operator should pay attention to the equipment involved. Plant operators can now have an idea of the results they can achieve with respect to the maximum effort required. Moreover, to prove the goodness of the model, we defined the lift in the NR as the ratio of the model NR and the NR that would be obtained by randomly distributing the same number of alarms.

We applied this framework to specific use cases obtaining an expected recall of 40-50% with an expected effort of 5-10% of the time (considering more than 6 months). The effort is actually lower, since the operator is not requested to be fully committed to the alarm. The innovative framework developed is able to demonstrate the real operating capability of the analytics implemented on field, highlighting both the effort required to operators and the accuracy of machine learning tools.
Setting Up of Project Control Learning Academy in ADNOC
Authors: Balasubramanian Nagarajan , Albreiki Ali , Basioni Ahmed
Published: November 2019

The Project portfolio in the Oil & Gas industry across the value chain is quite large. Significant investments are done in complex environments to manage these Portfolio with annual budgets in International Oil Companies and National Oil Companies running into several billions of dollars. There are many challenges managing Projects and one of the key functions that helps in managing Projects is "Project Controls".

A Unified Value Assurance Process for Projects in the Upstream Business unit was rolled out in July 2015. Based on the learnings from previous project execution and challenges to manage Project schedules, cost, budgets and risks, it was felt that the knowledge level of the Project Management and Project controls function needs to be raised. It was in this context that an idea to set up a Projects Academy came about. Preliminary evaluation for this academy showed extensive efforts, coordination, involvement of external parties and extended time to get the Project Academy set-up. As a quick win, the upstream business line supported the establishment of a "Project Control Learning Academy" with in-house resources.

We will present in this paper how the Project Control Learning Academy was set-up and training being imparted through Human Capital function. We will also address the lessons learnt and the future course of action for enhancing the Academy.
Preparations for Foam Gas Shut off in Carbonate Reservoirs
Authors: Skauge Arne , Aarra Morten Gunnar , Ormehaug Per Arne , Solbakken Jonas , Mogensen Kristian , Masalmeh Shehadeh
Published: November 2019

High GOR is a constraint for many production wells. Foam has been proved able to reduce GOR in several field production well treatments. The primary goal of this study is to qualify foams for use at reservoir conditions (280 bars, 103 °C). Foam will block gas and thereby reduce Gas-Oil Ratio (GOR) and improve field oil production.

Bulk foam experiments and dynamic foam core flooding experiments have been performed to qualify foam for gas shut off at reservoir condition. Foam has been studied in static foam tests using different surfactants, and in limestone core flood experiments at reduced conditions 30 bars and 50 °C. Further foam generation and gas blocking test at reservoir conditions have been conducted both in outcrop and in reservoir material.

Dynamic core flooding experiments at 30 barg and 50 °C have shown generation of moderate to strong foams in carbonate limestone core material both with Nitrogen and Methane as the gas phase. Strong foam with mobility reduction factors around 65-70 have been generated in reservoir core material at reservoir conditions. The presence of oil in the carbonate material is a challenge for in-situ foam generation. One solution to the problem has been identified by use of a pre-flush with FS-500 (fluorinated surfactant), prior to alpha olefin sulfonate (AOS). CO2-foamers such as Duomeen has been tested, but gave no foam with Nitrogen as gas phase. Higher concentration of AOS surfactant was able to generate in-situ foam without assistance of fluorinated surfactant. The generated foam is stable also with lower surfactant concentration after first generation. The mobility reduction factor is constant for a range of surfactant concentrations.

Strong foam has been generated in carbonate reservoir core material at reservoir conditions. The presence of oil in carbonate material prevents in-situ foam generation at low surfactant concentration, but gives strong foam at higher surfactant concentration.
Rock Classification Based on Micro-CT Images using Machine Learning Techniques
Authors: Shaik Abdul Ravoof , Al-Ratrout Ahmed Ahed , AlSumaiti Ali M , Jilani Abdul Khader
Published: November 2019

Rock classification plays significant role in determining the fluid flow movement inside the reservoir. With recent developments in computer vision of porous medium and artificial intelligence techniques, it is now possible to visualize unprecedented detail at the scale of individual grains, understand the patterns of contact angles and its direct connection to multiphase fluid movements within the porous media. The outcome of this work is a probabilistic rock classification model that provides a reliable and realistic description of the reservoir.

As part of this work, 400 fully brine saturated 3D micro-CT images of Bentheimer and Clashach micro core plugs are utilized. Various three-dimension image analysis techniques are applied to quantify the rock properties (e.g. porosity, absolute permeability) and to extract pore structure information, such as pore throat distribution, pore connectivity and pore roughness from these images. The rock surface roughness is quantified as the local deviation from the plane (AlRatrout et al. 2018). The whole image dataset is divided into two separate subsets, 80% for training purpose and 20% for testing purpose. Both subsets are fed to an artificial intelligence-based model to verify and validate the results. To improve the accuracy of the model, k-fold validation technique is implemented.

The accuracy of the developed model is validated using Root-Mean-Square Error (RMSE), coefficient of determination (R2) and relative error (RE). Blind test of comparing predicted results with second subset of experimental data have shown that the developed model is capable to predict rock type with a maximum error of 3.5%. The results of this study indicate that for the given dataset, pore surface roughness has dominant effect on rock classification.

The accuracy of the developed model can be improved by incorporating additional information, for example rock mineralogy. However, the developed model is limited only aforementioned rock types, can be easily extended to other rock types provided enough micro CT images are available.
Seismic Diffraction Imaging in Laterally Varying Velocity Media for Frequency Bandwidth Expansion - Application in Carbonate Field Sarawak, Malaysia
Authors: Bashir Yasir , Abdul Latif Abdul Halim , Rezaei Shiba , Mahgoub Mohamed , Moussavi Alashloo Syed Yaser , Hermana Maman , Prasad Ghosh Deva , Weng Sum Chow
Published: November 2019

Seismic Imaging for the small-scale feature in complex subsurface geology such as Carbonate is not easy to capture because of propagated wave affected by heterogeneous properties of objects in the subsurface. The principal goal of anisotropic seismic diffraction & reflection imaging is to get a subsurface image of structural features with the greatest sharpness or resolution. In this paper, we have presented a new approach for anisotropic diffraction preservation using offset and angle domain data during the initial data processing. Which leads to the better preservation of diffractions amplitude in laterally varying velocity condition. The plane-wave destruction filter is used with a modified approximation for Diffraction separation as the conventional filtering techniques mixed the diffraction amplitudes when there are a series of diffraction hyperbola. Further, the implementation of the proposed method has proven on carbonate field data from Sarawak Basin for steeply dipping Carbonate Build-up.
Computational Fluid Dynamics of HCl Single and Two-Phase Oil Flow in a Multi-Stage Vertical and Horizontal Acid Fractured Well
Authors: Al Hajeri Talal , Rahman Md Motiur
Published: November 2019

Currently, the oil industry is using hydraulic fracture as a tool to exploit tight and ultra-tight oil formations. In carbonates, acid fracturing is common, unlike proppant fracturing in sandsones. The main objective of this paper is to study the behaviour of HCl injected and oil flow back from a horizontal well with multi-stage acid fractures (fractured hydraulically). For a vertical well, a single acid fracture is common.

The 2D fracture model and psedo-3D fracture model are incorporated in this integrated program for acid fracturing with all geomechanics and operational constraints. With five stages of fractures, post-fracture oil production from an acid fractured horizontal/vertical well is generated from this integrated model. Program is written in MATHCAD to observe the volumetric flow rate in steady-state, transient, and pseudosteady regime. ANSYS Fluent is used to carry out a computational fluid dynamics (CFD) for oil flow back along the fractures. CFD is applied to observe production rates where sequential pad fluid and acid injection is performed until the desired fracture dimensions are reached.

Results from production model shows, for steady-state, production increased from 44 to 60 STB/D and from 113 to 124 STB/D with P-3D-C and 2D-PKN-C fracture model respectively. CFD simulation is performed using a viscous model with gravitational and turbulent effects and the results show an increase in radial turbulence at the outlet of the fracture. The absolute pressure exerted on the walls is 1700 psi and the flow velocity increased from the tip at 39.4 ft/min covering a fracture length of 500 ft in both steady-state and transient flow.

This paper investigates the effect of acid fracturing on oil production using a predetermined fracture model and dimensions. The flow characteristics are challenged in multi-stage fractures in horizontal and vertical well. The outcome of CFD will assist in upscaling the simulation to a 3D model with field values from existing wells for validity. A further development with fracture simulation are carried out for vertical and horizontal fracture to understand the deformation behavior on the predetermined zone. This paper will contribute to advanced well stimulation techniques of acid fracturing that are representative of actual field applications.
A Comprehensive Analytical Approach to Evaluate Well Performance in a Giant Offshore Brownfield
Authors: Zhao Wenyang , Al-Neaimi Ahmed Khaleefa , Saif Omar Yousef , Al-Feky Mohamed Helmy , Abed Abdalla Abdel
Published: November 2019

Reservoir management is a data driven process with an objective to achieve an optimum ultimate oil recovery. It is fundamental to obtain a proper understanding of well and reservoir performance, which can only be built based on acquired data. Data acquisition in brownfield has been a significant obstacle hindering the decision making process. Comprehensive utilization of available data becomes more critical.

This paper presents an analytical approach of evaluating well performance based on an exploration of the conventional lift curve method. Lift curve is basically a correlation between oil production rate and wellhead flowing pressure, which is generated based on flow testing results. In addition to the conventional way of observing a single well's performance, the analytical approach integrates all the wells’ historical and current lift curves as well as GOR and water cut performance. The analysis is performed in two dimensions. The first one is the well historical performance evolvement. And the second one is the offset wells’ performance comparison. The data driven analytical approach has been improving the understanding of well performance and efficiency of reservoir management based on an automated analytical model. The analysis has revealed a pattern of well performance changes, which could be utilized to alert the non-preferable changes. These changes could be avoided or delayed by taking proactive actions. For instance, wells with potential gas encroachment risks have been observed before GOR performance has enough evidence to raise the alert. Actions has been proposed and taken to mitigate the reservoir issue, which has been confirmed by further flow tests. The nearby wells’ cross comparison has shown great value in both reservoir analysis and field development. Improvement of horizontal wells has been evaluated to address the necessity of horizontalization in certain areas. Well intervention candidates could be identified. The observations and findings will affect the future completion strategies. Uncertainty in flow testing results is always a governing challenge in reservoir management process. The reliability of reservoir analysis is strongly dependent on the accuracy of reservoir surveillance data. The proposed approach can also further validate the input data through cross-checking with offset wells’ performance.
Stuck Pipe Early Warning System Utilizing Moving Window Machine Learning Approach
Authors: Ahmed Omogbolahan S , Aman Beshir M , Zahrani Majed A. , Ajikobi Folorunsho I.
Published: November 2019

As stuck pipe continues to be a major contributor to non-productive time (NPT) in drilling for oil and gas operations, efforts to mitigate its incidence cannot be over emphasized. A machine learning approach is presented in this paper to identify warning signals and give early indications for an impending stuck pipe possibility during drilling activities so as to take proactive measures to mitigate its occurrence.

The model uses a moving window-based approach to capture key drilling parameters trends and apply an unsupervised machine learning algorithm to predict abnormalities in the parameters’ rate of change. It utilizes most commonly available drilling real-time data and is therefore deployable in all type of wells. No pre-drill model is essentially required as the model utilizes a self-learning and self-adjusting model.

The methodology involves the use of change point detection in identifying rig activity and the associated drilling parameters so as to capture relevant parametric trend for analysis. Inherent in the parameter trend are the different factors that affects their readings; such as wellbore geometry, bottom-hole assembly (BHA), dogleg severity (DLS), formation characteristics, pump flow rate and pipe rotations.

The algorithm has been tested on historical wells data in which stuck pipe incidence, near-miss stuck pipe occurred, and incidence-free wells to prove the concept. The results of the model performance is hereby presented along with an accuracy measure.
Scratch Test for Strength and Toughness of Oil Well Cement with Nanoclay as an Additive
Authors: Murtaza Mobeen , Rahman Mohammad Kalimur , Al Majed Abdulaziz Abdulla , Tariq Zeeshan , Mahmoud Mohamed
Published: November 2019

The mechanical properties are determined to measure the sustainability and long-lasting behavior of cement slurry under wellbore conditions. Different measurement methods were adopted in the past to study the mechanical behavior of a cement slurry. The most commonly used methods applied in oil and gas sector are cement crushing and acoustic velocities measurements. Both techniques have some limitations and additional techniques are warranted. Scratch test technique is commonly used for characterization of mechanical properties of metals, coatings and other materials. Advances in scratch testing of materials has resulted in its application to cohesive material such as rocks and cement. Recently, scratch test has been successfully applied for the strength evaluation of oil well cement. In this paper, we present the results of scratch tests carried out on oil well cement using type G cement and the specimens modified using nanoclay as an additive. The compressive strength test results from scratch test was compared to the macro level testing of cement cores loaded in compression up to failure. The dynamic elastic parameters of cement mix, elastic modulus and Poisson's ratio, were also determined using the scratch test. The scratch test based strength measurement technique will serve as a very handy tool for drilling and geomechanics engineers to study the mechanical properties of the cement slurry aged under different wellbore conditions with high level of certainty.
Iron Sulfide and Zinc Sulfide Inhibition and Scale Inhibitor Consumption
Authors: Alharbi Bader , Aljeaban Norah , Graham Alexander , Sorbie Kenneth S.
Published: November 2019

Iron sulfide (FeS) and zinc sulfide (ZnS) scales have been observed in many sour oil and gas wells. FeS often forms alongside other scales such as calcium carbonate and barium sulfate and such scales can be removed using chemicals like hydrochloric acid (HCl) and chelating agents. However, there are several drawbacks associated with the FeS removal by acid. For example, HCl acid, which outperforms other dissolvers has a high corrosion rate and generates hydrogen sulfide (H2S) gas as a byproduct. Other dissolvers, including chelating agents, often have low dissolution rates. Therefore, FeS inhibition is preferred as a strategy rather than allowing it to form followed by its removal.

The objective of this paper is to investigate the inhibition efficiency of various inhibitors for preventing FeS and ZnS deposition. Different scale inhibitor (SI) chemistries have been examined over a wide range of parameters, including temperature, salinity, pH and concentrations of Fe, Zn and sulfide. Static formation and inhibition experiments were conducted and the progress of the reaction was monitored by inductively coupled plasma (ICP) analysis and pH. In addition, the inhibitor consumption in sulfide scale solutions has also been investigated; i.e. the inhibitor concentration has been monitored during the sulfide inhibition process to determine the role and fate of the SI itself.

Polymeric scale inhibitors, including phosphino polycarboxylic acid (PPCA), showed a high inhibition efficiency for ZnS in different salinity and temperature conditions. On the other hand, some polymeric scale inhibitor that prevented the deposition of ZnS completely failed to inhibit FeS. It was found that, in mixed FeS and ZnS systems where both sulfide scales deposited, the precipitation of FeS had a negative impact on the inhibition efficiency for ZnS. By analogy, the FeS formation can affect the inhibition efficiency for other scales such as calcium carbonate and barium sulfate. In addition, in our SI consumption experiments we found that the scale inhibitor was consumed in ZnS solutions while there was no decrease (no SI consumption) in the scale inhibitor concentrations in FeS solutions.

Based on these results, we demonstrate that it is easier to inhibit ZnS rather than FeS under the same conditions. The presence of FeS had a negative impact on the performance of the scale inhibitor for ZnS and similar effects might occur in FeS/conventional scale systems. For the first time in a sulfide scaling system, this work examines if the scale inhibitor remains at its original dosage in solution or if it declines. There were two distinct behaviors, the scale inhibitor was consumed in ZnS but not in FeS solutions.
Contractor Certification Management System for Effective Project Handling
Authors: Abbas Zafar , Al Shehi Abdulla Ahmed
Published: November 2019

Engineering, procurement and construction (EPC) projects play an important role in oil and Gas & energy as well as petrochemicals & construction (civil) sectors not only for sustainable production but also to meet projected future demands. Therefore successful execution of projects is very important for industry. The paper discusse the proven sources of project delays at macro level. This paper furthers this discussion by introducing a unique mechanism of contractor certification management. This mechanism will oversee the contractor's performance and project delay's contributors. A mechanism to rate the contractors based on their performance will provide another tool to monitor contractors. Contrctactor certification management system might prove very successful mechanism that would help oranizations save their significant cost by timely excution of projects. This mechanism will provide a platform for contractors to compete with others, get high rating and receive significant appreciation.
Salt Creeping Effect on Borehole Collapse and Well Completion Design, Based on South Oman Field Experience
Authors: Moiseenkov Alexey , Smirnov Dmitrii , Mahajan Sandeep , Al Hadhrami Abdullah , Al Azizi Issa , Shabibi Hilal , Balushi Yousuf , Omairi Mahmood , Rashdi Mansoor
Published: November 2019

There have been many oil and gas field discoveries in the Cambrian Ara Group intra-salt carbonate rocks in the South Oman Salt Basin. These carbonates represent self-charging petroleum system with over-pressured hydrocarbon accumulation in dolomitized rock encased in the salt. Drilling and completion wells going through salt is challenging. Salt creeping behavior results in issues of stuck pipe during drilling operations, casings deformation and collapse that have led to well suspension and abandonment.

The full set of the available historical data analyzed to identify magnitude and history of the problem. The study conducted to estimate of salt creep magnitude, to assess the effect of the salt creep on cement quality, drilling and completion risks. The risk of salt creep on the drilling, completion and long-term well integrity was evaluated with multi-disciplinary integration of geological, geomechanical, petrophysical and well engineering aspects to minimize and mitigate the salt creeping risks. In addition to identify root cause for completion failure and providing recommendations to drilling practices, cementation and completion design that can improve well delivery process.

Salt creep behavior presents drilling challenges associated with excessive torque, stuck pipe, casing deformation, and poor cementing job. Salt creep associated risks to drilling and well integrity should be managed and mitigated. Key study findings captured for wells designs were: Salt creep rate increases with depth, salt thickness and differential stress (function of MW)Non uniform loading decreases the collapse rating of the casing and results in casing deformationNon-uniform loading likely due to poor cementing, interface between rigid carbonate intervals and salt, and irregular open hole quality.

Studied casing collapse cases could likely be attributed to several factors or combinations of factors such as salt mobility behavior, drilling with low MW, poor cement jobs and loss of internal hydrostatic support for the casing after cement job between liners lap. The improved multi-disciplinary understanding of salt creep is vital to reduce drilling and completion costs, unnecessary well abandonment and achieve good life cycle well integrity i.e. avoid extra side-track and workover cost due to integrity issues. The best practices and conclusions summarized in the study for drilling and completion design expected to benefit the exploration and development projects for the salt encased carbonate reservoirs around the globe.
Data-Driven Vs. Traditional Reservoir Numerical Models: A Case Study Comparison of Applicability, Practicality and Performance
Authors: Alatrach Yara , Saputelli Luigi , Narayanan Ram , Mohan Richard , Alklih Mohamad Yousef , Rubio Erismar
Published: November 2019

Efficient reservoir management is defined by its workflow structure stretching from a comprehensive integrated reservoir characterization (static and dynamic) to fast and reliable decision making for optimal field development planning. A lengthy and fragmented process that is scattered among multiple disciplines and data domains. The oil industry has made tremendous effort in advancing technologies to enable faster and smarter subsurface modeling, history matching, scenario prediction and risk analyses. Achieving optimality with reduced-risk requires typically prohibited high amount of human effort and technology resources.

As we enter into the Fourth Industrial Revolution of Big Data, Artificial Intelligence (AI) and Internet of Things (IOT) devices, alternatives complimentary tools to the conventional techniques have surfaced. The purpose of this work is to demonstrate the advantages and shortfalls of commercially available data-driven model techniques for dynamic reservoir forecast as compared to traditional numeric simulation techniques. In this paper, a consistent procedure to compare the performance of both data-driven models and full-physics numerical models is developed and discussed. The procedure was tested on an onshore reservoir located in Abu Dhabi, UAE that provided the basis and results for the analysis. The approach included analysis of human resources requirements, computer hardware, simulation performance and models updating strategy.
Design and Implementation Challenges for MLLD System
Authors: Kikuchi Shuichi , Fujita Kazuhiro , Nukanobu Gentaro
Published: November 2019

A water flooding pattern using maximum reservoir contact (MRC) wells will be utilized for the future developments of reservoirs in a giant brown field offshore Abu Dhabi. The increase in the reservoir contact together with the application of intelligent completion (IC) for the reservoir management is an effective way to improve the sweep efficiency, enhance oil production and minimize early water breakthrough. Meanwhile, the field is much congested with existing wells drilled from offshore well head towers and several artificial islands (AIs). In addition, many MRC horizontal wells have been and will be drilled in the overlaid reservoirs. Hence, well collision alarms are increasing day by day when planning a new well.

To meet with the field development perspectives as well as coping with such a critical field circumstance, unique well architectures with a multi-lateral IC, namely Multi-lateral Line Drive (MLLD) system are designed and the techno-economic analysis has been completed for specific cases.

This system will enable to reduce the overall drilling and completion cost for the field development with no adverse impact and mitigate the well collision risk by minimizing the number of mother wellbores penetrating through the overlaid reservoirs and provide real time monitoring and control to add values to the reservoir management.

This paper presents the drilling and completion strategy for the future reservoir developments, the MLLD system designs and associated technical challenges. In addition, outcomes from the case studies are addressed.
Improving Project Delivery Using Virtual Reality in Design Reviews —A Case Study
Authors: Ghadban Wassim , Kozina Vladan , Kelly Branwen
Published: November 2019

With the advent of the computerized 3D model environment, the engineering review process for complex process plants has improved dramatically, however, recent technological advances are facilitating the next step in productivity.

Typically, engineering companies conduct design reviews using a multidisciplinary panel of seasoned engineering experts to assess the safety and the utility of the design. The review is based upon a combination of traditional paper-based deliverables and on-screen views of the 3D model using conventional software tools, e.g. SP3D, PDMS and PDS. The Operations function is often not represented in the review phase at this early stage in the lifecycle of the asset.

By conducting two separate design review exercises, first using the conventional design review method followed by a review built around virtual reality (VR) immersion, we were able to demonstrate incremental benefits possible through the incorporation of VR technology. The identified benefits fell into two main categories, specifically identification of design deficiencies that: were not observable using traditional design review methodswere overlooked by the traditional panel of expert reviewers

Using VR technology, the immersive model review was provided in an intuitive format which allowed deeper understanding of the spatial context and allowed a more diverse team of field operatives and maintenance personnel to participate. The final design outcome was improved by the addition of practical insights from operations stakeholders who would otherwise have been excluded from the design review process.

Ultimately, the combination of improved spatial understanding and greater diversity of inputs led to a client-certified savings of USD$2.55M in future modifications and reworks.
Middle East Steamflood Field Optimization Demonstration Project
Authors: Behm Ed , Al Asimi Mohammed , Al Maskari Sara , Juna Wladimir , Klie Hector , Le Duc , Lutidze Giorgiy , Rastegar Reza , Reynolds Albert , Tathed Vinit , Younis Rami , Zhang Yuchen
Published: November 2019

Occidental Mukhaizna completed a steamflood field optimization demonstration project involving about 100 Mukhaizna wells from Mid-December 2018 to Mid-March 2019.

The field demonstration involves a data analytics process that provides recommendations on the best steam injection allocation among wells in order to improve overall steamflood performance. The process uses a low fidelity physics-based proxy model and cloud-based parallel processing. A field optimization engineer history matches and anchors a proxy model to current well and field operating constraints. The engineer completes hundreds of forward runs as part of an optimization algorithm to identify scenarios most likely to help increase value (oil production per steam injected) over the short term in the field, while honoring all producing and injection well operating ranges. The reservoir management team vets the rate change ideas generated and provides their recommendations for changes so the likely best and most practical overall scenario is implemented. The process is refreshed monthly so field performance results are included immediately, and the optimization process is kept evergreen. The field results so far have been encouraging, yielding an increase in oil production that has exceeded expectations.

This paper will describe the data analytics field optimization process and workflow, present the baseline performance versus field demonstration results, and share lessons learned.
Challenges in Design of Wellfluid H2S Mitigation on an Offshore Wellhead Platform - A Case Study
Authors: Subramanian Senthilkumar , Singh Harendra , Kamal Faris Ragheb , Takieddine Oussama
Published: November 2019

Hydrogen Sulfide (H2S) occurs naturally in well fluid and imposes variety of challenges in oil and gas industry. Although there are many methods that may be employed to remove H2S from gas and liquid streams, selection of technology, design, installation & operation on a remote unmanned wellhead platform offers unique challenges. This paper presents NPCC’s experiences in implementation of H2S mitigation unit on a recent offshore well head platform project.

Offshore wellhead platforms are designed to minimize manning frequency and duration of stay. Further, climatic conditions - heavy rains during monsoon impose additional challenges to logistics, restricting movement of crew members, service boat requirements to replenish consumables on unmanned wellhead platform. Therefore, it’s preferred to select wellfluid H2S mitigation unit requiring minimal operational intervention. Sweetening of multi-phase wellfluids (mixture of oil, gas & produced water) can be performed by direct injection of scavenger chemicals but pose problems in downstream facilities. Alternately, it was proposed to separate the wellfluid into gas & liquid streams and treat them independently for H2S removal.

Experience demonstrates that proper selection and application of proven technology are critical for wellfluid H2S mitigation. Based on assessment of various technologies, the most optimized approach for this case is use of a solid based scavenger media packed in an Adsorber vessel to treat the associated gases and a triazine based liquid scavenger to treat the separated liquids. Adsorber vessel needs to be designed considering replacement of spent media with fresh solid scavenger based on worst possible monsoon period in the region. The important design challenges include unloading of spent media and loading of fresh media into the Adsorber vessel. This involves establishing logistics in transporting fresh media to offshore and sending spent media to onshore for safe disposal. Safe land disposal practices are recommended to meet the local environmental regulations.

H2S removal provides distinct advantages and focus is now shifting towards removal at wellheads due to potential high returns on investment in current oil market. Adding new sour wells to existing production may pose limitations in downstream facilities such as existing pipeline and process complex. It is worth to consider sweetening of wellfluid at wellhead platform thus mitigating H2S at the source itself instead of augmenting existing sweetening system at downstream facility.

This paper discusses a case study based on an actual project, highlighting the design challenges and experience gained during execution of wellfluid sweetening system on a remote wellhead platform, thus providing economic benefit to all stakeholders.