bluuebunny/crossref_metadata_2025 huggingface dataset:
The First Successful Chemical EOR Pilot in the UAE: One Spot Pilot in High Temperature, High Salinity Carbonate Reservoir
Authors: Al-Amrie Omar , Peltier Sophie , Pearce Adrian , Abu-Dhabi Total , Al-Yafei Arafat , Morel Danielle , Bourrel Maurice , Bursaux Romain , Cordelier Philippe , Jouenne Stephane , Juilla Hugo , Klimenko Alexandra , Levitt David , Nguyen Michel
Published: November 2015

In 2014, Total performed a surfactant-polymer single-well pilot to test the effectiveness of a surfactant formulation developed in-house, and including a new proprietary class of surfactants with improved temperature- and salinity-tolerance characteristics. This paper unveils the results of this pilot which targeted a high temperature, high salinity carbonate reservoir. The operations were performed on an oil bearing reservoir of Lower Cretaceous age, in an offshore field operated by Total since 1974 and located 180 km offshore Abu Dhabi. Dedicated topsides were designed and installed for this EOR project. Extensive in-house laboratory studies were performed to select and synthesize the chemicals. Specific simulations, using laboratory results as input, were carried out to predict the pilot performance, design the Single Well Tracer Tests (SWTTs), and size the equipment.

In this paper we will discuss the workflow used to select the most appropriate well and present the methods and results used to characterize the reservoir. Then we will relate it to the surfactant-polymer injection field operations. Finally the reservoir monitoring activities that were necessary to preserve reservoir integrity and demonstrate the pilot efficiency will be described.

The strong decrease in remaining oil saturation measured after the chemical EOR pilot clearly proves the effectiveness of the chemicals synthesized by Total to mobilize the remaining immobile oil after water-flood.

These positive outcomes change the perception of CEOR in hot, saline Middle-East carbonate reservoirs, and could be a "game changer".
Venturi Tube Blower Applications in Reducing H2S Gas Concentration at Depurator Flotation Unit
Authors: Ekky Rizkiyadi Muhammad , Agus Setiawan Muchamad
Published: November 2015

Objective of this paper is to highlight the problem of high concentration Hydrogen Sulfide (H2S) in depurator flotation unit system at Oily Water Treatment Plant (OWTP) Pertamina Hulu Energi Offshore North West Java (ONWJ), Central Plant Processing Facilty and identification impact quality of dry crude to storage. The methodology to reduce accumulation Hydrogen Sulfide in depurator unit is using venturi tube blower system. An innovation to install venturi tube blower has been tested based on degradation of concentration and dry crude quality in Floating Storage Offloading (FSO) Arco Ardjuna prior to export. The result of application venturi tube blower showed that accumulation of Hydrogen Sulfide gasses down to the lowest point and was found very effective. Conclusion from this paper are application of venturi tube blower has proven to capture and remove the concentration Hydrogen Sulfide up to 80% and in economical aspect the requirement cost for modification are very minimum.
Design and Implementation of Well Integrity Passport
Authors: Chishti Khalid , El-Refai Mohamed , El Din Abouel Seoud , Mohamed Ashraf Khalil , Ali Mohamed Saleh , Abdulla Hussein Saad
Published: November 2015

A need was felt in ADMA OPCO for a Well Integrity monitoring and management tool which would, in a single document, capture and present the entire Well Integrity status of the well and make it available for the senior management on a click of a button; short and long term actions are well defined and clearly assigned. A similar document had been proposed and implemented for other company assets such as pipelines and pressure vessels.

Since 2003, ADMA OPCO had a legacy Well Risk Ranking System based on the ADNOC 5×5 risk matrix, which classified wells into high, medium and low risk categories. The system captured data such as Xmas Tree/Wellhead valve status, Wellhead cavity status, DHSV status, annulus pressures and any down-hole issues such as corrosion or communication. The Well Integrity Passport enhanced the risk ranking concept by taking into account the business and HSE aspect of a well. Wells with higher production or injection potential are ranked accordingly higher on the vertical axis. Similarly gas wells are ranked higher than oil or water injector wells due to their potential HSE impact in the event of a failure. The horizontal axis is the probability or the technical axis which takes into account the technical and barrier status of the well in terms of the health of various components. The passport also contains a well barrier sketch defining the well barrier envelopes (primary and secondary barriers) and their status. The passport is made available to the senior management using a web based interface called the IDBMS. The overall integrity status of wells or the status of any individual well can be seen at any time upon the click of a button.

Based on the new system, all the wells in the two main offshore fields of ADMA OPCO were reassessed. The results were similar but not exactly as from the previous risk ranking system.

The system has added great value because it is designed to produce a semi-quantitative risk score which can be a tool in prioritizing the required repairs or monitoring activities.
Flare Purge Gas Reduction Offshore Exercise
Authors: Al Hajri Abdulla , Basheer Mohsin
Published: November 2015

As part of the continuous effort to reduce/minimize flaring, an optimization project was undertaken to reduce flaring during the normal operation phase by minimizing the purge gas flow rates to the minimum acceptable limit.

The previous purge gas flow overseen by the EPC Contractor was revised using the latest API standards (API 521). As a result, the study identified a major opportunity to optimize the off-shore flaring as summarized in table-1 below:

Table 1 minimum purge gas requirements to offshore HP flares Minimum Purge Gas (Kg/hr) Actual design Revised Criteria from API (521) Revised design EPC Flare vendor Air Ingress criteria for header Air Ingress criteria for stack Back burning criteria Flare vendor + Process margin Plat-1 HP flare 787 72 48 17 54 79 Plat-2 HP flare 787 72 48 17 54 79

Revised criteria from latest API standards applied to the offshore HP flare showed that the minimum purge gas requirement should be lower than flare vendor recommendation (from the vendor datasheet).

A process margin is added to the recommended purge gas flowrate to cover for fuel gas composition and flow meter accuracy.

The new minimum purge gas requirement defined as a revised design was confirmed by company's technical team. The flare vendor also confirmed that the revised design was above the recommended minimum purge rates for the HP flare tip and committed to reduce air ingress and oxygen levels inside the flare tip and stack to acceptable points during normal purge scenarios. This would also ensure safety, reliability, and integrity.

Implementation of the purge gas reduction in the offshore HP flares was achieved by carrying out a step-by step reduction of the purge gas flow down to the flame visibility. A detailed Method of Statement was prepared to ensure a smooth purge gas reduction activity.

As the purge gas flow was reduced, the HP flare tip inspection frequency increased. At the initial stage, flare tip inspection frequency of 2 years was suggested in line with the platform shutdown schedule.
Flexural Shear Associated with Transpressional Folding of Abu Dhabi Onshore Fields
Authors: Noufal Abdelwahab , Agrab Abdelfatah El , Satti Sara , Chitrao Amogh
Published: November 2015

The Abu Dhabi onshore Anticlinal Fields are trending NE-SW and N-S, with their eastern flanks being of steeper dip (~3 ° -5°) than their western flanks (~1° -2°). In previous research, kinematics, and mechanics of onshore Abu Dhabi folded anticlines had not been addressed. The main objective of this paper is to understand the kinematics and mechanics of the folding systems.

A new approach to understanding the mechanical evolution of these anticlines is presented here through the use of conceptual modelling and theoretical approaches. A combination of geological and geophysical tools is used for determining the direction of the shear stresses along the flexural slip planes. Although textural evidence, such as karstification and diagenesis, suggests local material redistribution on different scales, compositional trends support negligible volume flux at the scale of the anticlines. The preservation of bed length and bed thickness in most of the onshore Abu Dhabi Anticlines requires the development of bed-parallel shear. Abu Dhabi Anticlinal fields are mechanically evolved by flexural shear and flexural slip folding, which is characterized by differential simple shear along the bedding planes, where deformation is concurrent with the diagenesis. The layered horizons of these folds are mostly of carbonates, where the competency contrast is low and the friction between the layers is high leading to flexural shear. In the locations, where incompetent shale layers alternate with the carbonates, flexural slip is considered - although this is very limited within Abu Dhabi anticlinal structures. In these folds, the bedding planes of less competent layers act as boundaries of shear zones. Therefore, most of the internal deformation occurs within the less competent layers by partial recrystallization and development of fractures. However, the competent layers undergo pressure solution, development of sigmoidal extensional fissures, and stylolites in most cases. Thus, the overall folding system is heterogeneous and the competent layers simply slide over one another. The dominant direction of the over-riding shear is directed toward the fold axial surface and the stresses are released along the bedding plane discontinuities. The bedding plane discontinuities are considered to represent the finite neutral surface of the fold. Folds having parallel geometrical forms have opposite directions of structural shear in transtensional and transpressional regime.

In the Abu Dhabi flexural slip shear folds, deformation in the hinge zone is characterized by pure shear, and deformation on fold limbs is characterized by components of both simple and pure shear. Strain models of pure bending, layer-parallel shear, and shear parallel to the hinge plane are shown to be the main mechanism of these folds. Preservation of these will play an important role in revealing a new play concept for the Abu Dhabi fields.
Diagnosis and Analysis of Well Abnormal Flowing Data in Dina HPHT Gas Field, West China
Authors: Liu Xiaohua , Zou Chunmei , Liu Hualin
Published: November 2015

This paper presents an integrated approach for diagnosis and synthesis of production data for gas wells in Dina HPHT reservoir, where most of the production wells exhibit everlasting abnormal flow with limited analyzable data

For production data diagnostics, we prove that for gas wells at high pressure stage (both reservoir pressure and wellbore flowing pressure are above 50MPa), the qg/(Ppi - Ppwf) versus tca plot for gas system can be substituted rigorously by qg/(Pi - Pwf) versus Gp/qg plot (similar form as liquid system) in Palacio-Blasingame decline type curve analysis; and for gas Flowing Material Balance (FMB) analysis, the qg/(Ppi - Ppwf) versus (qgtca)/[(Ppi - Ppwf)Cti] plot can be substituted by qg/(Pi - Pwf) versus Gg/(Pi - Pwf) plot. These reduced functions are used to generate simplified Blasingame diagnostic plot and FMB diagnostic plot for high pressure gas system. These simplified diagnostic plots, with no iterations or integrations when calculating, provide a quick and straightforward solution for instant detection of abnormal flowing data in field.

In well production profile synthesis, the dependence of well OGIP on individual-well-flow-rate/reservoir-flow-rate ratio is given based on "pseudo-steady-state" flow theory in a multiwell reservoir. Interference effects are coupled into the analytical model by assigning varied OGIP in production profile synthesis, which reduce the risk of erroneous results in modeling long-term production profile for wells with limited analyzable history data and make the "generated" well behavior consistent with the multi-well-reservoir behavior.
Enhancing Petrophysical Property Prediction from Well Logs Using Digital Rock Physics Technique - Case Study of a North Sea Sandstone Reservoir
Authors: Wu Jianghui , Jin Guodong , Bradley Tom , Sy Rex , Mezzatesta Alberto , Guzman Angelia
Published: November 2015

This paper presents a field case study, which integrates Digital Rock Physics (DRP) techniques and downhole logging measurements, to enhance the prediction of formation absolute permeability and drainage capillary pressure from well log data. The approach first generates numerically a digital rock model representing the formation at each given depth of interest, and then uses the model as input to simulate fluid flow and capillary-dominated fluid displacement for the determination of capillary-pressure curve and absolute permeability. Rock models are constrained by formation parameters derived from logging data, and created by simulating the way the clastic rock formed over millions of years, with periods of grain sedimentation, compaction and diagenesis. All input parameters for the rock modeling including the density, porosity, grain mineralogy, grain-size distribution (GSD), cement and clay content, are obtained directly or indirectly from downhole logging measurements.

The method's feasibility and applicability are demonstrated by applying the DRP modeling technique to one set of field data from a North Sea well contained a complete suite of logs. Cores are extensively taken from the well-consolidated sandstone formations. Laboratory measurements provide the measured permeability and capillary pressure for comparison. At various depths, the predicted permeability of rock models is in good agreement with the measured values of core sampes from the same depth, and mostly falls within the same order of magnitude as the measurements. Compared to Nuclear Magnetic Resonance (NMR)-based Coates model, the DRP-based approach gives a better predicted permeability when both methods use default values in their parameters. In addition, three depths representing different sandstone zones are randomly selected to investigate the effect of surface relaxivity on the predicted GSD, permeability and capillary pressure of rock models. When the surface relaxivity of 3 μm/s is used in this study, the DRP permeability at these depths matches very well with core measurements as well as the mobility calculated from formation tester measurements. Also, their entry capillary pressures are consistent with those from core measurements. However, the simulated pressure curves differ in shape from the measured ones, which may be attributed to limited variation of grain sizes used in the rock modeling. The promising results stemming from this study confirm the feasibility of combining the DRP technique with downhole logging measurements to accurately and reliably predict formation petrophysical properties in a timely and cost-effective manner.
General Parallel Reservoir Simulation
Authors: Beckner B. L. , Haugen K. B. , Maliassov S. , Dyadechko V. , Wiegand K. D.
Published: November 2015

Faster reservoir simulation turnaround time continues to be a major industry priority. Simultaneously, model sizes are reaching a billion cells and the recovery mechanisms and reservoir management processes to be modeled are rapidly changing and are becoming computationally more expensive. A new reservoir modeling solution has been developed to quickly solve these largest and most complex modeling studies within ExxonMobil.

This latest generation reservoir simulator has been designed from the ground up with 60 years of internal reservoir simulator development experience. Some of the key learnings incorporated into the new reservoir simulator include a requirement for a flexible and modular software framework, a general flow formulation that is decoupled from a very fast and highly accurate phase behavior engine, and unstructured architecture for unstructured grids. This simulator is optimized for massive distributed memory parallelism to take advantage of ExxonMobil's world class supercomputer, Discovery.

A new fluid agnostic formulation has been developed based on general material balance. A highly optimized and highly accurate fluid library supports liquid-liquid-vapor calculations and is the only differentiation between black-oil and compositional options. These considerations are critical for maintaining computationally efficient software under heavy software development with a large development team.

The distributed memory parallelism has been tested and has shown to be very efficient on the Discovery platform. Strong scalability tests have been run to 16,000 cores with good parallel performance to 6000 unknowns per core. These are some of the largest core counts for parallel reservoir simulation with unstructured grids seen in the industry and reduce model run times from days to minutes. These drastically reduced run times have allowed the new simulator to include heavy computational methods, such a nonlinear finite volumes or implicit reactions, for practical use as well as supporting very large models in excess of 100 million cells.

Flexible well management control is provided through Python scripts. This allows users to customize asset-specific control strategies via a well-known and straight-forward scripting language. Alternatively, an internal optimization engine can manage the field subject to high level constraints provided by the user.
Recent 4S High Fold 3D Seismic Acquisitions in the Abu Dhabi Foreland of the Oman Mountains
Authors: Granser Harald , Novotny Bernhard , Fava Luca , Vermeulen Bruno
Published: November 2015

OMV and ADNOC commissioned WesternGeco to acquire a high fold, high density seismic program in the Foreland of the Oman Mountains, west of the city Al Ain. The objective of the survey was to acquire high quality 3D seismic data for a proper delineation and reservoir characterisation of structural and stratigraphic trapping geometries in order to identify potential exploration drilling locations.

The acquisition commenced Mid-2014 and was completed by early 2015. The program included two separate 3D areas covering 1800km². In addition, 700km of infill 2D lines were recorded to connect the two 3D surveys with modern 2D seismic and to complement the existing vintage 2D seismic grid. The seismic surveys were recorded with a Single Source Single Sensor design (4S) using WesternGeco's UniQ seismic acquisition system with single sensor geophone accelerometers (GACs) and single 80,000lb DX-80 vibrators. A Maximum Displacement Sweep was designed to enhance especially low frequencies resulting in a broadened amplitude spectrum. Operating up to 15 vibrators simultaneously allowed a very efficient seismic data acquisition but needed the implementation of the correct separations and slip times to ensure the data was not contaminated. The 18sec custom designed broad bandwidth sweep (1–120Hz) enhanced the S/N ratio in general and improved the data quality of the deeper target levels due to the input of low frequencies (below 10 Hz).

Sufficient azimuth, high fold, long offsets, broad bandwidth as well as optimum random noise reduction and increased spatial resolution was required to improve data quality. Therefore gaining more value with advanced seismic attribute analysis and enhancing the illumination of deeper zones in order to meet the objectives of the seismic.

On the logistical side, high flexibility was needed to allow complex and dynamic fleet grouping to maximize productivity. Any cross-talk noise between two different sources was managed using Managed Source and Spread (MSS) time and distance rules, which were based on the target characteristics. Acquiring dense 4S seismic required detailed planning to ensure operational safety and to achieve the planned fold coverage, especially in areas of dense infrastructure. The processing sequence for the high fold, high density 4S pre-stack seismic totalling 160 TB of data – 16 billion traces, was designed to effectively remove noise and preserve signal fidelity in the pre-stack data to ensure an optimal imaging and resolution of the geological targets. Due to the dune environment in the area, the application of optimal static solutions was an essential processing step. The good sampling of the noise in the raw data by the high density and high fold acquisition enabled a successful noise suppression performance and resulted in improving the image of the geological signal.
Andragogy Applications in ADCO Leadership Programmes
Authors: Flahive Tadhg
Published: November 2015

Objectives/Scope

This paper examines the fundamentals of learning styles and their current application in leadership programmes at ADCO. A variety of learning style models are presented along with how they have been incorporated into content instructional material. Implications for successful leadership interventions are examined and feedback from past programme participants on the effectiveness of the incorporated learning styles is clearly outlined.

Methods/Procedures/Process

The three main learning modalities: visual; auditory and kinaesthetic are put into practice using appropriate learning style checklists. Learners' learning style preferences are identified and programme materials are designed to address this diversity. The best instructional approach, regardless of subject matter or grade level, is a deliberate multisensory approach. Three of the learning style models most frequently cited in literature - Myers-Briggs Indicator, Kolb's Learning Style Model, and Honey-Mumford Model are practically applied in ADCO leadership programme delivery.

Results/Observations/Conclusions

Results from post-programme evaluations, participant surveys and facilitator observations indicate that learners must be involved in the planning and evaluation of their instruction. For learning to be truly effective it must take place around current work problems and must have job relevance. Programme facilitators must move learners out of their comfort zones and provide challenges. It is also worth remembering that no one learning style is better or worse than any other. All styles have their own advantages and disadvantages. Learning Agility is of paramount importance i.e. the ability to learn from past experiences and mistakes and transfer that learning to current situations. This paper demonstrates that learners learn best when they are allowed to: test concepts in ‘first time’ situations; engage in concrete experiences; observe and reflect.

Novel/Additive Information

This study provides practical tips and strategies that address the full spectrum of learning styles that can be used to enhance any leadership programme within an organization. Activities provided are mapped onto the aforementioned three learning style models. Feedback from participants in past ADCO learning interventions are taken into account when planning the activities used in current leadership interventions within the organization.
Produced Water Re-injection (PWRI) - Case Study from On-shore Abu Dhabi
Authors: Mahmoud K. , Al Tenaiji A. , Al Sharafi M. , El-Abd S. , Abdou M. , Hafez H.
Published: November 2015

Water production normally increases as field gets more matured; especially for fields developed via water injection or natural aquifer support. Handling water production is always a challenge from both financial and environmental prospects. The field under study is a giant oil and gas producer in Gulf area. Before embarking on the PWRI project, the routine way to handle the field's water production (~65 Mbbls/d) was to dispose through dedicated wells drilled only for that purpose and completed as open hole in Dammam, Simsima and UER formations. On the other hand, the water injection project sourced by water supply wells drilled and completed with ESP's through the same formations.

In 2010, PWRI project was commenced through replacing the aquifer water injection by produced water re-injection in one of the water injection clusters without water treatment. Since then, about 22–29 Mbbls/d of produced water are being injected through four water injection wells. After commencing the project, it was very crucial to assure that, no injectivity impairment due to produced water re-injection in addition to wells' integrity.

The water injection performance was closely monitored as WHIP and injection rate and using some techniques like Hall plot to detect any injectivity impact. Pressure fall-off tests (PFO) were frequently performed to detect any formation damage associated with PWRI. Moreover, PLT was performed in one of the wells before and after switching from aquifer water to injection water. The two logs were compared and proved that, there is no change in the injection profile across the horizontal section of that well. Corrosion logs were also utilized showing that, no integrity issues related to PWRI. As of now, some 24 MMbbls of produced water were injected with no impact on wells' injectivity or integrity.
Improving Asset Management at Process Plants Through UAV (Unmanned Aerial Vehicle) Inspections
Authors: English David
Published: November 2015

Technology remains at the forefront in taking the Oil and Gas industry forward and will provide solutions to future challenges. Companies adopting new technologies to solve existing problems will answer upcoming challenges facing the industry, especially those that provide significant cost savings and increase safety levels.

With the safe operation of onshore and offshore oil and gas assets always having top priority, together with high demands placed on Operators to increase production and maximize returns, increasingly the industry is using Unmanned Aerial Vehicles (UAVs) to inspect process plants that are generally inaccessible during normal operations. The latter typically comprises online onshore and offshore flare systems, towers and columns, flare support structures, splash zones and underdeck areas.

UAV technology is an innovative, safe and highly cost effective way to perform inspections without the need to shut down the facility, especially with regard to online flares when traditionally the only way to inspect them was visually during a shut-down. The major drawback with the latter is that any problems with the flare could only be identified during the shut-down and (unless operators held a stock of spare parts for these bespoke units), it would be necessary to re-commission the flare system and operate it for a further period until replacements had been delivered hence causing the expense and inconvenience of an additional shut-down.

Splash zone and underdeck inspections require specialist rope access teams, scaffolding and relatively calm weather conditions. The major drawbacks here are manpower levels, bedspace on assets and duration to set-up and disassemble equipment required to undertake and assist with inspections.

UAVs are increasingly being used by international Oil and Gas operators to inspect flares and other process plants whilst online so that a replacement tip and/or spare parts can be ordered in advance, or any necessary remedial work identified and planned in a controlled and coordinated manner prior to a planned shut-down.

UAVs are also used routinely for preventative maintenance inspections in splash zone and underdeck areas.
Managing Contractors and Subcontractors HSE Performance during Plant Turnarounds
Authors: Murthy Venkatesh
Published: November 2015

Plant Turnarounds (TA) are by themselves complex maintenance projects and a back to back turnaround in the Company in 2012-13, without any doubt, threw many challenges that was to be managed well to achieve very stringent HSE targets. This challenge lead the TA core team to an innovative and proactive method on the HSE management aspects that lead to every Contractor employee going back unharmed after 75 days of hard work. The startup of the Ethane unit crackers (EU1) in a record time of 28 days and 18 hours could only be achieved with the philosophy of "First time right" principles embedded within the activities and HSE and Quality Plan, which was executed well by all the team members including the Company leadership team, the employees and above all the Contractor employees who embraced this approach enthusiastically.

This paper aims to present, in a practical approach, the application of basic HSE principles and HSE management elements to the Management of Contractors and Sub-Contractors for a Major turnaround of Olefins and Poly Olefins Plant in the year 2012-13. This application can be understood and emphasized in the various stages of a turnaround: planning, pre-turnaround, shutdown, maintenance itself, commissioning, and startup of the plants.
Integration of Drilling Services, the Key to Excellence in Design and Execution
Authors: Al Suwaidi Muna , Al-Mohammad Mohammad , Al Shamsi Juma , Al-Reyami Mazin , Amanov Batyr , Hariri Nour , Sharma Prateek , Husien Mohammad
Published: November 2015

Abu Dhabi Company for Onshore Oil Operations (ADCO), one of the major Oil and Gas producers in the United Arab Emirates embarked in a new challenge to drill and exploration well in a new field that had only one offset well drilled in the 1980's. ADCO planned to have a step change in how to manage risk, engineering and operations in order to enhance drilling performance and reduce non-productive time while maintaining the highest HSE standards. A detail risk management plan and engineering process was developed and the main drilling services were bundle for the most critical well sections 12.25″ and 8.5″ in order to guarantee seamless operations.

The results of the implementation of this methology as well as the new initiative based on an active participation and cooperation between ADCO and the Drilling Service Company in all the phases of the well were outstanding and exceeded management expectations with regards to enhancement in drilling performance by optimizing ROP; reduction on NPT by reducing wellbore stability problems; ensuring high quality data acquisition; minimizing well cost.

The excellent results achieved in this exploration well included safely drilling and in an efficient manner, considering that very limited historical data was available, the power of drilling services integration proven to be the foundation of success. Other important achievements were the use of the latest logging technology to extract the formation fluid from tight formations in an optimum time; without any doubt drilling the 8.5″ section was the most challenging due to the expected concentration of H2S (~27%) with an increase of 2.3 times the ROP compared to offset wells; this was exceeding ADCO's expectations.

The aim of this document is to describe how the risk management plan was integrated into the drilling program from the planning phase to the operation phase in combination with the technical expertise and drilling technologies fit to propose provided by the Drilling Service Company the knowledge and experience of the operator lead to develop specific solutions for the main risk and challenges of drilling this exploration well. The paper also describes how the use of the bundle service model which used to integrate all drilling services which became a key factor during the critical stages of the execution phase.
Efficient Use of Data Analytics in Optimization of Hydraulic Fracturing in Unconventional Reservoirs
Authors: Temizel C. , Purwar S. , Abdullayev A. , Urrutia K. , Tiwari Aditya
Published: November 2015

Hydraulic fracturing operations affect reservoir flow dynamics and increase production in unconventional tight reservoirs. The control of fracture growth and geometry presents challenges in formations in which the boundary lithologies are not highly stressed in comparison to the pay zone, thus failing to prevent the upward migration of fractures. Several factors influence the growth and geometry of fractures, including reservoir, wellbore, and fluid/proppant parameters. Successful results require a thorough knowledge of reservoir parameters, including stress distribution and the appropriate use of corresponding wellbore components and fluid/proppant. The success of a hydraulic fracturing treatment is highly correlated with control of the created fracture geometry.

This paper discusses a study in which a numerical fracture model is used to design the fractures in a tight oil reservoir. Fracture treatment designs include the selection of fracturing fluids, additives, proppant materials, injection rate, pumping schedule, and fracture dimensions. Using the fracture model, a statistically representative synthetic set of data is generated for each parameter to build data-driven models.

The performance of the data-driven models is validated by comparing the results to a numerical model, and considering the significance of parameters, including size, number, location, phasing angle of perforations, fluid and proppant type, rock strength, porosity, and permeability on the fracture design optimization using various fracture models. Data-driven predictive models are generated by using neural networks (NN) and support vector machine (SVM) algorithms. Optimum values of model parameters are also investigated.

The SVM and NN models are used to optimize the fracturing treatments per well, and are evaluated based on accuracy and computational complexity. Based on the performances of the models, model parameters are adjusted to obtain fit-for-purpose well-based hydraulic fracturing models.
A Novel Approach of Using Phosphate-spiked Smart Brines to Alter Wettability in Mixed Oil-wet Carbonate Reservoirs
Authors: Meng W. , Haroun M. R. , Sarma H. K. , Adeoye J. T. , Aras P. , Punjabi S. , Rahman M. M. , Al Kobaisi M.
Published: November 2015

Smart waterflooding (SWF), an emerging EOR technique, was first investigated in sandstone reservoirs. However in recent years, the effect of smart water on carbonate reservoirs has gained wide interest. Despite the increasing number of research and publications in this area, the mechanism enhancing the recovery is still not fully understood. Wettability alteration and reduction in interfacial tension (IFT) have been identified as the two most dominant mechanisms. Divalent ions such as sulfate (SO42-) are found by many investigators to show promising results during SWF. However, limited research has been carried out to investigate the effect of trivalent ions. The objective of this study was to investigate the potential of phosphate (PO43-) spiked brines as a viable EOR technique in tight carbonate reservoirs.

Seawater with different dilution factors and varying concentration of phosphate ions were investigated against non-phosphate brines. Impact of these brines on wettability alteration was qualitatively monitored by tracking the rate of contact angle change on several aged-carbonate core samples subjected to varying aging periods. Various designed phosphate brines were tested at elevated temperature of 90 °C, and IFT was also measured at both ambient and elevated temperature (90 °C) to complement our findings.

To identify the impact of phosphate ions on wettability alteration due to brine/crude oil/rock interactions, carbonate core samples were prepared having initial contact angle ranging from 130° to 160°. The rate of contact angle change observed ranged from 9° to 36° as a function of varying composition of smart brines. A slight decrease in IFT was observed when lower salinity brines were used without phosphate. Phosphate spiked brines show a near surfactant reduction in IFT, compared to the low salinity brines. Smart brines with higher concentration of phosphate achieved better results than those with lower concentration.
Development of Reliability-Based Assessment Criteria Against Extreme Environments For Steel Fixed Offshore Structures With Significant Permanent Loading
Authors: Manzocchi Mark , Atia Mohamed
Published: November 2015

Many fixed steel offshore platforms in the Arabian Gulf are situated in shallow water and have a relatively high proportion of dead loading to environmental loading. As such their capacity is governed by the combined effect of extreme environmental loading and vertical dead loading. Reliability-based assessment methods normally consider the probability of the lateral capacity being exceeded by the extreme environmental loading. This assessment is typically performed by considering the pushover capacity of the platform compared with the regional environmental hazard curve. Allowance is made for uncertainty in the capacity and load model when evaluating the reliability. In the presence of significant dead loading, and for some ultimate failure modes, the sensitivity of pushover capacity to dead load plays an important role in the reliability analysis.

This paper describes the methodology for reliability analysis against the extreme load hazard and which can be implemented into future assessment codes. Particular attention is focussed on the sensitivity of structures to high levels of dead load and how this may be incorporated into reliability analysis. The development of acceptance criteria for reserve strength ratios (RSRs) which depend on regional hazard curves and dead load is also described.
Comparison of Permeability Estimation Models Through Bayesian Model Averaging and LASSO Regression
Authors: Al-Mudhafar Watheq J.
Published: November 2015

To capture the most realistic reservoir description in terms of heterogeneity, it is essential to find out the most accurate approach for formation permeability estimation in non-cored intervals. The simplest and most common approach of data modeling is multiple linear regression that adopts stepwise elimination for model variables selection. However, that elimination has shown its weakness to efficiently handle the high number of predictors in a physical process. In this research, we adopt two modern statistical leaning algorithms for core permeability modeling given well log attributes and prediction in non-cored intervals of a sandstone formation.

The Bayesian Model Averaging (BMA) was adopted as a stochastic approach of data modeling and parameter selection in formation permeability modeling. Based on Bayes' theorem, BMA integrates prior distribution given the observed data in order to produce a posterior distribution of how likely the model is assimilating the data. In the computed BMA Occam's window, the best selected model has maximum posterior probability and minimum BIC; meanwhile, the non-influential predictors are eliminated when the probability of a nonzero predictor coefficient is less than 50% for the best sampled model. Conversely, the same procedure was done through the LASSO regression that considers penalized least squared equation for data modeling and non-influential factors removal. Results of the two algorithms were illustrated, discussed, and depicted for efficiency comparison in terms of their modeling and prediction accuracy. In addition, the two models were statistically validated based on observed-predicted response matching.

Both BMA and LASSO have led to very accurate modeling and excellent matching between the observed and predicted core permeability. The adjusted R-squared and root mean squared error are highly encouraging with slight preferrnece of LASSO on BMA.

The novelty of Bayesian Model Averaging comes from its stochastic design to generate multiple models taking into account the data uncertainty which leads to finding find the optimal fit between core permeability and well log attributes. Also, the LASSO regression has led to better results than BMA with the same observed-predicted response matching. Both of them have overcome the multicollinearity between two pairs of predictors. Consequently, BMA and LASSO are efficient approaches for multisource permeability modeling with high dimensional predictors.
Directional Wells Anti-Collision Technology Based on Detecting the Drill Bit Vibration Signal and its Application in Field
Authors: Yin Bangtang , Liu Gang , Liu Chuang
Published: November 2015

With the deepening of exploration and development of onshore and offshore oilfields, cluster wells and infill wells are more and more popular. It will greatly increase the possibility of well collision during the drilling and would have great harm to drilling and the production of oilfield. The normal detecting technique of anti-collision is based on the measured well trajectory data and the judgment on the abnormality during drilling. The error of measured data and the uncertainty of downhole situation will result a high risk of collision. Based on detecting the drill bit vibration, a new anti-collision technology is proposed. Firstly, the acceleration sensors are installed on the casing head of risky well to collect the drill bit vibration signal transmitted by the formation and casing. Secondly, the signals are feature extraction by the calculation analysis software based on the time domain analysis and frequency domain analysis to recognize the approach motive of the drilling bit to the risky well. Thirdly, the characteristic signals are shown in real time. When the characteristic value is greater than the threshold value, an alarm will be given for the directional drilling engineer to do the anti-collision scanning in time and decide whether or not to change the well trajectory. This technology was applied in an offshore block in Bohai Oilfield and some fields in South China Sea. The results showed that the risk casing head vibration signal induced by drill bit vibration had a characteristic frequency range and the vibration signal characteristics were related with the distance between drill bit and the risk casing definitely. The vibration signals at the drilling casing head were very strong when cement plug was drilled, which could be used to judge whether bit was close to the cement sheath and casing of risky wells. The signal amplitude acquired at the casing head of risky well declined with the increase of distance between the drilling well and risky well. It can be used to judge the risk of wellbore collision. The results of field tests showed that new technology could monitor the well anti-collision and alert. It can improve the cluster and infill drilling effectively.

This is a new anti-collision technology based on detecting the drill bit vibration signal collected by the acceleration sensors installed on the casing head of drilling and risky wells.
Creating Value from Flared Natural Gas
Authors: Layfield Martin
Published: November 2015

Five percent of the world's gas supply is currently being wasted through flaring and venting. This is equivalent to about 110-140 billion cubic metres of gas which is the combined gas consumption of Central and South America in 2014. Gas flaring releases toxic components and green-house gases into the atmosphere that can have harmful effects on the health and well-being of local communities and contribute to climate change. In 2011, the USA became the fifth largest flaring nation in the world due to associated gas being flared from oil field production with the largest amounts being flared in North Dakota.

Capture of flared gas presents an opportunity to reduce the environmental impact as well as providing an economic opportunity. The gas captured can be used to create new value chains that can not only benefit the industry but also people's quality of life.

Technology has been developing for many years to attempt to tackle the problem specifically where small volumes of gas are being flared. In 2014, regulations in the USA were tightened on gas flaring specifically in North Dakota with oil operators having to put in gas capture plans in place for new oil wells being drilled. Capturing the flared gas presents an opportunity for oil operators to reduce the environmental impact as well as providing an economic opportunity to generate an additional revenue stream.

During 2014/2015, break-throughs were made by new suppliers coming into the market who have successfully installed new micro-LNG technology in North America to eliminate gas flaring at the well-head. Costs of the these micro-LNG technologies have reduced to the point whereby it is now possible to install these technologies cost effectively converting gas streams of less than 1 MMscfd into LNG which can either be utilised locally for drilling rigs or transported by truck to users further away.

The paper will present a range of technologies, including micro LNG, Compressed Natural Gas, Natural Gas Hydrates (NGHs), conversion methods and novel concepts that could be applied to capture and utilise flared and vented gas. It will look at the techno-economic concepts of specific cases at small scale. New features of the technologies will be highlighted and economics will also be given for the different technology options.
Chemical Looping Combustion: an Emerging Carbon Capture Technology
Authors: Snijkers Frans , Jing Dazheng , Jacobs Marijke , Protasova Lidia , Mattisson Tobias , Lyngfelt Anders
Published: November 2015

Chemical looping combustion (CLC) is a promising technology for energy production with inherent capture of carbon dioxide at minimal energy penalty. In CLC, oxygen is transferred from an air reactor to a fuel reactor by means of a solid oxygen carrier. Direct contact between air and fuel is avoided, resulting in an undiluted CO2 exhaust stream. As such, CLC was picked up recently as a high potential carbon capture and storage (CCS) technology. While initial focus was on storage projects, CO2 is more and more considered as a valuable chemical substance for enhanced oil/gas recovery projects as well as for the production of chemicals, polymers or building materials.

A critical aspect of the CLC technology is the oxygen carrier performance which has a very strong impact on the economic viability. Parameters such as particle size, density, porosity, strength, attrition resistance, reactivity, environmental aspects and cost, define the performance of the oxygen carrier. The first generation oxygen carriers was Ni-based. However, due to cost of nickel and toxicity, a search for Ni-free oxygen carriers was conducted with similar or superior performance in CLC. This lead to the development of Cu-, Fe and Mn-based oxygen carriers, that demonstrate the beneficial oxygen uncoupling effect, with complete fuel conversion as a result.

In this contribution it is shown that the industrial spray-drying technique is a very versatile and scalable technique for the fabrication of oxygen carriers. New and promising oxygen carriers with varying compositions, good fluidisability, high sphericity, high attrition resistance, and homogeneity on the micro-scale have been synthesized. Different materials such as perovskite type materials based on calcium-manganate, magnesium manganates, copper based materials, and iron manganates have been investigated for their performance with promising results towards complete combustion and high attrition resistance.