bluuebunny/crossref_metadata_2025 huggingface dataset:
Accurate Drawdown Mobility Estimation Using Computational Fluid Dynamics Simulation
Authors: Yuan Peng , Wu Jianghui , Zhang Hao , Huang Xu , Mezzatesta Alberto , Zhou Quming , Elyyan Mohammad
Published: November 2017

Recent technological advances in formation testers enable them to deliver reliable and accurate pressure data by combining downhole automation with real-time control. Conventional methods to estimate drawdown mobility do not provide accurate results in very-low permeability (0.01 to 1.0 mD) formations. In recent years, Computational Fluid Dynamics (CFD) has emerged as a powerful tool to study fluid flow through porous media and provide an alternate way for estimating drawdown mobility and formation permeability.

This paper proposes a new method for estimating drawdown mobility using CFD simulation. This new method uses a diffusion equation to track the fluid flow. The drawdown rate is introduced using the boundary flux term.

After reviewing synthetic cases where the analytical solutions existed, CFD simulations were found to produce more accurate results than those from other approaches. The CFD model is then applied to various formations with a wide range of permeability and anisotropy. The results show that the proposed CFD model can simulate all the testing cases with a broad range of permeability values from very low (< 1.0 mD) to very high (> 2500 mD). In addition, the impact of various drawdown schemes and formation properties were studied using the CFD simulations.

The new CFD method has been tested and validated with synthetic and field data sets. Results clearly show that this method can handle formations with a wide range of permeability and permeability anisotropy. Results also show that the proposed method greatly improves the accuracy in drawdown mobility estimation, especially in low-permeability formations.
Partial Discharge Measurement in Transformer & Switchgear to Ensure its Integrity
Authors: Middya Mustakim
Published: November 2017

Electrical power network system is considered as a valuable asset. So it is important to manage such an asset with criticality criteria by adopting different predictive maintenance techniques to increase reliability (availability) and reduce direct & indirect costs. Such techniques constitute the basis for an effective asset management system, as they can ultimately decrease the electrical failure rate. HV transformers & switchgears are considered to be expensive and delicate components of the electrical energy network. Increasing load on transformers & switchgears causes the more stress on it. Continuous stress weakens the insulation and producing arcing called partial discharge (PD). Partial discharges seriously affect the reliability of transformers & switchgears. Electrical energy networks may experience transformers & switchgears failures because of insulation degradation. Failure of high voltage insulation is the No-1 cause of high voltage system breakdown. IEEE statistics indicates that electrical insulation deterioration causes upto 90% of electrical failures of high voltage equipment. The major and most effective tool to detect insulation deterioration, as is well known, the measurement and analysis of partial discharges. However, this technique is not as well accepted as one might expect based on its great benefit. Reasons behind it are (1) PD testing is a fairly new technology compared to usual Hi-pot test. PD testing has matured over the years and today it has already been proven to be much more powerful indicator for insulation defects compared to offline test like Hi-pot & Megger etc. (2) PD testing may be more powerful indicator for detecting insulation defect but it is also the most sophisticated test to be carried out. The interpretations of the result are extremely challenging and require vast experience to do further analysis. Once results are correctly interpreted, PD testing will give the best detailed diagnosis of the insulation condition of equipment compared to other conventional test. (3) PD testing is sophisticated and the cost of instrument is comparatively higher. Based on many advantages, this PdM technique is gaining popularity with time.

This paper describes PD theory, PD detection and analysis approach to the diagnosis of HV Transformers & Switchgears insulation system along with few case studies. The results of PD measurements performed on-line on HV transformers & switchgears insulation system, just after commissioning or after sometime in operation helps in identifying PD-generating defect. Decision is made by comparing reading with baseline and periodically recorded data.
Wellbore Stability Management to Avoid Serious Drilling Hazards in High Deviated Well-Application of Real Time Geomechanics
Authors: Al Hajeri Mishari , Al Safar Waleed , Gupta Pravind K. , Raturi Sushil K. , Al Zankawi Omran , Bojarah Khaled Hussain , Al Ghareeb Aisha Yousef , Al Aryan Ali Mansour , Naik Vinay , Shastri Mukesh , Belhouchet Mohamed , Abdessalem Abba
Published: November 2017

A geomechanical evaluation and monitoring programs was conducted in order to reduce non-productive time and drilling complications while drilling in a tectonically stressed area of Kuwait. Offset wells had experienced problems related to the tectonic stresses and associated faults, fractures, complex structures, and anomalous pore pressure. Additional challenges were faced due to complicated and highly deviated well designs where planes of weakness in the formation being drilled and their relative angle with respect to the well path become crucial factors in assessing stability of the borehole. Multiple failure mechanisms such as stress induced wellbore instability, invasion of drilling fluids into weak bedding / micro-fractures and osmotic sensitivity, are found to be the root cause of wellbore instability across reactive shale and other problematic formations especially during drilling of highly deviated wells.

To successfully achieve the above objective, it was prudent to be armed with proper assessment and understanding of wellbore stability along with optimizing the most appropriate drilling strategy. Five offset wells were assessed from Geo mechanical point of view in the area in order to simulate the back analysis of the borehole collapse in the unstable zones. The previous wells experience showed a high risk to drill the shales and depleted reservoir formation in one section, causing a high ECD in depleted reservoir which dramatically led to severe losses.

The planned well was monitored in real time through the control of the ECD and drilling parameters. Since shales in that section are unstable and tend to be plastically deformed, high mud weights were typically used. Based on the geomechanical inputs of the wellbore stability while drilling, new casing strategy was formulated taking into-account the wellbore stability input, drilling parameters and the mud rheology. The shale section was isolated with separate casing and well was successfully drilled to TD without any drilling complications and minimum Non Productive time.

Geomechanical modeling and real-time monitoring allowed the well operator to overcome serious drilling hazards and optimize the drilling practices. This application promises to open the prospect of drilling similar wells without complications and reduced NPT in Kuwait.
Create a Rock-to-Rock Well Abandonment Barrier without Swarf at Surface!
Authors: Joppe Lambertus C. , Ponder Andrew , Hart Daniel , Bruun Bjørn T. , Grindhaug Gaute
Published: November 2017

Section milling is a common method for casing removal during well abandonment applications where annular well integrity is compromised or questioned. The removal of casing by milling a window provides full access to the virgin formation, enabling placement of a rock-to-rock barrier.

Retrieving the metal cuttings (swarf) created by the milling process to surface and handling them on surface is a time-consuming and costly operation associated with health safety and environmental (HSE) risks. A joint operator/service company technology development project of a section milling without swarf to surface system now provides a novel solution.

This paper discusses the design, lab-testing and wellsite testing iterations that led to a fully functioning system for establishing a true rock-to-rock barrier without the nuisance of swarf at surface.

The new method entails milling in an upwards direction away from the swarf deposition. Currently, all section milling operations mill downwards. The system consists of the following components: taper mill, auger, section mill, emergency release disconnect, jet sub, left-hand rotating mud motor and torque isolation assembly.

The concept of milling upwards, mandated left-hand rotation to prevent casing couplings from backing off, paired with the desire to deploy on right-hand drill pipe resulted in designing and manufacturing of a custom-built left-hand mud motor. Developing a capable torque isolation assembly was not without hurdles; excessive vibration during early tests led to significant improvements to the torque isolation system, which now provides a robust solution. Creating the swarf proved to be the easy part. Downhole swarf management was more challenging, and an auger system was developed to mitigate the earlier issues encountered.

Multiple tests, evaluation and step-by step system improvements ultimately culminated in a fully functioning system, now ready for its first field deployment. A more efficient and cost-effective removal of casing by downhole deposition of the swarf created from the casing section milling operation, will reduce operational time related to plug and abandonment (P&A) operations. Multiple enabling technologies provided the stepping stones for this system and will be highlighted individually.
Campaigns of Opportunity – Rigless Subsea Phase III Well Abandonment Operations in the UK Continental Shelf
Authors: Canny Steven A
Published: November 2017

Subsea operations—from the need for multidisciplinary teams to delivering equipment and services in a harsh offshore environment—are inherently expensive. These costs are typically recovered through the reservoir production over a number of years. When production ceases, the cost of abandonment is absorbed as a liability, which leads to a stringent focus on cost efficiency. It is, however, an area where the opportunity to achieve significant cost savings through new technologies and an alternative approach to service vessel and campaign structure.

This paper describes a facilitating technology—the subsea wellhead connector, or SWC—that enables operators to undertake monohull and even rig-based subsea abandonment campaigns. Deviating from a semi-submersible rig to a monohull-based campaign has reduced vessel day rates and personnel costs by a substantial margin. To maximize the saving potential for rigless abandonment technologies and equipment, however, require collaboration between the operator and service provider.

The SWC latches and recovers all common 18.75-in. bore wellhead suspension systems. The system offers mechanical, abrasive, or explosive severance tools for plug-and-abandonment (P&A) campaigns and a small re-entry mandrel seal assembly for intervention. Deployment can range from vertically or horizontally rigged orienttions, and operations are limited by the remotely operated vehicle (ROV) limitations.

This paper presents four Phase III campaigns in the North Sea continental shelf as case studies. Each has unique challenges. Monohull vessels were used in the first 3 wells and the final campaign was run from a mobile offshore drilling unit (MODU)—this final approach brough rigless technology to a rig to further enhance operational capability.
Improving Observed Azimuthal Anisotropy for Fracture Analysis in a Carbonate Reservoir of Abu Dhabi
Authors: Vargas Jose Edgardo , Utami Y. P. , Sturko D. , Smith C. , Reddy P. , Glushchenko A. , Vasilyev P.
Published: November 2017

Most fracture characterization techniques using seismic data are based on seismic anisotropy analysis. Providing a more reliable dataset for such analysis should be considered during the entire seismic processing sequence. This case study demonstrates that the new techniques in seismic regularization of high dense, single-source, single-receiver (S4) seismic data along discrete azimuth directions with regular source-detector distance intervals (radial domain interpolation) can provide enhanced imaging through azimuthal velocity analysis, and deliver datasets for seismic inversion with improved noise attenuation. A comprehensive workflow is presented to improve the final image quality, and to preserve the azimuthal amplitude variation with offset and azimuth (AVOAz) for its analysis, which in turn can lead to the derivation of intrinsic rock property attributes for better reservoir management decisions & drilling plans. To compensate for the overburden effect and improves resolution at the zone of interest, a multi azimuth prestack depth migration approach resolved most of the effects of heterogeneities in the velocity field, which can be misinterpreted as azimuthal anisotropy.

The processing sequence for this dense seismic (acquired with 5×5 meter bin size, 1600 traces per bin), broadband survey in Abu Dhabi supports the understanding that azimuth-rich single-source, single-receiver acquisition geometries can provide advantages over conventional techniques (such as the use of receiver arrays or narrow-azimuth surveys) for the imaging, fracture characterization, and reservoir management of very subtle low-relief structures, in particular shedding light on the complex geological environments of carbonate reservoirs in the Middle East.
Intercultural Competency for Petroleum Professionals
Authors: Lau Hon Chung
Published: November 2017

As petroleum projects becomes more international, there is more need for the petroleum professional to communicate across cultural boundaries. Intercultural competency on the part of the petroleum professional begins with an awareness of three types of cultures at work in the workplace: national, corporate and personal. Based on proven research in the field of cross-cultural communication, we propose using the Cultural Onion Model (Smith, 1992) to interpret these three cultures. This Model uses the analogy of an onion with four layers to represent the four layers of a culture. They are Behavior, Authority Structure, Experience and Core. Within a culture, the core contains the values and assumptions from which a culture develops. We then show how differences in core values concerning inequality, individualism, masculinity and uncertainty avoidance can affect the other layers of a national culture. Next, we explore how differences in corporate core practices can affect the culture of different types of company. Finally, we explore the implications of difference in both national and corporate cultures on three work-related areas: communication, leadership and reward system. Methods that work well in one culture may not work well in another, hence the need for cultural adaption. Our model will help the petroleum professional to understand important aspects of national and corporate cultures to become more effective in working across cultural landscapes.
Overcoming Challenges to Reduce H2S Content in Sales Gas Transmission Pipelines
Authors: Allamaraju JagannathRao PrakashRao , Mukherje Rahul
Published: November 2017

This paper presents a case study highlighting actual implementation of technology advancements for removal of H2S (slipped from upstream gas plants) from sales gas pipeline at remote locations.

GASCO’s pipeline network is designed for sour service (250 ppmv H2S). The guidelines for design of sour service pipelines as stated in ISO 15156 have been complied with. One of the pipelines which supplies sales gas to major power plants on a continuous basis is of 48" (of Consumer) and is designed for sweet service. This consumer is normally supplied sales gas by another gas Supplier A. GASCO is required to supply sales gas to power plants during the emergency requirement / outage scenario of regular gas supplier A. Indeed, slippage of H2S due to upsets in upstream plant facilities may cause several technical problems for instance, corrosion.

Therefore, initial study focused on defining the corrosion implications of operating the 48" Pipeline with GASCO gas supply with up to 250 ppmv H2S.The main corrosion threat to the Pipeline is the risk of sulphide stress corrosion cracking (SSC).

Study of the Gas Supplier A of Consumer Pipeline records indicates that the pipeline is not exposed to H2S partial pressure of 0.05 psi (a) as required by ISO 15156.

The online H2S trends were reviewed for GASCO sales gas to assess the actual time of exposure.

Starting 2014 to Target 48" Pipeline Integrity, Process Safety (PS), enhancement in HSE and performance monitoring, GASCO embarked on an ambitious Project installing state of the art H2S Scrubbers systems to mitigate H2S slippage into the pipeline.

FEED was conducted to select the optimum Technology for H2S removal.

The H2S removal technology selected was Non-Regenerative type, metal oxide based absorbent catalyst for removal of H2S from the sales gas. These catalysts have to be replaced after a fixed duration of service life estimated based on inlet H2S content and flow conditions.

Owing to the size of the pipeline and the H2S content in the gas, the selected process of Non Regenerative technology has distinct technical and economic advantages over conventional regenerative processes. By virtue of the selected lead lag arrangement, multiple (three) train options and high SIL rated H2S analyzers, the usage of the catalyst is optimized and the overall system reliability, availability, maintainability and integrity is ensured for continuous operation without affecting the existing facilities.

The process is unique and one of its kind on major pipeline within GASCO sales gas network.
Experimental Investigation of the Underlying Mechanism Behind Improved Oil Recovery by Low Salinity Water Injection in Carbonate Reservoir Rocks
Authors: Alhammadi Mohamed , Mahzari Pedram , Sohrabi Mehran
Published: November 2017

It has recently been reported that the additional oil recovery that may be obtained by low salinity water injection (LSWI) is due to an interaction between the crude oil and injected brine. This mechanism, which is linked to natural surface active components of crude oil, is referred to as micro-dispersion. Previous studies have demonstrated the link between formation of micro-dispersion and the additional oil recovery in sandstone rocks but the existence of such links for carbonate rocks has not been reported before. In this work, we have investigated whether a similar oil/brine interaction can take place in carbonate reservoir rocks and whether that could lead to additional oil recovery by LSWI in carbonates.

Using rock and oil samples from carbonate reservoirs, a number of crude oil samples were first tested and ranked based on their ability to form micro-dispersion when in contact with low salinity brine. Two samples were selected; one with high and the other with low propensity to form micro-dispersion. A third oil sample was then prepared by removing the micro-dispersions from the oil sample with high propensity to form micro-dispersion. Using these three oil samples, a number of coreflood experiments were performed on the same relatively large carbonate reservoir core 3.8 cm in diameter and 30cm long. Both secondary high salinity flood and tertiary low salinity flood were carried out in each case to determine whether the presence of micro-dispersion was associated with improved oil recovery for this carbonate system.

In secondary high salinity water injection, in experiments using the three oil samples, all coreflood tests showed the same ultimate oil recovery. However, when the flood water was switched to low salinity, the highest amount of additional oil recovery was obtained for the oil that had shown a high tendency to form micro-dispersion in the fluid/fluid tests. The coreflood experiment that was performed with the treated oil sample (the oil sample which had its micro-dispersions removed prior to coreflood test), exhibited no additional oil recovery. The third oil sample, with a low tendency, also showed little improved oil recovery. Moreover, the pH and ionic composition analysis of the core effluents was found to be the same in all three experiments. This important observation indicates that the geochemical interaction played little role in the observed improved oil recovery compared to the micro-dispersion mechanism.

The novel information obtained for carbonate reservoirs in this work helps us better understand the mechanisms involved in oil recovery by LSWI. This knowledge is important for developing screening tools for oil reservoirs that are being considered as potential candidates for EOR by LSWI.
Enhance the Run Life of Downhole ESP Equipment in Water Supply Wells
Authors: Mohamed El Sonbaty Tarek , Elmansour Ayman
Published: November 2017

More than 155 Electrical Submersible Pumps (ESP) are installed in water supply wells in one of United Arab Emirates – Abu Dhabi Onshore area fields (ADCO). The water supply wells producing wells are characterized by low reservoir pressures, high production rates, low levels of H2S and toxic gas. The produced reservoir formations mainly consist of soft limestone and with variable porosity.

This paper will highlight the major techniques used to boost ESP system run life and enhance reliability in onshore application. These techniques are as follow: Equipment selection - Redesigning equipment to adapt to reservoir parameters and productionUpgrading of ESP equipment, accessories, seals and consumables to withstand reservoir pressure and fluid propertiesOperation Practice Developing guidelines to enhance operation practice and test equipment integrity in workshopWell condition –Monitor the well condition and advice field production and operation team to schedule the well for periodic clean out and stimulation to enhance the production

The above technical enhancements made were to improve ESP performance in scale forming and corrosive environments. The focus will be on case histories to discuss what was implemented and the methodologies that were used to overcome specific challenges encountered with the use of ESPs. The analyses will overview ESP failures from the period 2011 to 2016.

These proposed solutions helped the in improving overall ESP system run life and reliability from 459 days (year of 2013) to 878 run days (year of 2016). It also helped the in reducing the MTBF (Mean to before failure) from 581 days (year of 2013) to 1079 run days (year of 2016). Additionally it reduced the OPEX by 35%, ESP failures in ESP water supply wells from 35 failures (2013) to 18 failures (2016), well down time, and potential HSE risk related to well intervention and work overs.(fig 01) Figure 1No. of ESP failures in water supply wells
Achieving Succession Management through the Identification and Positioning of Organizational Leaders Using Leadership Effectiveness Evaluation Tools
Authors: Okomgboeso S.
Published: November 2017

Objectives/Scope: The objective of this paper is to lay emphasis and sensitize organizations on the need to include leadership traits and skills assessment as a critical part of the recruitment process for the supervisors’ cadre; and to show that leadership traits and skills are important for people development, and succession management, using the result of a pilot study on leadership evaluation.

Methods, Procedures, Process: Through the application of quantitative and qualitative methods, leadership assessment of supervisors was obtained through their subordinates composed of trainees, local and expatriates employees of an organization in the UAE. A semi-structured survey questionnaires and interviews were administered on participants after obtaining the necessary approvals for the pilot study. The sample populations were made-up of 40 employees who were below the rank of team leaders. The questionnaires were designed both in English and Arabic Languages respectively. Questions to ascertain leadership behaviors were given to participants and the answers ranked on a Linkert scale of 1 to 5, where 1 and 5 represents extreme values of strongly disagree and strongly agree respectively. The questionnaires provided the quantitative data, while results from the interview provided the qualitative data. The composition of the participants included, technical, non-technical and human-resource department employees.

Results, Observation, Conclusion: The results revealed that leadership traits and skills are not regarded as part of main issues considered during recruitment processes and placement processes for supervisory positions. Recruitment processes for new entrants seem to focus more on technical competencies and less focus on leadership skills. There were those who possessed the leadership traits, and also those who lacked the traits needed to coach and develop future organizational leaders; especially, in an environment where societal culture has a huge influence on people. This paper recommends a continuous evaluation of effective leadership traits of supervisors at all levels in order to ensure that the right organizational habits are passed-on-to subordinates. Finally, this paper advocates for a detailed study to ascertain how leadership behaviors correlates with subordinates performances in an environment where social culture has a huge influence and how they can intermingle to enhance organizational efficiency.

Novel/Additive Information: The outcome of this paper will assist organizations especially those in the Gulf Region to develop the right tools for their recruitment processes. It will also assist them in developing an effective leadership trait assessment process which will enable them identify the right persons deserving leadership positions.
Optimization of Habshan-5 NGL Run-Down System
Authors: Muthukrishnan Murali
Published: November 2017

In line with ADNOC’s principle of increased performance, efficiency and profitability and, GASCO focus is to optimize and improve the efficiency of the existing equipment and pipelines.

This is achieved by optimization of HABSHAN-5 NGL run-down system to achieve lower energy consumption and saving the investment of around 5 MMUSD.

Habshan 5 NGL shipping pumps 545-P-101 A/B/C/D have never been successfully commissioned despite several modifications and trials by the EPC contractor and pump OEM due to the inherent design problems. As a result, the pumps have been replaced with a similar new pump (designed with 8 impellers). However, and due to variable pressure at Bab manifold, it was proposed to provide pressure control valve by the CONTRACTOR at the run-down line.

It was studied and recommended to de-stage the pumps with 4 impellers (future: 6 impellers) from 6 impellers (future: 8 impellers) and utilizing the existing flow control valve to accommodate the excess head generated by the pump for various operating scenarios.
Integrated Surveillance in Cheleken Block Offshore Turkmenistan Using Automated Steady State and Transient Models
Authors: Espinoza Roberto , Mohan Uniyal Suraj , Marcelo Jaramillo Rivadeneira Ivan
Published: November 2017

This paper describes the workflow where wells and production network (15 platforms and 100 active wells located in the Cheleken Block offshore Turkmenistan) are automatically modeled daily in a steady state and transient tools to finally be analyzed in a web based surveillance system. Contributing in the daily well production surveillance, optimization and core field operational processes like flushing and pigging pipelines, dewaxing wells, etc.

The Cheleken Block Central Data Gathering System (CDGS) was fully integrated with steady state and transient models (wells and network). These models are updated and run automatically on daily basis from the CDGS.

The close monitoring of the frequent routing diversion of wells and flowlines, separators, flares, etc. was solved with the implementation of a workflow to automate the updating of these routing in the database and in the Field Network models, enabling proper rollup of production, feeding into the transient model and analyze results in a web based integrated surveillance tool.

The implemented tools and workflows improved production surveillance and analysis with the gained comprehensive insight into the operations through overall asset. Analysis and reporting of performance indicators including trends of actual production against plan, downtime analysis and other operational workflows in a reduced timeframe compared with conventional methods of analysis.

The implemented web based integrated surveillance tool provided a single way to integrate operations from a broad range of disciplines with cross domain workflows and integration with different software and systems. This integration, allowed to dramatically reduce the time of analysis of models results from weeks to hours. This was possible with the automation all manual tasks in a single environment.

This paper details the implementation of integrated field surveillance and modeling workflows which can be assessed on daily basis. This integration was implemented using open source concept allowing multiple engineering software and databases (from different vendors) to operate simultaneously
Pseudotransient Linear Flow in Naturally Fractured Reservoirs
Authors: Assiri Wisam J. , Ozkan Erdal
Published: November 2017

Most unconventional reservoirs are characterized by an ultra-tight matrix and commercial production requires existence of a pervasive fracture network surrounding hydraulically fractured horizontal wells. Production behavior of fractured horizontal wells in these reservoirs is usually associated with natural-fracture dominated linear flow, which is diagnosed by a ½-slope straight line on log-log coordinates. This paper shows that additional pseudotransient linear flow regimes are possible at late-intermediate times with the same conventional diagnostic features of linear flow. These flow regimes correspond to the physical conditions (i) where the flow in the matrix is pseudosteady while the natural fractures have transient flow or (ii) where the natural fractures experience boundary dominated flow concurrent with transient flow in the matrix. An analytical solution is provided with a suite of tools to analyze transient and pseudotransient linear flows. The solution is based on the trilinear model with a stimulated reservoir volume (SRV) idealized by the transient, dual-porosity slab assumption. The model is a proxy for some tight-oil plays, such as the Eagle Ford, Bakken, and Niobrara, where thin layers of fractured carbonates providing the flow capacity are interbedded by layers of tight shale or marl, which act as the storage medium. Asymptotic solutions are derived for linear and bilinear flow regimes and conditions for their existence and start and end times are provided. Simulated examples indicate that confusing pseudotransient linear flow with the conventional linear flow creates up to three orders of magnitude differences in the estimates of permeability, fracture half-lengths, or the size of the SRV. Application of the analysis is also demonstrated on real data from an unconventional well.
A Proven Multidisciplinary Approach in Combating Water Flow Potential While Drilling the Asmari Formation in the Western Region of Abu Dhabi
Authors: Khan F. A. , Alhanash M. , Walters G. , Elenbaas M.
Published: November 2017

Water influx from a shallow sandstone formation caused problems in the Western Region of Abu Dhabi. Four wells were drilled in one field and have consistently recorded water flow issues causing Non-Productive Time. This paper looks into the problems recorded in the Drilling Reports and End of Well Reports and provides a technical proposal to combat the problems.

The Asmari Formation is encountered in the 26" hole section and is normally cased off with 20" casing. The water influx problems which were in some instances combined with losses not only hampered the drilling operations but also resulted in poor cement jobs requiring remedial actions and challenging well abandonment.

The main objectives are; Drill the 26" hole section through the Asmari Formation and cement the 20" casing to surface with no water influx and no mud lossesCementing the 20" casing to surface and eliminate remedial cement jobs

The approach described in this paper to achieve the above mentioned objectives was derived from three technical drilling disciplines, Drilling Fluids System, Cement Slurry Design and Operational Practices.

The proposed approach was successfully applied to the recent well drilled in the field in 2016/2017. This is illustrated in the case study at the end of this paper which clearly shows that the objectives were fully met.
The Impact of Smart Completions on Optimal Well Trajectories
Authors: Maas T. R. , Bouts M. N. , Joosten G. J. , Jansen J. D.
Published: November 2017

When new wells are planned, typically the same trajectory is used for assessing the effectiveness of conventional wells and wells with smart completions. This study demonstrates that the economically optimized trajectory for smart and conventional wells can be very different. Two new well trajectory optimization algorithms were developed using Stochastic Pattern Search (SPS) principles. In both algorithms, random perturbations are made starting from an initial well trajectory, which are sent to a reservoir simulator. Thereafter the perturbation with the highest Net Present Value (NPV) is selected. New perturbations of the selected well trajectory are made and simulated to, again, select the highest NPV. This process is repeated until a certain stopping criterion is met. The two methods differ in the selection of the perturbations used to initiate the new iteration and have a slightly different computational performance. To demonstrate the difference between the optimal well trajectory of a well with a conventional and a smart completion, both the SPS1 and SPS2 method were evaluated using a realistic, but slightly simplified reservoir model. Both methods were able to optimize the trajectory for both conventional and smart completions. The SPS1 method quickly converged to a local optimum, whilst the SPS2 method was able to determine a trajectory with a significantly higher NPV for both the conventional and smart wells. Moreover, the optimal well trajectory with the smart completion, as found by the SPS2 algorithm, had an NPV that was 40% higher than the smart well with the trajectory which was optimal for the conventional completion. Following the above, it can be concluded that when smart completions are assessed, well trajectory (re)optimization can have a very significant value impact and may be crucial in evaluating the full potential of the completion. Furthermore, it was shown that, for the investigated case, the SPS2 procedure is a good method for well trajectory optimization in a three-dimensional reservoir and, although more testing is needed, it is believed that it has potential to work with any type of completion.
Unlocking the Hidden Potential of an Upper Jurassic Carbonate Reservoir After 46 Years of Field Discovery: A Case Study in Offshore Abu Dhabi
Authors: Maalouf Christophe Bassem , Hernandez Hernandez Jose , Zidan Maher , Uijttenhout Mattheus , Al-Jaberi Salem
Published: November 2017

After a long history of unsuccessful appraisal wells, a new phase of reservoir appraisal focusing on data gathering for reservoir and fluid characterization led to positive results. Fluid sampling, acid recipe, formation pressure, and horizontal drilling were key factors for the successful appraisal. This reservoir is now a significant upside for the field development plan.

During the early phase of field development, careful data gathering plan was designed to characterize the reservoir. The plan included coring, logging, reservoir formation pressure, downhole fluid analysis, fluid sampling, conventional Pressure, Volume, and Temperature (PVT) studies, and asphaltene and flow assurance studies. After collecting downhole oil samples, a compatibility study with acid recipe was performed and many chemical additives were tested to find the optimal one. A horizontal drain was drilled to maximize the reservoir contact. The well was tested with drill stem test (DST).

Reservoir formation pressure acquired in 4 pilot holes at locations covering the reservoir confirmed fluid mobility, initial reservoir pressure, and possible oil pool limits. Downhole fluid analysis and sampling allowed the characterization of the reservoir fluid properties. Conventional PVT, asphaltene and flow assurance studies confirmed light oil with good flow potential. However, the compatibility study with existing acid recipe showed a high increase in fluid viscosity. This could prevent the well from flowing after matrix acidization. Naphta, among many tested chemical additives, proved to be the best to resolve the viscosity increase. The horizontal drain was successfully acidized with the new acid recipe and the well flowed oil during DST for the first time, 46 years after the field discovery. The well was tested through separator at different chokes before the main pressure build-up (PBU). The well was shut-in for 78 hours. BU analysis showed that reservoir permeability is in line with previously collected cores.

Although earlier appraisals were successful in upper reservoirs, a classic approach to reservoir appraisal of this thin oil reservoir failed. Our approach of carefully planning the data gathering sequence, testing acid and oil compatibility, proved essential to understand the past failures, correct the shortcomings, and carry on a successful appraisal.
Appraising Unconventional Play Potential in Egypt's Western Desert
Authors: Salah Mohamed , Ibrahim Mazher H.
Published: November 2017

With the increase of Egypt's domestic demand for energy, economical production from unconventional reservoirs is a great challenge to maintain production's annual decline. This has spurred interest in the development of unconventional resources, such as tight reservoirs and shale gas, particularly because of the enormous success in North America that brought unconventional resources to the forefront of the discussion on the future of energy. The country has launched studies to evaluate, explore and appraise several prospects for unconventional gas in Shoushan-Matrouh and Abu Gharadig basins. Exploratory pilot data wells were drilled and completed in the appraisal program for collecting the required data to evaluate the reservoirs qualities, demonstrate the availability of reserves, and identify optimal technology to maximize productivity and set the foundation for future development of these unconventional plays. Logs, core testing, and analysis service data were performed on or collected from these wells. Laboratory testing was conducted to understand the complex mineralogy and variable rock fabric. Geomechanical rock properties derived from advanced petrophysical analysis of newly acquired high-definition triple-combo full-wave sonic logs and core samples were combined to develop sophisticated models. These understandings helped reduce uncertainty and the lessons learned from this work and presented in this paper helped define completion and stimulation technologies for horizontal wells.

This objective of this paper is to review of the results and share lessons learned related to the recent appraising activities of unconventional plays in Egypt's western desert, evaluate these unconventional resources to unlock their potential. In addition, this paper present the challenges of development, highlight the best strategies required for field development to capitalize on the promising potential of these reservoirs through an integrated advanced workflow. The results from this study will shed light on the results of recent unconventional gas exploration and appraisal activities, which indicate that the western desert of Egypt holds substantial resources of unconventional gas. This unconventional gas can help to change the slope of production rates in the country positively and set the foundation for future development of these plays.
Determination of Fluid Connectivity in the Middle Marrat of the Jurassic Fields of North Kuwait using Oil Fingerprinting
Authors: Dekker R. , Tegelaar E. , Perrotta S. , Miller S. D. , Le Varlet X. , Hasler C-A. , Narhari S. R. , Rao J. D. , Neog N. , Dwindt A. A. , Al-Haidar S. , Dashti Qusem
Published: November 2017

The primary objective of the present study is to determine the fluid connectivity in the Middle Marrat of the major Jurassic fields in North Kuwait. Understanding fluid connectivity on both geological and production time scales has a direct impact on static and dynamic reservoir modeling, history matching, fluid property variations during production and zonal allocation of comingled production.

123 light oils and condensates were analysed using multi-dimensional gas chromatography (MDGC). The resulting so-called fluid fingerprints were interpreted in the context of a complex geological framework resulting from extensive sedimentological, petrographic, and structural geology studies. A detailed description of different fluid families allowed reconstruction of reservoir connectivity on a geological time scale. Fault transmissibility was reconstructed from the distribution of fluid fingerprints of samples taken during well tests or/and early production representing the fingerprint of the initial fluids in place. Also, the significance and extent of baffles to vertical fluid flow like anhydrites or low permeability streaks could be evaluated.

In time-lapse-geochemistry, fluid fingerprints are monitored during production. Changes in fluid fingerprints were interpreted in terms of fluid movement from other reservoirs along fault systems. These changes in fluid fingerprints matched the changes in fluid properties observed during the well testing. In other examples, changing relative contribution of different separate flow zones that are commingled in the subsurface were recognized.

The results are used to update/constrain the 3D static & dynamic models. Results help to understand connectivity, fluid flow and Pore Pressure Prediction (PPP) for new wells to be drilled.
Coupled Multi-Reservoir Multi-Network Production Optimization of an Onshore Middle-Eastern Reservoir with Sour Gas Reinjection for Miscible EOR
Authors: Pathak Varun , Palaschak Chelsea , Kumar Anjani , Eastick Rob , Schulz Ralf , Al-Hadhrami Abdullah
Published: November 2017

Integrated reservoir & production modelling can be extremely beneficial in conducting production forecasting for complex systems consisting of multiple reservoirs, fluid mixing, and complex production networks. These forecasts are even more valuable in scenarios such as sour gas separation, compression, and re-injection into multiple oil and gas reservoirs. The challenges in performing such work include modelling of the reservoir and fluid complexities while correctly representing the reservoir and production network, and optimizing the entire system together. Such tasks have been a daunting proposition for the petroleum industry because of the technical and logistical shortcomings in the traditional approach of integrated modelling where several tools are coupled together explicitly.

In this study, a new, fully-coupled implicit tool was used to model an onshore middle-Eastern asset with multiple reservoirs, each with unique fluid, and multiple networks. The asset uses complex fluid mixing in the integrated network, multi-stage separation followed by gas sweetening, compression and re-injection of compressed sour gas into the reservoirs. A multi-fidelity approach was used throughout the modelling workflow, incorporating reservoir and production related uncertainty in the forecast and optimization process. For example, some reservoirs were modelled with refined numerical discretized models, some with upscaled numerical discretized models and some with decline curves. A total of 16 reservoirs linked to a single production system were modelled as an integrated system. Unique compositional fluid models were used for each discretized reservoir, as the reservoirs had distinct fluid phase behavior during primary production and under miscible enhanced oil recovery.

Consequently, an integrated system was built that contained numerical discretized and decline curve reservoirs, fluid complexities, high fidelity wells, and a production network with gas separation, sweetening and re-injection. The oil production and recycled gas injection were optimized using rules and long-term forecasts were generated.

Throughout the work, several production and reservoir engineers collaborated and shared data on the single multi-user, multi-disciplinary tool using a relational database – which solved the logistical challenges associated with modelling such large-scale projects where the use of traditional methods can often lead to communication breakdowns and data discontinuities.
Repeatability of a Highly Stable Permanent Seismic Source Evaluated Through Long-Term Operation at the Aquistore CO2 Injection Site
Authors: Nakatsukasa M. , Ban H. , Kato A. , Worth K. , White D. J.
Published: November 2017

Time-lapse seismic is often used for reservoir monitoring. Although some case studies have been reported, especially for offshore oil fields, similar onshore Abu Dhabi studies have been limited. Onshore monitoring challenges are mainly due to hard carbonate reservoir rock, in which fluid displacement invokes only minor changes in rock properties. Moreover, complex near-surface structures create strong surface-related noises such as surface waves and elastic scattering. These noises significantly degrade the repeatability if repeat data are recorded with positioning error of 1 meter. To address the problems above, permanent reservoir monitoring has been spotlighted recently. Although permanent receivers are widely used for seismology, few studies of permanent seismic sources have been reported. In this study, we demonstrate a permanent source, Accurately Controlled Rotational Operated Signal System (ACROSS), which has a fixed position and excites highly repeatable seismic waves by rotating an accurately controlled eccentric mass. We deployed ACROSS at the Aquistore CCS test field onshore in Canada and recorded the wavefield with permanent receivers buried underground. The ACROSS system was operated several times throughout one year. The data acquired in a continuous 45 day operation were analyzed to calculate variation of amplitudes. The result indicated that we had obtained very stable waveforms with less than 3% variation if the data is stacked sufficiently. We also compared the two datasets acquired at different times of the year by calculating the normalized root mean square (NRMS) as a repeatability index. The histogram showed that the peak of NRMS distribution approached ~15% with only front and back mute processing. These results support our conclusion that an ACROSS system has potential to be used for reservoir monitoring in onshore fields by providing highly repeatable data for an extended time period.