bluuebunny/crossref_metadata_2025 huggingface dataset:
Development and Testing of an LWD Ultrasonic Microimaging Tool: Field Test Results from the Middle East and Europe
Authors: Warot Gregory , Wallace Shawn , Mostafa Hassan , Elabsy Eslam , Di Tommaso Davide , Abdelkarim Aly , Ciuperca Constantin-Laurian
Published: November 2018

Increased development of naturally and hydraulically fractured unconventional reservoirs from horizontal wells, drilled with oil-based muds, has created a need for high-resolution logging-while-drilling (LWD) borehole imaging tools capable of resolving fractures in this borehole environment. A new LWD ultrasonic borehole imager has been developed and tested to meet this need.

Borrowing from wireline ultrasonic imaging technology, a 250 kHz piezo-electric transducer was adapted to an LWD drill collar. The single transducer serves as both transmitter and receiver: transmitting an ultrasonic pulse, and measuring both the amplitude and two-way travel time of the acoustic reflection from the borehole wall. The LWD tool takes advantage of drill string rotation making a 360-degree scan of the borehole with a single fixed transducer. Finite element modeling and laboratory testing in artificial formations and a large limestone block were used to determine the spatial resolution of the image, as well as the sensitivity to downhole acquisition variables such as standoff, tool eccentricity, and mud attenuation. Prototype tools were then field tested in several horizontal wells to verify the functionality and image resolution under actual drilling conditions.

The borehole images from horizontal wells in unconventional and conventional reservoirs in the Middle East and the UK verified that tool responded as designed. These images, recorded in both oil-based and water based muds, revealed open and cemented natural fractures, drilling induced fractures and borehole breakout, fine-scale bedding, and other textural geological features such as vugs and stylolites. A variety of drilling-related borehole artifacts were also observed, including keyseats, stabilizer impressions in the borehole wall, tool marks from a rotary steerable tool, and gouges made by the bit rotating off bottom. The amplitude image proved more sensitive to fractures, bedding, and other geological features, while the travel time image, combined with input mud compressional velocity, provided a 360-degree borehole caliper image, showing the borehole size and shape.

Although high-resolution LWD electrical imagers have been available for years, these can only operate in conductive, water-based, muds. As most horizontal wells in both conventional and unconventional reservoirs are now drilled with oil-based muds, the development of a high-resolution ultrasonic imager capable of identifying natural and hydraulic fractures, fine-scale bedding, secondary porosity, and other small scale features in wells drilled with oil-based muds fills an important gap in LWD technology.
A Successful 4D Seismic Monitoring in Middle-East Carbonate Reservoir Context
Authors: Cailly F. , Al-Romani T. , Hubans C. , Lafram A. , Al Kaabi A.
Published: November 2018

This paper describes 4D interpretation results in a very challenging Middle East carbonate context.

It consists of a 4D pilot (OBC/OBC) over a giant field divided into two phases. For Phase1 the monitor seismic survey has repeated the geometry of the base survey (parallel shooting) to get started in the best possible 4D conditions. For Phase2 the monitor seismic survey design is a modern source spread acquisition for wide azimuth objective. It is clearly different from the base survey design, and so starts with a worse 4D repeatibility.

In this paper, we describe the challenges attached to both phases of this pilot and explain how in the end it has been successfully interpreted.

A focused study is made on a particular 4D anomaly corresponding to an increase of impedance in the reservoir. This is interpreted as the water front movement (due to water injection) during the interval between base and monitor surveys. Petrophysically this is consistent, if water replaces oil in the reservoir then impedance increases. However, 4D interpretation can be ambiguous and other production phenomena can explain impedance increase, so the interpretation must be assessed carefully. This is done through calibration of the interpretation to well data (time evolution of the water cut).

The final interpretation is robust. Other elements not described in the paper could have been added to consolidate the interpretation like the fact that interpreted 4D anomalies (and so water rise-up) stop vertically on a well known impermeable barrier (anhydrite level).

Once the 4D signal is calibrated, unexpected phenomena (i.e. heterogeneities not predicted by the reservoir model) are highlighted as potentially providing added value to reservoir understanding. As a deliverable, 4D anomalies are interpreted as 3D geobodies and a water rise-up top surface is picked. This information will be key to position new wells and to update the reservoir model.

Though 4D seismic techniques are very mature and widely illustrated in clastic reservoir environments, it is still rarely used operationally to monitor carbonate fields. This paper proves the concept that a reliable 4D signal can be extracted over such Middle-East carbonate reservoir.
Relaunch of the IOGP Recommended Practice for Safety in Lifting and Hoisting Operations 2018
Authors: Lawrie Graeme
Published: November 2018

Objectives/Scope: IOGP first published a recommended practice for lifting and hoisting operations in 2006. However, it is clear that lifting and hoisting incidents are still occurring in our industry, so IOGP established an industry task force representing a cross section of operators and service companies to improve and revise the RP to take account of lessons learned over the last 12 years. The Paper will describe the lessons learned and the enhancements to the document.

The Paper will identify through a series of case studies how lifting and hoisting accidents are still occurring and what steps can now be taken to help close these shortcomings.

Methods, Procedures, Process: The Task Force brought together a good cross section of subject matter experts in our industry representing both offshore and onshore activities. The TF met regularly to review fatal accident causes and high potential near miss events to identify deficiencies in the original guidance and to seek to enhance our understanding and knowledge.

Results, Observations, Conclusions: The result is a significant revision to the existing recommended practice. Specific areas for improvement; subsea lifting and dynamic lifting operations (marine conditions). It also looks at best practice associated with lifting over or near live plant. Updated lifting plans, definitions and safety technology.

Novel/Additive Information: The RP is free to all people to download and use, it is not limited to IOGP members. The RP contains many helpful tools that can be implemented at all levels within our industry.
Reduce Emissions and Save Energy by Converting Flared Gases into Fuel Gases
Authors: Bakthavachsalam Venugopal , Abdul Shathar Sevideen
Published: November 2018

Energy management and fuel conservation are crucial for controlling emissions and enhancing profitability of today’s oil and gas industries. Many organization are pursuing flaring and emission reduction initiative as part of their energy management system thereby minimizing operating cost and liberation of harmful greenhouse gases to the environment.

This paper presents a flaring and emission reduction initiative implemented at ADNOC Gas Processing natural gas liquids (NGL) fractionation plants in Ruwais. The design limitations on spent gas piping system leading to loss of valuable of fuel gas resources were recovered by enhancing the capability of the system.

Following is the list of actions completed to implement the initiative:Feasibility study for utilization of flared spent regeneration gases as fuel gases for boilersUpgradation of spent gas piping for sour serviceApplying an innovative non-linear fuel blending controller

The successful implementation of the initiative by in-house team resulted in an impressive flaring reduction of 60% and a reduction of CO2 emissions of 62,700 Tons/annum.
The Concept of Right Modelling, Toward a More Effective Usage of the Static Modelling Tool
Authors: Lazar Raffik
Published: November 2018

The reservoir modelling task occupies most of the reservoir modeller daily routine. The key challenge faced by the reservoir modeller has shifted from the ability to build A reservoir model to building THE right reservoir model. The concept of right modelling responds to the challenge of building more predictive reservoir model by using a structured methodology to use the static modelling tool in a more efficient fashion. Complexities are introduced in the model only when required and supported by hard data. A set of guidelines, covering the overall workflow, are established for the principal reservoir modelling tasks. By following the guidelines, the reservoir modeller can handpick the best modelling strategy to ensure that the reservoir is modelled at the right level. Following the right modelling concept minimizes the risks of under modelling (not tackling the technical need in a robust way) or over modelling (losing the technical relevance by being too narrow) the reservoir.
Reservoir Management Solutions Through Innovative Seismic Modeling
Authors: Goraya Yassar , Al-Neaimi Ahmed Khalifa , Al-Felasi Ali , Van Kleef Franciscus Johannes , Al-Dhafari Bader , Akram Fazeel , Ashraf Muhammad , Khemissa Hocine
Published: November 2018

Objectives/Scope

Today, the major challenge in reservoir monitoring is difficulty of building high-resolution reservoir model. Reservoir modeling can only be truly effective in increasing oil and gas recovery and providing input to recovery programs if it is able to incorporate 3D problems with innovative techniques of structural characterization,synthesizing seismic attributes, well information and Seismic Inversion.

Fit for purpose seismic PSDM processing, advanced level seismic attributes generation,seismic inversion, high quality sonic and density log acquisition and correction was the main objective to integrate petrophysics, rock physics, facies classification and geophysics.

Case studies supported, how an integrated novel approach could be useful to determine the relationship between seismic structural and reservoir characterization attributes and reservoir properties to improve the reservoir management.
Debottlenecking of an LNG Plant to Capture Gas with Higher Nitrogen Content
Authors: Halil Kirpici Onur , Salmeen Abdulla Haitham , Abdulkareim Al-Ameiry Ahmed , Kuntadi Agung Margono , Kumar Das Anjan
Published: November 2018

Liquefied Natural Gas (LNG) has been a significant contributor to the global energy market. This is emphasized with continuous demand from industrial and population growth. ADNOC LNG has stepped up efforts to enhance its asset reliability and utilize every opportunity with utmost attention to HSE, bolstering its role as a key gas operating company. ADNOC LNG runs 3 facilities, in which three operating trains are LNG producers.

Over several years, the company has conducted tests and studies with assistance of global engineering service companies and vendors. The rationale was envisaged in 2011 to check for possibilities of debottlenecking LNG Train-3. The aim of the conducted studies was to exceed the design LNG production capacities of 384 ton/hr and 390 ton/hr in summer and winter respectively. The study objective was to establish the limit for production rate considering all operating parameters at post 2009 overhaul, bottleneck process findings, Integrity & Reliability issues and safety elements. The scope of this two phase study was detailed in a "Management of Change" approval for process plants for the purposes of this paper, in which the next auxiliaries’ adequacy step based its analysis.

Following a structured process (study, classify, prioritize, debottleneck, test, assess); the conducted studies surfaced a number constraints that limited LNG production. Recommendations were implemented to surpass the identified constraints. In short, this entailed minor modifications including replacement of 2 valves for better controllability, 1 set of PSV’s and structural reinforcement/monitoring.

Ultimately in 2015, ADNOC LNG achieved a new rated Train-3 LNG production capacity of 394 ton/hr and 408 ton/hr in summer and winter respectively. This gain of 10 ton/hr has yielded additional returns and the accomplishment has paved the way for safe increased production with a satisfactory margin to operate within.
How is the Dynamic of Drillstring Going Under Internal & External Countercurrent-Axial Flows?
Authors: Liu Yongsheng , Gao Deli , Tan Leichuan , Li He , Cai Zhixiang
Published: November 2018

A dynamic model of drillstring under internal and external countercurrent-axial flows is presented, and the stability of drillstring under different drilling parameters is analyzed. Results are compared to previously published simplified models (e.g., fluid-free models, influx models, outflow models). The dynamic governing partial differential equation (PDE) of drillstring is established under internal and external countercurrent-axial flows by means of the differential element method. The equation taking into account the mechanical force, the fluid pressure, the buoyancy force, the inertial force, the gyroscopic force, and the Coriolis force. PDE equation can be converted into the ODE equations by using the Differential quadrature method (DQM) and combining the boundary conditions under different working situation of drillstring. The vibration response to submerged drillstring under different parameter αc, which represents the annular clearance, is studied by plotting the stability diagram. The results were compared with the reference model established by the former researcher. Two cases, cantilever beam model and hinged-hinged boundary conditions, were discussed and found that increases the value of αc that means the annular gap increases, the outflow velocity should be decreasing, thus the effect of fluid induced vibration would be decreasing. As for cantilever case, the stability region will change obviously with the change of parameter αc, but for Hinged-Hinged case, parameter αc has little influence on the stability region. The novelty of the new dynamic model of drillstring is lying in considering the internal and external countercurrent-axial flows effect for the first time. The numerical results can be implemented in drilling engineering to predict drillstring vibration and guide drillstring design.
Innovative Geophysical Hazard Survey for Jack-Up Rig Approach and Operating in Hazardous Area of Shallow Seabed Due to Gas Pockets or Entrapped Gas and Tower Integrity Update and Conclusion. A Case Study
Authors: Goraya Yassar , Nair Rajeev Nair , AL-Neaimi Ahmed Khalifa , AL-Felasi Ali , Kleef Franciscus Johannes , Al-Dhafari Bader , El-Sayed Mohamed Abdul-Khalek , Akram Fazeel , AL-Hosani Ibrahim Ali
Published: November 2018

During a routine tower maintenance visit, gas bubbles were observed at sea bed. The challenge now was to identify the source of the gas leak and identify areas where gas had accumulated. The observed gas seep, escaped from the seabed to the water column and was in the vicinity of the TWR-2 platform as confirmed during a diving survey. A geophysical survey was initiated to understand if gas had accumulated in the subsurface and whether it was safe to approach the site with a rig to kill the well.
A Comprehensive Reservoir Quality Characterization for Fractured Basements in India
Authors: Hati Samhita , Chawla Hemlata , Ghosh Arnab , Guru Udit , Ray B. B. , Guru Rakesh , Pattanaik Sambit
Published: November 2018

As oil and gas exploration and development forays into unconventional plays, more specifically, basement exploration, its characterization and understanding have become very important. The present study aims at understanding the reservoir quality in terms of complex mineralogy and lithology variations, porosity, fracture properties and distribution near and away from the borehole using an integrated approach with the help of elemental spectroscopy, borehole acoustic imager, borehole micro-resistivity imager, nuclear magnetic resonance and borehole acoustic reflection survey.

A comprehensive petrophysical characterization of different mineralo-facies of basement was carried out using elemental spectroscopy, formation micro-resistivity imager, borehole acoustic imager and combinable magnetic resonance along with basic open-hole data. Two distinct rock groups were identified – silica rich, iron poor zones having open fractures with good fracture density, porosity and aperture and silica poor, iron rich zones with no open fractures, poor fracture density, porosity and apertures. The zones with open fractures were the prime zones identified for further testing and completion. However, the near well bore analysis could not explain the oil flow from one zone having open fractures, whereas another similar zone showed no flow.

Borehole Acoustic Reflection Survey processing was attempted to understand how extent of fractures beyond the borehole wall contributed to productivity from a well. The presence of laterally continuous fracture network at an interval that coincides with the depths from which the well is flowing, in turn validated from production log data, explained fluid flow from basement. Furthermore, the absence of such network can cause no flow even though near well-bore possible open fractures are present.

Present study established the fact that, identification of potential open fractured zones in basement is a lead for reservoir zone delineation, however, a lateral extent of such basement reservoir facies is the key for successful basement hydrocarbon exploration.
Force Balance Analysis and Efficient Measures to Improve Vertical Sweep Efficiency in Oil-Wet Carbonate Reservoirs
Authors: Namba Takao , Nakashima Toshinori , Yonebayashi Hideharu , Hiraiwa Takeshi
Published: November 2018

Many carbonate reservoirs in Middle East under water or gas injection exhibit poor or limited vertical sweep efficiency due to channeling of the injected fluid through high permeability streaks (high-k streaks) and/or gravity segregation. In this paper, causes of the limited sweep efficiency and its possible mitigation measures are discussed through conceptual reservoir simulation and the force balance (FB) analyses of their results. The analyses are based on convention-diffusion-gravity (CDG) formulation, and applied to five-spot waterflood, line drive waterflood and line drive gas flood schemes to provide insights to improve reservoir development strategy.

In waterflood either in five-spot or line drive scheme, the injected water moves fast in a high-k streak in oil-wet reservoirs where the effect of convection decreases rapidly and the diffusion has no or limited contribution to diverting the water from the high-k streak to neighboring layers, leading to early water breakthrough and poor sweep efficiency. Gravity force works to slump the water into the high-k streak, thus accelerates water breakthrough especially in case the high-k streak is located at the bottom of the reservoir. For such reservoirs, the practical mitigation strategy will be to delay the decline of the convection effect. Mobility control is the effective mitigation measure in this regard. In-depth conformance control is another mitigation measure in line with this strategy. If the blocking is implemented sufficiently away from the wellbore and with sufficient blockage width, it can make similar level of positive impact on waterflood performance as that expected by mobility control with minimal impairment of injectivity.

In gas flood under unfavorable mobility ratio, gravity override is the key risk even in homogeneous reservoirs. Gas breakthrough is further accelerated in case the high-k streak is located in the upper part of the reservoir. In such reservoirs, the principal mitigation strategy will be to reduce the relative effect of gravity force in addition to increasing the gas front saturation. Enhancement of the viscosity of the injectant will realize both, thus lead to significant improvement of vertical sweep and oil recovery. On the other hand, in-depth conformance control will have positive but limited impact on gas flood performances.

Considering the study results mentioned above and the state-of-the-art of the related technologies, mobility control is considered to be the principal solutions to the poor vertical sweep both for waterflood and gas flood, and in-depth conformance control can be another cost effective solution for waterflood in the oil-wet carbonate reservoirs associated with high-k streaks.
Neutral Grounding of Dissimilar Generators in Offshore Power Systems
Authors: Pragasam Sathishkumar
Published: November 2018

Designing neutral grounding systems for Generators require careful consideration of various aspects, which are mainly related to the Generators themselves and, also with respect to other aspects of the overall system design. More importantly, when the Generators to be operated in parallel have dissimilar design, the neutral grounding design must address a whole array of issues and technical requirements. While there are solutions to mitigate these issues, some of them are not appropriate for offshore installations.
When Water Turns to Oil: Low Resistivity Pay Characterization through Integrated Open-Hole/Cased-Hole Log Interpretation
Authors: Raimondi Cominesi Nicola , Guglielmelli Andrea , Rotelli Fabiana , Putignano Natale , Roscini Paolo , Pirrone Marco , Galli Giuseppe , Vinci Fabio , Rametta Dario , Raniolo Stefano
Published: November 2018

Zubair is a giant oil field located in the South of Iraq. The production started in 1951 and current oil production is around 450 kbopd achieved through 150 wells completed in two main formations: Mishrif (carbonate) and 3rd Pay (sandstone). The scope of this paper is to show how an integrated methodology based on core analysis, open-hole and cased-hole logs unlocked the underneath potential of a sand layer (L1) with an anomalous resistivity.

Multiple wells, indeed, show resistivity curves in the L1 interval with surprising low values with respect to the average of other levels of the same sandstone reservoir. Therefore, fit-for-purpose open-hole (OH) and cased-hole (CH) log acquisitions have been integrated with information from cores and dynamic data (i.e. production logging) in order to better understand the phenomena behind the low resistivity scenario. As a consequence, several perforation extensions have been performed with L1 as the main target, providing an overall improvement of hydrocarbon deliverability without any increase in water production.

In details, routine and special core analyses in L1 samples delineate the typical setting of a fine-grained low resistivity pay sandstone, able to host a large quantity of irreducible water. However, such behavior is not always present among L1 cores. Therefore, a methodology aimed at characterizing this sandstone behavior was mandatory. Nuclear magnetic resonance logging, commonly used to identify low resistivity pays, was not a suitable option due to bad-hole problems. Hence, an approach based on a detailed integration of OH resistivity and CH pulsed neutron logging (PNL) is used to recognize and characterize such low resistivity pay. This method mainly relies on the fact that formation water is very conductive and strongly affects the resistivity, while its effects on PNL measurements are not so pronounced. Such intuition is confirmed by multi-rate PLT interpretations that dynamically describe the L1 sandstone with fair productivity index and high reservoir pressure, together with a significant dry production contribution. In conclusion, a clear geological trend of L1 resistivity behavior is revealed and associated to the decreasing cementation of the matrix and its coarsening in the same direction.

The integrated OH/CH methodology allows characterizing low resistivity intervals as pay zones. Such achievement represents an important milestone for the perforation strategy of new and existing wells in Zubair. As a natural consequence, the overall field production has been enhanced by widely applying the new technique without any increase in water-cut.
A Holistic Approach Utilizing Simple, Reliable and Cost-Effective Axial Friction Reduction System in Improving the Drilling Efficiency and Cost Optimization in the Directional Sections
Authors: Abdelhaq Zeina , Fei Ji , Wu Jiandong , Yan Miao , Yufeng Chen
Published: November 2018

The introduction and standardization of the use of an axial friction reduction tool by a service company in they Halfaya field for a national oil company has resulted in a significant improvement in drilling efficiency and reduction in operating costs.

The directional application in the Halfaya field in the start of the campaign was challenging for the operator and directional companies. Challenges in terms of high torque, poor tool face control resulting in multiple trips, damaged bottomhole assembly (BHA), and the inability to reach planned total depth (TD) forced the operator to call for alternative high-end technologies. Those technologies, although wellperforming, presented various operational challenges and did not represent a cost-effective solution to the operator.

The introduction of a simple axial friction reduction tool combined with a positive displacement motor assembly showed an immediate and clear improvement to the torque and drag issues and was comparable to the higher end alternative technologies that were not cost effective.

This paper presents how this tool became an essential part of the BHA with an average of 30% improvement on the overall performance. Apart from enhanced drilling efficiency, another major factor contributing to this achievement was at least a 50% reduction in the number of trips required to change the BHA components, resulting in a highly cost-efficient solution. This technology was successful across all well designs.

A holistic and optimization-based approach focusing on tool placement using a special algorithm was conducted in the field for both the buildup and the lateral sections. The performance of the tool was consistent and gradually improved to becoming the standard with motor assemblies completing sections in one run.

By introducing the axial friction reduction tool, there has been more than 100 runs to date over the course of the Halfaya field development that have lead to a massive cost saving for the operator.
Reservoir Management Through Characterization of Smart Fields Using Capacitance-Resistance Models
Authors: Salehian Mohammad , Temizel Cenk , Gok Ihsan Murat , Cinar Murat , Alklih Mohammad Y.
Published: November 2018

Use of smart well technologies to improve the recovery has caught significant attention in the oil industry in the last decade. Capacitance-Resistance (CRM) methodology is a robust data-driven technique for reservoir surveillance. Reservoir sweep is a crucial part of efficient recovery, especially where significant investment is done by means of installation of smart wells that feature inflow control valves (ICVs) that are remotely controllable. However, as it is a relatively newer concept, effective use of this new technology has been a challenge. In this study, the objective is to present the efficient use of ICVs in intelligent fields through the integrated use of capacitance-resistance modeling and smart wells with ICVs.

A standard realistic SPE reservoir simulation model of a waterflooding process is used in this study where the smart well ICVs are controlled with conditional statements called procedures in a fully commercial full-physics numerical reservoir simulator. The simulation data is utilized to build the CRM model to obtain the inter-well connectivities at the zonal level beyond only the inter-well connectivity data as smart wells provide control and information on the amount of injection into each layer or zone. Thus, after analyzing the CRM model to detect the inter-well connectivities at the zone/layer-level in an iterative way, the optimum injection not only at the well level but also at the perf/zone level is found. The workflow is outlined as well as the improvements in the results.

The smart well technology has been challenged with the associated cost component thus, it is important to present the benefits of this technology with applications in more diverse cases with different workflows. It has been observed that a robust reservoir characterization in an intelligent field can provide an insight into the physics of reservoir including smart wells with ICVs. The results are presented in a comparative way against the base case to illustrate the incremental value of the use of ICVs along with key performance indicators. Most importantly, it has been shown that smart well use without a robust reservoir management strategy does not always lead to successful results.

In reservoir management, it is not only important to catch the well level details but also see the big picture at the field level to improve the performance of the reservoirs beyond individual well performances taking into account the interference between wells. This method takes the reservoir surveillance to the next level where reservoir characterization is improved using smart field technologies and capacitance-resistance modeling as a robust cost-effective data-driven method.
A Review of Industry-Wide Advanced Completion Best Practices
Authors: Al-Rabeh M. N. , Al-Noaimi K. R. , Brown J.
Published: November 2018

The objective of this paper is to communicate operational and engineering process enhancement and cost saving initiatives in advanced well completions. The initiatives were identified following a detailed review of industrywide advanced completion best practices standardized over the past decade. Several operational and engineering best practices involving inflow control valves (ICVs), inflow control devices (ICDs), zonal isolation (mechanical and swell packers), multistage fracturing (MSF) and sand control technologies were examined. In addition, downhole pressure relief requirements were also considered to introduce new ways of enhancing well integrity by preventing casing corrosion.

A standard research and development methodology was utilized for this review. The methodology was based on collecting and documenting industrywide actual operational and engineering challenges in advanced well completion deployments for both oil and gas fields. These challenges resulted in either lost time at the rig site, necessitated workovers, or rigless operations. Examples of such challenges include extreme frictional forces during ICD deployments, repetitive solids removal practices prior to running ICVs, coiled tubing milling requirements for MSF, wash pipe deployments for downhole sand screen circulation, and calcium carbonate scale deposition in sand screens. The research also encompass a literature review for identifying further advanced completion challenges across the industry.

The review resulted in identifying several areas of potential improvement. As a result, multiple engineering and operational process enhancement initiatives were recommended. This includes the utilization of centralizers to reduce frictional forces in ICD deployments. Also, the application of isolation valves to eliminate wash pipe requirements in screens or ICDs. Moreover, running downhole annular relief check valves to preserve tubular integrity by eliminating casing-to-casing annular (CCA) pressure communication and utilization of mono-bore ball seat technology to eliminate milling in MSF. Finally, the utilization of sacrificial completion accessories to improve ICV cleanup practices and save rig time in addition to several other relevant initiatives across the industry.

In summary, the paper provides a deep dive into several technical advanced completion challenges across the industry. Also, several new initiatives are proposed with the objective of achieving significant cost savings. It is intended for these initiatives to be adopted as new advanced completion best practices. Not only to yield significant cost savings, but also to supplement the existing best practices body of literature in the areas of ICVs, ICDs, zonal isolation, MSF, well integrity and sand control technology.
The Most Common Impacts of Drilling Dynamics and Environments on Log-While-Drilling Data: A Study from Abu Dhabi
Authors: Thakur Parmanand Dhermeshwar , Agnihotri Praveen , Deng Lichuan , Soliman Ahmed M. , Kieduppatum Piyanuch , Fernandes Warren
Published: November 2018

Logging-While-Drilling (LWD) has incorporated almost all wireline-equivalent technology with the added advantage of logging high-angle and horizontal wells with reduced rig time, critical for cost optimization efforts.

LWD measurements are affected by a rugged drilling environment, and logging interpretation with a wireline mindset leads to erroneous results. Identifying measurement artefacts from real formation information is critical for reliable log analysis.

This publication discusses the most common effects of drilling dynamics and environments on LWD logs that were observed during logging and drilling wells in cretaceous carbonate reservoirs in an Abu Dhabi onshore field.

Log data from more than one hundred wells are reviewed to identify several interesting effects due to bottom-hole-assembly (BHA) design, BHA driving mechanism (Rotary steerable system versus mud motor), tool eccentricity, well angle, mud properties, differential invasion, borehole condition, formation fluid properties and lithology. In a few instances, some of these effects occur simultaneously, complicating the log response. These phenomenons are discussed in detail with actual examples and compared to offset wells and response modellings.

The rugged logging environment and limited formation damage due to invasion provide a unique opportunity to obtain additional insight about reservoir behavior, especially when compared to wireline data in an offset well or in the same well. Pre-job planning and modelling can use these phenomena for getting additional information about dynamic reservoir behavior. This paper highlights a few such applications.

This paper explains the impact of a dynamic drilling environment on LWD measurements and serves as a ready reference to identify measurement artifacts from real formation information. It is helpful as a guidebook for log analysts, geologist, geo-steering engineers and other non-specialists to identify LWD measurement artefacts.
Successful Implementation of 15K Open Hole Multi Stage Fracturing Completion
Authors: Rodoplu Rasim Serdar , Tiss Amine , Adnan Asif Bin , Siham Ahmed M.
Published: November 2018

15K Open Hole Multi Stage Fracturing (OH MSF) completion was successfully implemented with the goal of hydrocarbon production at sustained rates from tight HPHT gas formation and to diversify technology portfolio to address similar challenges.

OH MSF completion technology has been globally proven successful in enhancing the well design, stimulation efficiency and production. As more wells are being drilled deeper, longer and in more challenging formations, the OH MSF technology also evolved resulting in introduction of a HPHT – 15K psi working pressure - MSF system. The technology had to overcome many challenges before it could be deployed. Pre-deployment stages of this technology have two main components;Standard tool design including material selection, NACE compatibility, dimensions, API standard compliance, testing, and prototypingCompletion construction design, installation challenges & force analysis

The candidate well was drilled horizontally to achieve enough formation contact in a tight HPHT formation. Wells with similar poor development have been seen to require upwards of current OH MSF completions reaching to their limits of 10K psi differential pressure downhole to successfully complete with proppant fracturing. Candidate well was planned to be trial tested with 15K OH MSF completion to solve the challenge of high breakdown pressures and to capitalize on the greater productivity of open hole completions across this tight HPHT formation.

The proppant fracturing operations resulted in the successful completion of five stages of proppant fracturing in this formation. A total of more than 1.2 million lbs of proppant was placed during hydraulic fracturing operations exceeding 10K differential pressure across the MSF completion. The well showed an excellent post frac flowback results exceeding expectations. Previous wellbore completion pressure limitations in many instances acted as a constraint to reach job objectives has been surmounted.

The implementation of 15K OH MSF completion system has helped pave the way to attend tighter formations in an efficient and cost effective manner. Engineering approach and design to develop this completion system and utilization in the right candidate confirmed the benefit of the completion for field development options. The implementation of this technology will improve and diversify the efforts in exploiting tight HPHT formations.
A Numerical Study of the Influence of Nonlinear Fluid Flow Mechanism on Dynamic Production in Tight Gas Reservoirs
Authors: Dong Jiaxin , Ran Qiquan , Peng Hui , Wang Zhiping , Xu Mengya , Wang Cong
Published: November 2018

The Fluid flow mechanism in unconventional reservoirs is much more complicated than that in conventional reservoirs mainly because of the co-existence of various sized micro-nano pores and natural / artificial fractures in the same reservoir. Due to the various flow patterns and seepage mechanism among different-sized media, and also among different production periods in the same medium, the dynamic production is influenced by both the spatial variable and time variable. The capacity of the tight gas reservoirs is also thus greatly influenced.

In this paper, numerical simulation is used to automatically identify the flow pattern according to the critical criteria of flow in different media, and to simulate the dynamic production process with kinetic equations. The simulation is mainly focused on the following characteristics shown in the production process of tight gas reservoirs: I) high-velocity nonlinear, quasi-linear and low-velocity nonlinear flow regimes; II) the slippage effect and diffusion effect under low porosity, low pressure and low permeability conditions; and III) start-up pressure gradient, desorption effect and other seepage mechanism.

The simulation results reveal that: a) as the start-up pressure gradient increases, the production gradually decreases; b) the higher the high-velocity non-Darcy coefficient, the lower the production; c) the production increases along with the slippage effect on conditions that the pore pressure remains unchanged; d) the free gas content and the cumulative production are inversely related to the content of adsorbed gas; e) the greater the diffusion coefficient, the higher the production; and g) the higher the Langmuir pressure, the lower the curvature of the adsorption isotherm curve and the higher the gas production

Based on the above analysis, a better understanding about the influence of the flow state and seepage mechanism on dynamic production and productivity is obtained, which will help optimizing the development method and improving the accuracy of gas well productivity forecasting.
An Applied Machine Learning Approach to Subsea Asset Inspection
Authors: Bertram Stephen James , Fan Yilun , Raffelt David , Michalak Pawel
Published: November 2018

Subsea infrastructure inspection campaigns are conducted on a fixed time schedule to ensure the integrity of offshore assets while guaranteeing compliance with government and other stakeholders’ legislation. These thorough assessments of subsea assets are achieved by acquiring and processing survey results alongside the relevant engineering data and environmental conditions.

The current approach is not ideal. The infrastructure operators would prefer to have more frequent, on-demand field visits and base the assessments on an up-to-date high resolution, precise asset model. Unfortunately, this has historically not been technically feasible. The underwater inspection vehicles moved relatively slow, the positioning accuracy was limited, and the underwater sensors’ accuracy and resolution was not comparable with those used in air.

This is not the case anymore. We now operate inspection vehicles traveling with speeds over six knots! We can control them remotely from the office-based command center. Next to the acoustic technology, the vehicles are additionally equipped with optic sensors, dynamically collecting point clouds, images and videos of unprecedented resolution. Gigabytes of data hits the vessel every few minutes. And that's where it used to end…

Processing and, so called, "Digital Twin" modelling from this data has traditionally been taking weeks for every day of inspection. In many cases it was simply not technically possible since the data files were prohibitively big. Data required subsampling, more data processors had to go offshore, asset operators had to wait longer.

Given the increasing capacity of satellite links, limitless potential of commoditized cloud computing and sophisticated Deep Learning algorithms, we are now able to move subsea asset management to the new era. Through one of their latest research & development programmes - Roames, Fugro has been able to revolutionize the traditional workflows using the state-of-the-art digital technology. The resultant product is a bespoke, web-based service that enables asset (initially pipelines) inspection data to be uploaded to the secure cloud environment, processed using Machine Learning, verified by experts on shore and visualized in an intuitive 4D web viewer. All delivered to the geographically spread stakeholders, operators and decision makers in near real time. This approach greatly reduces the cost of infrastructure management practices, lowers the risk exposure and contributes to extended life of the asset.

The Roames, Machine Learning based methodology was validated using a vast archive of survey data prior to testing the workflow on a live project. Detailed method statement and field results are presented in this paper.
Quality Control of 3D GeoCellular Models: Examples from UAE Carbonate Reservoirs
Authors: Gomes Jorge , Parra Humberto , Ghosh Dipankar
Published: November 2018

3D geocellular static models are the key input for fluid flow simulations with the main aim to predict the future reservoir performance for a particular recovery scheme. Since the predictability of the dynamic model depends on the quality of the geocellular model, it is imperative that the input data, the modelling workflow, methodologies and approaches are verified and validated prior to the sanction of the geocellular model. The objective of this paper is therefore to discuss the process of performing quality assurance and quality control (QA/QC) of 3D geocellular models exhibiting real field examples from the Middle East carbonate reservoirs.

3D static models are built using data from multiple sources, at different scales and with different degrees of uncertainty. The validation and reconciliation of all the data is of paramount importance. The procedure to build any geological model is very similar provided all the data is available. Some variations in the procedure are expected depending on the complexity of the phenomena to model, but must of the time workflows divert based on data quality and data availability. In this paper we discuss the use of key validation checks for each step of the modelling process taking into account the data quality and field maturity, namely for the 1)- structural framework modelling, 2)- facies modelling, 3)- porosity modelling, 4)- permeability modelling, 5)- rock type modelling, 6)- water saturation modelling, 7)- upscaling and 8)- uncertainty analysis. The use and validation of the applicability of secondary variables in the petrophysical modelling, such as acoustic impedance from seismic inversion, is also addressed.

From the analysis of multiple geocellular models, inconsistencies were detected at different stages of the modelling process, starting from the well surveying with implications to horizontal well positioning within the framework, to the modelling of facies and petrophysical properties, with inconsistencies on variogram model parameters. Also, the validation of the velocity modelling and time-depth conversion used for the structural framework was validated by comparing FWLs depths against spill points. Furthermore, the quality of the facies model could be verified against regional facies belt maps (similar variogram azimuths are expected) while the validation of the permeability scale-up at well level could be achieved by reconciling with well test kh data. These are just a few examples of the material discussed in this paper.

The novelty of the quality assurance process pertained to 3D geological models is the identification of appropriate metrics with key performance indicators for each step in the modelling workflow. At the end of the QA/QC process the models are ranked in quality and technical gaps identified for subsequent model improvement. Guidelines and best practices are also presented in this paper.
Business Process Improvement in ADNOC Gas Processing through Lean Kaizen Approach
Authors: Balbahaith Amal
Published: November 2018

In the past decade, the expansion of global market has significantly changed and has showed remarkable growth. This has also led to more challenges and competition like never seen before. The competition became tougher as the range and quality of goods and services available broadened. Hence to thrive in such cut-throat competition companies now need to focus on providing quality service and products at competitive prices. This distinctive change in the market also resulted in change in the approach; from a solely profit based approach to quality based approach. The word "kaizen" in japenese refers to improvement. kaizen lean in business philosophy refers to removal unuseful contents. It means to change for the better. In order to improve continuously and persistently all that is waste must be eradicated. The concept of lean and kaizen go against the traditional belief of just making improvement, amendments or addition to the existing system instead of time and again focusing on removing the waste and what is no longer required.