bluuebunny/crossref_metadata_2025 huggingface dataset:
3D Surface-Wave Estimation and Separation: Using a Closed-Loop Approach
Authors: Ishiyama Tomohide , Blacquiere Gerrit , Verschuur Eric
Published: December 2014

Surface-waves are often dominant in seismic data in a shallow water and land environment. Separating them out from the seismic data is of great importance for either removing them as noise for reservoir characterization, or extracting them as signal for near-surface characterization. However, their complex properties make the surface-wave separation significantly challenging in seismic processing. To address the challenges and adopt recent advances in seismic processing, we propose a methodology of surface-wave estimation and separation using a closed-loop approach. The methodology was successfully demonstrated on real 3D seismic data with mud-roll that is often dominant in a shallow water environment.
Applications of High-Resolution Imaging and High-Performance Parallel Computing in Unconventional Energy Recovery
Authors: Chen Cheng , Hu Dandan , Martysevich Vladimir
Published: December 2014

Two shale gas rock samples, from a Middle East shale gas play and the Eagle Ford shale play, respectively, were scanned using a nanometer-scale focused ion beam-scanning electron microscope (FIB-SEM). The geometrical properties were extracted and compared. The high-resolution image data were then processed and used as boundary conditions in the pore-scale GPU-accelerated lattice Boltzmann simulator (GALBS) for permeability simulation. The GALBS is based on the lattice Boltzmann (LB) method and optimized by graphics processing unit (GPU) parallel computing. Image processing showed that although the intrakerogen pores in the Eagle Ford sample had larger pore volumes compared to those in the Middle East sample, their morphologies were more laminar, which leads to higher friction to fluid flow and consequently gives rise to lower macroscopic permeability. GALBS simulations confirmed that the permeability was at the nanodarcy (nd) level in the Eagle Ford sample, while it was at the microdarcy (μd) level in the Middle East sample. Furthermore, anisotropy in the permeability tensor was observed in both shale samples. The computing speed of the GALBS is more than 1,000 times faster than the serial code and more than 10 times faster than the parallel code run on a standalone CPU, which suggests that many more samples can be analyzed given the same processing time. The combination of high-resolution imaging methods and high-performance parallel computing is a powerful tool for studying microscopic processes and upscaling. It provides for a more accurate estimation of the total stored gas and is helpful in the optimization of hydraulic fracturing treatments, which are aimed at connecting as many isolated intrakerogen pores as possible. The method presented in this study enables more accurate characterization of microscopic geometries and faster upscale transport properties, illustrating that unconventional energy recovery requires unconventional solutions.
A Computational Model for Simulating Proppant Transport in Wellbore and Fractures for Unconventional Treatments
Authors: Wu Hongfei , Madasu Srinath , Lin Avi
Published: December 2014

This paper presents a new and comprehensive model for proppant transport that is applicable inside both the wellbore and the fracture, along with an appropriate fast computational algorithm. This model can be used efficiently in both real-time and design modes of hydraulic fracturing processes.

The spatio-temporal proppant evolution is crucial in hydraulic fracturing processes as it directly affects production during shut-in and flowback. Yet, the computational cost is quite high because of multidimensional multiphase flow models, while most of the numerical approximations, such as the standard Galerkin finite element, are limited in their validity, prohibiting the numerical models from properly modeling the proppant dynamics correctly and practically.

This paper discusses a new one-dimensional (1D) two-phase flow model that accounts for the leading two-dimensional (2D) effects, such as proppant settling, resuspension, and bed transport, among others. Accounting for these effects helps ensure the conservation of momentum and mass conservation for the fluid flow for the proppant as well as for the proppant bed transport. The momentum conservation equations embed the interphase momentum transfer between the fluid and the solid phases, the momentum changes caused by proppant settling and resuspension, and the momentum exchange associated with the shear on the dynamic built-up proppant bed. This is accompanied by the mass conservations equations to include the fluid and the proppant mass flux induced by the settling and resuspension.

This computational model simulates proppant transport by using a first-order implicit scheme in time and first-order upwind scheme in space for the convection over a collocated grid for flow variables. The simulations demonstrate that the proppant bed is gradually formed and expanded downstream. These simulations also show that the formation of the proppant bed is caused mainly by proppant settling, and height change is determined by interactions among proppant settling and its resuspension during transport. Also, it is shown that the proppant properties strongly affect slurry transport and proppant bed dynamics.

The general results provide insight into the different mechanisms of the transport process, including gravitational settling and resuspension of proppant and proppant bed buildup and transport inside both the wellbore and fractures. This model provides a more pragmatic approach that enables field engineers to gain better insight into the proppant transport phenomena during a fracturing treatment.
Surface Safety System Enhances Gas Lift Safety and Optimizes Surface Line Architecture on Island Wells
Authors: Newton Daniel , Odom William , Burchell Graham , Kofoed Curtis , Harestad Kristian
Published: December 2014

The construction of drilling and production facilities for gas lift production and injection wells on artificial Islands provides a significant exposure to risk due to SIMOPS. Specifically, simultaneous drilling operations results in rig skidding operations over/near to live well cellars and production line trenches. This increases the risk of venting significant lift gas volumes to atmosphere in a manned area through dropped objects or other failures.

The authors describe a Lift Gas Safety System (LGSS) to be implemented that will prevent venting lift gas during both a dropped object and other unplanned incidents leading to loss of integrity (e.g. ESD). The system also provides benefits through improved annular pressure monitoring (APM) and confining barriers within the wellhead. Outlined is the implementation process by which the system was selected and which subsequently led to optimization of surface facilities from the well cellars through to the production manifold.
Integrity Management; Piloting of Gas-lift System in a Super Giant Field is building an accurate block in the development of effective strategy for well integrity management
Authors: Fahim Mohamed , Abdallah Dalia , Al Shemaili Sultan , Al Selaiti Iman Hamad , El Moghrabi Mohamed , Syed Aamir Aziz , Al-Kindi Zaid
Published: December 2014

In a super-giant field onshore Abu Dhabi; the production strategy is to maintain the sustainable capacity but due to increase in water production the need of artificial lift is mandatory to maintain the production plateau. However, accurate well integrity management in such field is critical due to fluid characterization, souring environment and field extension (35 X 20 Km).The selection of the artificial lift technique plays an important role in improving the ultimate recovery. However managing the integrity of the artificial lift wells is more challenging under the presence of H2S, CO2 and high P & T. The loss of production caused by integrity related issues and the need to determine specifications and accurate future integrity management plan lead to need for a gas lift pilot. For the future it is envisaged that integrity assurance plans needs to be an integral part of the field-development planning, ensuring that asset value is maximized.

More challenges will exist when dealing with Gas Lift as it is a long term artificial lift technique affecting well design for long life completion. Therefore, Gas lift was piloted to better understand real integrity challenges and measure corrosion trends with time to gain operational and technical experience and to compare them with initial theories.

The pilot was monitored closely with intensive program. An optimization process was followed, assisted by modelling. Although the initial thought that the corrosion might affect the top part of the completions because of the injected gas specification, but the time-laps corrosion logs gave a completely different and unexpected picture. The pilot results enabled the overall project to be concluded; the lessons learnt from the pilot were captured and used as building block for the full-field development options.

The paper describes the pilot results, the integrity challenges and the contoured problems, the philosophy of monitoring the corrosion evolution, the findings and how it was different from the initial expectation. Finally the clear impact on the integrity management process to ensure proper long-life well design and completion strategy.
Breakthrough in Field Development Planning of a Complex Reservoir by Designing and Drilling Highly deviated Wells Using Integrated 3D Geomechanics.
Authors: Azim Shaikh Abdul , Al-Awadi Abullah , Hussain T. , Al-Blayyes Mariam , Al-Anezi Salah , Al-Saad Bader A. , Imtiaz Saad , Shinde Ashok , Perumalla Satya
Published: December 2014

Zubair Formation is the deepest producing Cretaceous reservoir in North Kuwait. This 1,400 ft thick formation was deposited in deltaic to paralic depositional environment with complex sand/shale sequence, structural geometry, mineralogical composition and lateral extent. Drilling wells of any profile has witnessed high non-productive time due to severe wellbore instability issues in the form of stuck pipes, tight holes, hole pack-offs and jarring/fishing operations. So, a number of vertical wells were drilled to drain the reservoir– an economic challenge. Current strategic goal in this matured reservoir is to exploit multiple but thin pays by maximizing reservoir contact with high angle multi-lateral wells.

An integrated 3D Geomechanics study was carried out in two phases. In the first phase, responsible failure mechanisms for wellbore instability were identified: stress induced breakouts, washouts and cavings, failure and fluid invasion associated with shale bedding planes at high deviation and osmotic pressure transmission between Zubair shales and drilling fluid system. Water sensitivity of clays and presence of micro-fractures were also studied on cores of this trouble making formation. In the second phase, calibrated well based 1D Geomechanical models; 3D structural model with high definition faults, facies models indicating lithological changes and drilling experience of latest high angle wells were integrated into a 3D Geomechanical model. The 3D model was tested with data from several offset wells and it was capable of explaining the wellbore failure of these wells. This 3D geomechanical model also helped in predicting mud weight window for any proposed high angle well trajectories.

Mitigation measures from the study included drilling with Oil Based Mud or High performance water based mud systems with model derived mud weights, micronized sealing polymer to seal-off the laminations and micro-fractures, marble grade Calcium carbonate or resilient graphite to plug wider fractures and high salinity of mud to avoid time-sensitive osmotic flow.

After implementing these recommendations, six horizontal wells have been drilled successfully. The study has given further confidence to implement an aggressive field development plan for optimal depletion.

The paper discusses complex reservoir architecture, drilling complications and how the integrated study helped to achieve a breakthrough in development planning.
Nodal Analysis for a Transient Production System—Principles and Application
Authors: Zhou Wentao , Banerjee Raj , Proano Eduardo
Published: December 2014

Nodal analysis is the standard technique used to evaluate the performance of integrated production systems. Two curves represent the capacities of the inflow and of the outflow, and the intersection of the two curves gives the solution operating point. Limitations of traditional nodal analysis include that results are offered only at a snapshot, not as a function of timeinflow performance relationship (IPR) models are limited, with none available for shale gas wellsanalysis is performed on a well-by-well basis, with no account of multiwell interference.

We propose a new nodal-analysis method that enables the study of transient production systems in a multiwell context and at different timesteps, with IPR models generated from a high-speed semianalytical reservoir simulator and outflow curves output from a steady-state pipeline simulator. The use of analytical reservoir simulation allows accurate, reliable modeling of the real inflow system, including deepwater and unconventional wells. The new approach studies the time-lapse behavior of the system, with consideration of production history and neighboring well interference.

This new method enables the study of transient deliverability at the wellhead, where the measurement is usually available, and shows the time-lapse relationship between wellhead pressure and production rate. We provide examples of wellhead deliverability and choke management and explain advantages of the method with case studies involving tight and shale wells. The method is also applied to design and optimize artificial lift in unconventional wells and to study the method's validity over time. In addition, we discuss an example of operational well dynamics using time-lapse nodal analysis.

Additionally, this new method generates discussion about some concepts that are often taken for granted. For example, what should be the definition of IPR in a transient production system? On the IPR curve, is the zero-rate pressure the reservoir pressure? Can IPR curves at two different timesteps cross each other? Finding the answers to these questions will help us better understand production systems.

The commonly used productivity index (PI) method is reviewed and compared with the new method. Results show that the PI method should not be used when well operational conditions change.
Field Development Plan (FDP) Optimization of a Giant Field for Plateau Extension and Recovery Improvement
Authors: Azoug Youcef , Patel Harshad
Published: December 2014

This paper discusses a revised field development plan (FDP) of a giant complex carbonate reservoir located offshore Abu Dhabi which has been producing for more than 30 years. In recent years the target production of the field was raised. However, the target production plateau length and recovery factor remained high. This ambitious vision created a new environment and new challenges for field development.

Previous work has included a number of innovations (1,2,3): Implementation of a line drive pattern requiring a substantial drilling programIntroducing drilling from artificial islandsDrilling long extended reach (ERD) and Maximum Reservoir Contact (MRC) wellsIntroducing inflow control devices (ICDs) to maximize sweep and recovery, including advanced completion design workflowsIntroducing workflows to maintain evergreen simulation models

The paper describes the current work to optimize the development plan to extend the production plateau by many years and improve recovery. Detailed sector models have been used to facilitate the large number of required simulation runs. Sector models ran more quickly and provided the opportunity to test many development options and scenarios. This technique allowed focus on specific regions of the field, to improve their development scheme, before moving to other regions in a sequential manner. The findings from those sector models were then incorporated in the full field model (FFM).

In this paper we present the method used to optimize the plan by sector: Optimize well spacing and configuration, focusing on the advantages of infill drilling for improved aerial/vertical sweep efficiencyOptimize drilling timing for infill wellsOptimize vertical well placementOptimize injection strategy

An optimized field development plan is proposed where the desired production rate and plateau length are met while recovery is improved. The optimized solution involves a proposed infill drilling strategy and corresponding injection strategy. The injection strategy includes optimization of the future target reservoir pressure to achieve the best field performance.
Optimizing Waterflood Management in a Giant UAE Carbonate Oil Field Using Simulation-Based Streamlines
Authors: Khan Sameer , Al Zaabi Noura , Jani Zankar , Tariq Syed , Tee Aaron
Published: December 2014

Streamlines have been acknowledged as a powerful tool for modeling and optimizing waterfloods in oil reservoirs. Streamlines provide visualization of reservoir fluid flow and a unique way to conceptualize and quantify injector-producer well connectivity. Well allocation factors (WAFs) between injectors and producers as well as injection efficiency can be calculated and used to optimize water injection and reduce injection water cycling while focusing on maximizing oil recovery. The objective of this study was to develop a methodology, tool, and workflow for optimizing pattern waterflood management and to demonstrate application in a giant offshore carbonate reservoir. This methodology utilizes history-matched simulation models to generate streamlines from the pressure field and fluxes computed by a finite-difference reservoir simulator, EMpower. A finite-difference simulator is more rigorous than streamline simulators in terms of its ability to model complex fluid flow, and therefore, provides a more realistic solution. The streamlines thus obtained take into account the detailed geology, well locations, phase behavior, and flow behavior of the history-matched models. This methodology utilizes the concept of pair "injection efficiency" (IE) and pair "voidage replacement ratio" (VRR) which was necessary for the subject giant oil field and is equally applicable to other fields.

The optimization process is started by generating streamlines and associated WAFs at the current time using the simulation model. The injection efficiency is calculated and injector-producer well pairs are identified with high and low IE. New producer rates are then calculated by increasing producer rates in high IE well pairs and decreasing rates in low IE well pairs based on a weight factor. The injector rates are then calculated by applying a target VRR to each individual well pair. This results in redistribution of injection and production rates in a more balanced/optimal manner. The process is repeated at regular intervals (e.g., yearly or quarterly) while simulation is run in the prediction mode. Results show higher total oil production rates or lower water production and water injection rates. The WOR versus cumulative oil production clearly demonstrates that the overall injection efficiency increases as the optimization process is progressed.
Mature Field Rejuvenation Through 4D Seismic Application: Experience From Study To Execution
Authors: Ferdinandi Fabrizio , Cozzi Mauro , Di Giorgio Christian , Pirera Francesca , Rizzetto Catia , Onwubolu Godwin
Published: December 2014

Time-lapse or 4D methodology, that uses repeated 3D seismic surveys to monitor fluids saturations changes in reservoir, is a recommended tool for reservoir management in particular in deepwater fields where additional investments must be carefully evaluated due to the associated costs.

This paper presents a real case of a successful rejuvenation project of a deepwater field in West Africa, supported by integrated 4D and reservoir 3D studies. The field, located in 800 m of water depth, has been producing for 10 years with a rate currently equal to the half of the FPSO nameplate capacity. In 2010 a seismic acquisition specifically designed for 4D purposes was executed and, integrated with the historical production data, led to a revision of the levels’ potentiality. Reservoir barriers and fluids movements, water and gas in particular generated by the injection, have been modeled based on 4D acoustic impedance differences and were supported by history matching on the dynamic model. The strongly integrated approach supported a volumes in place revision that drove a sidetrack campaign on two wells to reach undrained areas. The integrated study highlighted also the possible risk of water encroachment on one of the targets of the two wells, that was therefore considered as a secondary target in the sidetrack plan. The result of the drilling campaign, combined with near field exploration, confirmed the expectations and contributed to double the production back to the initial peak plateau rate. Lesson learnt on this successful integration among disciplines are presented.
Fracture Optimization Applying a Novel Traceable Proppant and a Refined Mechanical Earth Model in the Congo Onshore
Authors: Martocchia Francesco , Perfetto Raffaele , Saldungaray Pedro
Published: December 2014

Fracture stimulation has been adopted as an integral part of the completion in the "M" field given the results achieved in enhancing well productivity, as well as the positive impact realized on field development economics. The fracturing process has been optimized over the years through improved reservoir understanding and ensuing implementation of technologies to address the uncovered challenges. Changes to the fracturing fluid formulation to prevent damaging the water sensitive reservoir rock, as well as modified proppant schedules to mitigate proppant embedment are examples of this improvement process.

This paper describes the successful ongoing process of optimizing hydraulic fracturing designs in "M" field. By applying an integrated approach combining various technologies, it was possible to better understand fracture propagation and coverage of the target reservoir. Implementation of a novel non-radioactive traceable proppant allowed accurate frac height measurement at the wellbore. When combined with rocks mechanics derived from sonic logs it led to redefining the mechanical earth model and ultimately the completion and fracturing strategy in the field. The process will be illustrated with examples from a 3-well campaign recently executed onshore Congo.
Solving the Dilemma - Life Saving Appliances in Oil & Gas Industry
Authors: El Sanabary Mohamed Awad
Published: December 2014

The purpose of this document is to provide Oil and Gas Offshore Companies with guideline or Code of Practice for Evacuation, Escape and Rescue and Life Saving Appliances at Offshore Installations in general with some added focus on Lifeboats that can be expressed as Totally Enclosed Motor Propelled Survival Crafts (TEMPSC).

Lifeboats have been involved in a number of serious/fatal incidents during maintenance, operations, testing, and training including drills/exercises; e.g. Offshore Drilling Rig AD22 working Saudi Arabia in 2009 - when the lifeboat has inadvertently fallen into the sea with personnel inside.

This document is not covering the Mobile Offshore Drilling Units (Drilling Rigs/Barges) as they are covered under different legislation which is the Code for The Construction and Equipment of Offshore Drilling Units.

Same applies for all other types of Marine Vessels as they shall comply with the latest requirements of the International Maritime Organization (IMO) and Convention of SAFETY OF LIFE AT SEA (SOLAS) taking into consideration any grace period for any new requirements.
Fully-Coupled Surface Network Model with Stacked Multi-Reservoir Model of a New Abu Dhabi Offshore Field
Authors: Marir Boualem , Allouti Abdelkader , Cobb David O. , Bedewi Mahmoud
Published: December 2014

A new field in offshore Abu Dhabi is currently being developed by ADMA-OPCO by combining the production from six distinct carbonate reservoirs, each of which has different characteristics. The production and injection streams from all the reservoirs will be mixed and processed using common surface facilities (Offshore Super Complex).

The development scheme was optimized based on the integration of the available geological, seismic, petrophysical, and dynamic reservoir data into six separate reservoir models. The optimized development plan was defined for each reservoir using its corresponding individual simulation model, where all reservoir models are compositional with similar pseudo-components.

Because the field will be developed as a gas self-sufficient field with no gas export line, all the produced gas from the six reservoirs has to be managed within the field. After removing the fuel gas, part of the total produced gas is used for gas lift; whereas, the remaining gas is compressed and re-injected into reservoirs D, F, and G to ensure full gas balance.

The facilities are shared by all reservoirs, so to further enhance field-development optimization modeling, especially with gas-recycling requirements, an integrated, multi-reservoir model with surface network was constructed. In this model, the six reservoirs were fully coupled with a single surface network, including wellhead towers, production/injection pipelines, and the Super Complex layout. This was accomplished by using a next-generation simulator that allows both surface and subsurface equations to be solved simultaneously.

This paper addresses the steps followed and the challenges encountered and then summarizes the main outcomes. In addition, it provides a comparison with the results obtained from the single-reservoir models when run individually.

The results obtained from the integrated model were slightly different when compared to those of the individual models because of the newly developed surface EOS model and the impact of the network on the individual reservoir's performance. The integrated reservoir model (IRM) proved its advantages, especially for gas recycling, by eliminating the previous iterative runs performed to achieve the field gas balance and by its ability to make the most effective usage of both water and gas plans to maximize recovery.
Innovative Hybrid Rotary Steerable System Allowed Drilling a 6 in. Horizontal Hole Through a Carbonate Reservoir With a Record Dog Leg Severity of 13°/30m
Authors: De Grandis G. , Maliardi A. , Gioia V. , Paoli F.
Published: December 2014

This paper describes the successful field test of an innovative hybrid Rotary Steerable System (RSS) developed for high Dog Leg Severity (DLS) applications. This novel technology has been applied for the first time in Continental Europe to drill a sidetrack well in a sensitive area where the application of new technologies is strictly related to the commitment to minimize the environmental impact of well operations activities.

The sidetrack was drilled to optimize the oil recovery from a carbonate reservoir. A solution was needed to drill the 6 in. sidetrack horizontal well starting from a 7 in. casing window, which must be opened just below the top of the reservoir due to operational constrains.

The challenge was to reach the targets, identified by the reservoir geologists to increase the reservoir exposure and maximize the oil production, while ensuring an optimum borehole quality. This required an optimal trajectory design and an accurate directional drilling control to land the well in the shallower part of the reservoir, far away from the Oil-Water Contact (OWC). A 3D well plan was engineered, with DLS up to 10°/30m. In the past, similar wells were drilled with a Positive Displacement Motor (PDM), which often produced poor hole quality. The novel hybrid RSS used to drill the sidetrack well has internal pads that push against an articulated sleeve pivoted on a universal joint to point the bit in the desired direction, enabling high build-up rates and a smooth wellbore.

The field test demonstrated the reliability of the system which successfully drilled the 6 in. curve section with a maximum DLS of 13°/30m, yet with an optimum wellbore quality. The performance was further enhanced by using a Polycrystalline Diamond Compact (PDC) bit specifically designed for compatibility with such innovative hybrid RSS.

This paper describes the field test and the well engineering process that led to the successful application.
Improving Safety Risk Tools for Accidental Fluid Releases with High H2S Concentrations
Authors: Nilsen Sandra , Høiset Stian , Salaün Nicolas
Published: December 2014

Statoil has substantial experience from safe design and management of safety risks associated with hydrocarbons and CO2 handling. Modelling of accidental releases is an integrated part of the safety risk management process - to verify safe design, layout and tolerable risk.

Modelling tools for hydrocarbon releases are well validated and verified against experimental data. Safety analyses for projects where the content of H2S in the process stream is considerable have revealed that there is limited experimental data addressing releases of H2S rich hydrocarbons. It was observed that the computer tools can give substantially different results with respect to dispersion distances for the same accident scenario. The variations seem to be larger when the stagnant conditions are liquid or 2-phase.

The scarcity of experimental data for H2S rich fluids and variations in results in calculations give reasons to implement results from risk analysis with caution.

This paper will present the results from a literature study that has been carried out in order to start closing the knowledge gaps along with consequence calculations for relevant release scenarios. The object of the literature study was to identify relevant models, their strengths, and weaknesses together with a survey of relevant experimental data. The results indicate that there exist so called simple models and algorithms that can take into account H2S specific properties. However, there are very limited, if any, experimental data to verify the accuracy of the models. It also became clear that very few CFD codes can model the complex thermodynamic processes during expansion of H2S rich hydrocarbons. The same situation is applicable for jet dispersion where the fluid is mixed with ambient atmosphere.

As a result of this work it is recommended to establish more relevant experimental data.
Technical Integrity Management in Statoil
Authors: Refsdal Ingbjorn , Urdahl Olav
Published: December 2014

In today's business environment, technical integrity management is fundamental in order to meet expectations from stakeholders, both internally and externally. The term technical integrity is in Statoil defined as "A system or a facility's ability to function as intended and in accordance with regulations (regulatory requirements) and internal provisions".

Technical integrity is vital for safe and effective operation of our facilities. Managing risk in Statoil is everyone's responsibility, directly or indirectly.

This paper outlines Statoil's risk based approach to an integrated, cross-disciplinary system for management of technical integrity. The work was initiated in 2010 with the aim to develop and implement a new technical integrity management system for measuring and follow-up of the technical condition of various safety barriers. The systems to be included in this were well, production and transportation systems, and load bearing structures. This initiative was named TIMP – Technical Integrity Management Programme.

TIMP consists of:

A comprehensive competence programme A standardised work process to follow up and visualise technical integrity A methodology to assess the technical condition at equipment-, system and facility level An IT tool to visualise the technical integrity and assist daily work processes.

Details of each element of TIMP are further outlined in the paper, and the challenges and learning from the development and implementation of TIMP on various assets are summarized.
Immiscible Nitrogen Injection: A Challenging Experience on Depleted Naturally Fracturated Reservoir
Authors: Vazquez A. J. , Guerrero R. , Ancona M. A. , Hernandez R. , Colin G. , Rodney C.
Published: December 2014

Pressure maintenance through immiscible nitrogen injection has proved to be one of the best methods as a secondary oil recovery on depleted and naturally fractured light-oil reservoirs (NFR).

The 190 MMscfd of immiscible nitrogen injection project that is currently developed in the Antonio J. Bermudez Complex, a giant NFR in Southern Mexico, is the second large pressure maintenance project in Mexico, after the world famous Cantarell project. A lot of challenges dealing with injection well locations, injection rate control, fracture system effect on nitrogen breakthrough and impact on hydrocarbon gas contamination, have been managed the last six years of project performance.

A comprehensive description of the pressure data acquisition program, the importance of the real time and planned chromatography to monitor the reservoir performance, the methodology to determine the net oil recovery contribution and the methods to define the vertical and horizontal efficiencies are described in this paper focused on learning lessons and best practices.

The experience gained over the six years of the nitrogen injection project show that this process is beneficial to extend the life of a depleted light oil reservoir as remedial solutions for mature oil fields revitalization.
Fibre Optic Four Mode Leak Detection for Gas, Liquids and Multiphase Products
Authors: Worsley Jerry , Minto Chris , Hill David , Godfrey Alastair , Ashdown James
Published: December 2014

Many variants of pipeline line leak detection systems are in operation today on liquid or gas pipelines. These often rely upon a single leak detection methodology. This could include; CPM, Mass Balance, Acoustic, Flow or Temperature Monitoring. Latest developments in fibre optic technology now mean that a number of these methods can be combined in a single system. Fibre Optic Distributed Acoustic Sensing (DAS) is able to use the following measurands to detect within leaks seconds with a location accuracy of 10 meters.

DAS detects the following signatures of a leak; Acoustic Anomaly; Temperature Gradient, External Ground changes and Negative Pressure Pulse. By fusing these signatures together DAS is able to provide a sensitive yet robust and reliable leak detection solution. Added benefits of the system are also the traditional security aspects that help prevent as opposed to detect pipeline damage as well as Inline Inspection Gauge Tracking through the same hardware set.

This paper examines the methodologies used to detect leaks in all phases of products. Discusses the industry led tests conducted so far and provides real life evidence of leaks detected in the field.
Using Multiple Realizations from an Integrated Uncertainty Analysis to Make More Robust Decisions in Field Development
Authors: Hegstad B. K. , Sætrom J.
Published: December 2014

This paper describes the workflow for an uncertainty study for a field development case offshore Norway. It is a workflow where uncertainties in seismic time interpretation, depth conversion, contacts, fault scenarios, alternative conceptual models, facies models, relative permeability, schedule etc. are included in an automated way to generate multiple realizations (hundreds) of the geomodel and reservoir model. Hence all uncertainties in the geomodel are also included in the reservoir model explicitly, and are captured by the ensemble of realizations. Since structure, contacts and facies distribution are different from realization to realization the workflow ensures that the planned well trajectories are automatically adjusted accordingly.

Having such a workflow which can generate and manage multiple realizations makes it straight forward to get robust and realistic estimates of uncertainties in in-place volumes and produced volumes. It is also used for risk mitigation and decision support as e.g. to evaluated robustness of well placement, well number, top side capacities etc.

This automatic workflow made it easy to rerun the uncertainty study when new well-data arrived. It made it also easy to run sensitivities on any part of the reservoir modelling workflow to gain valuable insight. Furthermore, having such a workflow made it possible to do quick and simple soft conditioning on dynamic data (such as drill stem test data) or alternatively use the dynamic data as direct input to the geomodel.

Few real data from the field under study will be included. Those who are included are anonymized and scales on axes are masked.
The Role of 3D Rock Chips and Cutting Area Shapes in PDC Bit-Design Optimization
Authors: Chen Shilin , Grosz Greg , Anderle Seth , Arfele Rob , Xun Keshan
Published: December 2014

Almost all previous cutter force models assumed that cutting force was proportional to cutting area. Cutting-area-based single cutter force models have been extensively used in polycrystalline diamond compact (PDC) bit design optimization. This paper explains why cutting-area-based bit models failed to predict bit forces. A new cutter force model and a new bit model have been developed and are discussed in the paper. In the new cutter force model, cutting force is a function of the shape of the cutting area. Three types of cutting shapes are respectively modeled. In the new bit model, three-dimensional (3D) rock chips created in front of cutting face are modeled, meshed, and removed from the hole bottom by updating the hole bottom at each time step. To validate the new model, six different PDC bits were designed, manufactured, lab tested under controlled conditions, and field tested. Details from laboratory testing and field-test results are presented.
Successful Polymer Flooding of Low-Permeability, Oil-Wet, Carbonate Reservoir Cores
Authors: Bennetzen Martin Vad , Gilani Syed Furqan , Mogensen Kristian , Ghozali Muhammad , Bounoua Noureddine
Published: December 2014

The majority of polymer applications to date have targeted medium-to-high permeability sandstone reservoirs containing reservoir brine with moderate salinity and hardness. Polymer flooding for enhanced oil recovery has been field-tested in carbonates, but applications tailored towards oil-wet, low-permeability limestone rocks are uncommon.

This paper contains results from laboratory core flood tests performed on four strongly oil-wet limestone rocks from the Al Shaheen field, off-shore Qatar. The rock samples investigated had 25–30% porosity and 0.3–28 mD permeability; the reservoir brine had a salinity of about 120,000 ppm of which 10,000 ppm were divalent cations. The bulk fluid testing involved fluid compatibility tests, long-term stability tests, as well as rheology measurements. Three commercial polymers were screened, one of which successfully passed all the screening criteria. Core flood experiments were subsequently performed to determine relative permeability, adsorption, inaccessible pore volume, as well as permeability and mobility reduction. The crude oil had a viscosity of 8 cP at reservoir conditions, yielding a slightly unfavourable mobility ratio for the baseline water flood.

At concentrations of 500–1,000 ppm, the selected HPAM polymer gave rise to some mobility and permeability reduction, as expected, but it did not seriously plug any of the four low-permeability cores. The dynamic adsorption was very low, around 10–20 μg/g rock, the inaccessible pore volume was 15–20%, which is in line with industry experience, and the injectivity reduction was in agreement with ECLIPSE and UTCHEM simulations, which suggest that significant polymer degradation did not take place. The low adsorption is attributed to the strong oil-wetness of the rock. Since the polymer flows in the water phase, presence of a strong oil film likely prevents the polymer from adsorbing to the rock. The results from a subsequent water flood showed that inaccessible pore volume introduced by the polymer persists during the subsequent water flood; such a feature has yet to be incorporated in UTCHEM and ECLIPSE. In fact, the data revealed many features, which could not be adequately captured by numerical simulation tools.

The main conclusion from the laboratory work is that polymer systems with good viscosifying power can be tailored to recover oil from low-permeability carbonate rocks, pushing the permeability limit down to around 1 mD.
Major Key factors And Guidelines For Preparation Of Project Execution Strategy
Authors: Al Hammadi Nasser , Saud Shah
Published: December 2014

The fact that the majority of projects fail on at least one measure of success, and that billions of dollars in project waste is reported each year, suggests that there is a critical need for improving the way we manage these projects. The unrelenting truth is that the secret to more successful project management has been right in front of us the whole time - learning from the past and preparing for future. The best way to address the issue is thorough proper execution strategy.

The objective of this study is to identify major key factors & provide guidelines for preparation of successful project execution strategy predominantly in oil and gas industry where meeting the schedule is of utmost priority, especially in case of plant shutdown that is pre-planned for specific fixed period cycle to carry out preventive maintenance and unit replacement.

This study utilizes a Case Study approach from projects for data analysis statistics, Identifying major factors influencing Project Execution Strategy. Among various elements of Project Execution Strategy the Project Resources, Risk Management & Engineering Deliverable Review Strategy are focused providing in-depth analysis on 38 Major & 40 No's Technical project having capital investment of more than US$26 Billion.

Utilization of Resources Data Bank prepared based on various project and how it will help Project Management Team (PMT) to evaluate the resources requirement and subsequently the project duration based on available organization resources. The Preparation of Data Bank & their accessibility will help project management team to give quick analysis of project resources as well as project duration.

Further, Impact of Conducting Risk Analysis on project of complex nature is analyzed; a quantitative analysis on major 38 No's project provides the necessity of including the risk analysis as part of Project Execution Strategy. This research will provide a platform and source of guidelines for project manager's to produce efficient & SMART execution strategies for EPC Projects in particular for gulf region.
Stabilized and Increased Well Production Using Automatic Choke Control
Authors: Kittilsen P. , Fjalestad K. , Aasheim R.
Published: December 2014

Process fluctuations are often equivalent to lost production as the necessary margins to process constraints need to take into account the fluctuations. Better operation is achieved by reduced process fluctuations so that the average production may be closer to the constraints. This is achieved by automatic process control which also reduces operator load.

Wells which produce oil and free gas (coning) from the reservoir are sensitive to changes in operating conditions, and the gas and oil rates drift over time. This is natural because variations in coned free gas generate variations in wellhead pressure. This will in turn affect the production rate and the well drawdown. In manual operation, a common strategy is to operate with an excess of free gas or use artificial gas lift and manipulate the wellhead choke manually.

An automatic wellhead choke control solution is developed to reduce fluctuations and increase production rates. The two main elements in the automatic wellhead choke control are:

A robust measure of the controlled variable (i.e. the gas flow rate) A robust control strategy

Since the gas flow rate is not directly measured, a gas flow rate estimator was developed, with the premise that no hardware modification should be necessary:

The gas fraction in the well stream is determined from the pressure drop from the bottomhole to the wellhead The total multiphase well flow is calculated from either a venturi meter (if available) or the well head choke (based on choke pressure drop, travel, and characteristics)

The control strategy is to ensure fast corrections to keep the gas flow rate close to the specified set point, thus enabling a close-to-collapse operation of the established gas cone. The gas flow rate set point is specified to ensure that the well head pressure is sufficiently high, i.e. higher than the pressure downstream the choke.

The solution is implemented on several wells at various Statoil operated fields with gas coning into the wells. The solution gives stable well flow rates, and thus enables increased production. The operator workload related to well supervision has also been reduced. The method could also be applied to other that should remain constant, e.g. water cut, water flow, or GOR, as long as the quantity can be estimated (or measured), and will respond to well head choke manipulations.
ADCO Deploys the EFQM Excellence Model as a Management Framework for Sustaining Operational Excellence
Authors: Daoud Mohamed , Al Mansouri Bakheeta , Alaa Mohamed , Sulieman Amar Osman , Hegazy Haytham , Desi Hala , Al Bannay Nooran
Published: December 2014

Excellence became a necessity of our time topping the agenda of all professionals. As confirmed by our CEO in more than occasion; Excellence at ADCO is not a destination; it's a core value demonstrated as way of doing business.

The Excellence Journey kicked-off at ADCO since the inception as the company prides itself as a big advocate for QMS Systems in the Oil and Gas Industry. This was achieved by integrating all quality systems under the EFQM Excellence model. ADCO started in mid 90s implementing TQM principles led by our current CEO.

The recent implementation of the EFQM at ADCO came after the two updates of the model 2010 and 2013. Organizational assessment was conducted highlighting the areas for improvement (AFIs) which prioritized into a comprehensive action plan to ensure implementation across ADCO. The latest update is the adoption of the EFQM model within the oilfields piloted in the newly developed field (Qushawira).

The EFQM model is a practical, non-prescriptive management framework enables organizations integrates their existing and planned initiatives providing structure for the organization's management system. The model comprises of 3 components; the fundamental concepts, the 9 criteria and the RADAR logic.

Results and Conclusions:

The implementation of the EFQM model has materialized in enhancing the operational excellence culture. The management thinking and leadership style have moved to looking at the operational challenges as (AFIs) which made all leaders in a continuous search for new ways and methods of reaching performance excellence.

This was validated when ADCO participated in 2012 in the Sheikh Khalifa Excellence Award (SKEA) and achieved the Gold category in the Oil and Gas sector. Now, ADCO is preparing to apply for SKEA (2014). A lot have improved after winning the Gold Category in 2012 which qualifies ADCO to win higher category/ies in 2014.