bluuebunny/crossref_metadata_2025 huggingface dataset:
ROP Enhancement in High Mud Weight Applications Using Rotary Percussion Drilling
Authors: Li Bodong , Aljohar Abdulwahab , Zhan Guodong David , Sehsah Ossama , Otaibi Ali , Suo Zhongwei
Published: November 2020

This paper introduces the implementation of hydro-efflux hammer as an effective rate of penetration (ROP) enhancement tool. In the test well, the target formations are mainly composed of dolomite, limestone and carbonate with hard and abrasive characteristics. In addition, the carvings caused by the unstable shale formation in the upper section result in an increased mud weight, and associated drilling difficulties and low penetration rate. The conventional drilling techniques including mud motor have not been effective in this scenario. By implementing a 9-inch hydro-efflux hammer to drilling across the given formations, a significant ROP enhancement was observed. The deployment was planned based on quantitative analysis of formation characteristics, a study on the correlation between the tool's performance parameters and formation anti-drillability parameters, and the well design. The rotary percussion drilling parameters, bottomhole assembly (BHA) and bit selection are optimized through impact resistance and bit aggressiveness analysis. The result showed an ROP enhancement of over 47% compared with the offset average, providing an effective alternative for similar applications.
How to Meet Operational Challenges in An Extreme VUCA Environment by Adaptive Process Control
Authors: Igave Abhijit Uttam
Published: November 2020

The energy industry has been hit hard by current global economic interruptions: rapid drops in demand, a changing mix of preferred products, plummeting crude prices, difficulty staffing essential production sites and fragile supply lines. The profound challenges facing the Oil & Gas and Refining sector have never been more evident than during the COVID19 crisis. The chemicals and refining markets are very competitive, volatile and fast paced. To maintain a strong market position, companies need to look harder and deeper into their equipment, production and operations to ensure the production chain is optimized. Industry is finding out ways on how Adapt to significant changes in operating points for your process units under this VUCA (Volatile-Uncertainty-Complexity-Ambiguity) Environment. "There is no question that we are in a VUCA environment,".

Under current "VUCA Environment", Oil & Gas, Refining Industry across the globe are facing below challenges,

Significant changes to product demand necessitate turndowns & ramp-ups to be managed safely Workforce shifting to remote and essential-only due to pandemic risk Margin optimization more critical than ever Specific energy reduction still a key objective Need for agility with product mix changes Need for sustainability of APC applications benefits

The synergy between innovations in APC model identification, automated testing, quick and easy APC retuning and controller operating modes are creating opportunities to bring new efficiencies to the process of sustaining APC controllers under this extreme VUCA environments.

Latest Innovations in the Advanced Process Control are helping Industries to maintain the Advanced Control benefits at the maximum.

State-of-the-art Adaptive Process Control solution to enable non-disruptive testing in the background to build & adapt controller models to new operating conditions Safely manage turndowns & ramp-ups via background testing & model updates. Optimize control while testing. Quickly adjust controller tuning to align with changing market conditions to be more Cost efficient and less energy consumer as operation strategy easily. Improve operating margins across enterprise with greater visibility into APC benefits and performance via Centralized Performance Monitoring. Agility as APC dynamics are automatically adjusted via variable time constants under APC Controller. Remotely monitor performance with secure data access
Integrating Drilling Dynamics into Automated Geosteering
Authors: Pare Andrew , Ferro Ardanuy Aida , Engle Caleb , Genco Andrew , Crookston Glenna , Gee Timothee , Maus Stefan
Published: November 2020

Developing resources in congested fields requires precise drilling to keep the wellbore in the correct stratigraphic unit and avoid collisions with existing wellbores. Automated geosteering is an advantageous method because it eliminates subjective and lengthy manual interpretation. We present an algorithm that incorporates drilling dynamics data to estimate rock strength, correlates to nearby offset wells, and locates the drill bit in stratigraphy. This new method is faster and more objective than the traditional manual interpretation.

During well planning, gamma ray intensity, sonic, and geologic logs from nearby wells are recovered and used to calculate the Confined Compressive Strength (CCS) of the stratigraphic column using empirical and physical formulas. While drilling, the algorithm receives gamma ray intensity and drilling dynamics data (e.g. weight on bit, rate of penetration, revolutions per minute, fluid flow, and differential pressure) from the subject well and calculates the Mechanical Specific Energy (MSE) of the penetrated rock. Finally, the real time MSE and gamma from the subject well are correlated automatically with the previously generated CCS and gamma logs of the offset wells to locate the drill bit in stratigraphy.

This approach to automated geosteering was tested on a large database of subject wells and offset wells from multiple basins in North America. We find that the nearby CCS logs generated from sonic data are significantly correlated with MSE values from drilling dynamics data from the subject wellbore. CCS and MSE values can therefore be used as complementary rock strength parameters for each stratigraphic unit. Furthermore, the automated geosteering algorithm has been successful in estimating the drill bit position in the stratigraphic column during real-time drilling simulations of incoming drilling dynamics data. Incorporating rock strength estimation and matching is a complementary and valuable technique to the standard gamma log interpretation for steering a wellbore to a geologic target. The automated algorithm facilitates the simultaneous correlation, in conjunction with gamma ray intensity, against multiple offset wells.

Traditionally, geosteering is accomplished by manual comparison of LWD (Logging While Drilling) gamma ray intensity with nearby gamma logs from existing offset wells. Our approach is a significant advancement because it incorporates gamma ray data and previously unused drilling dynamics data, while automating the geosteering removes laborious and subjective processes. Mature oil fields contain considerable information on rock strength and our automated geosteering algorithm makes optimal use of this information to improve wellbore positioning.
Single and Multi-Well Synthetic Well Log Generation using Multivariate Analysis
Authors: Alimohammadi Hamzeh , Mahmoudi Saman , Chen Shengnan
Published: November 2020

With the rapid development in machine learning (ML) and deep learning (DL) algorithms, computations power and availability of the massive amount of data, ML and DL approaches have gained a lot of interest in oil and gas industry and brought the data science and analytics into the forefront of this industry. Using traditional neural networks (NNs) to normalize log and generate synthetic well logs is not a new idea. However, the recent advancement in ML and DL methods encourages to further research and revisit the prediction power, discuss the methodological limits and further improve the approach and prediction algorithms in single and multi-well synthetic well log generation for reservoir characterization and formation evaluation.

In this study a data-driven procedure was implemented based on deep neural networks for density generation using multivariate inputs of well log data. The density prediction was formulated as a depth series regression problem where multiple inputs including different open hole logs are used as the input of a reverse model that estimates density. Different recurrent DL structures including Long Short Term Memory, Gated Recurrent Units, and Bidirectional Recurrent Neural Networks were tested in this study to select the most time-efficient and high performance model for density log generation.

The models were fed with different number of available curves to explore a relationship and potential predictive power of several variables on the target curve (density) to eliminate unnecessary and irrelevant curves and end up with a model that uses a few curves to generate the target curve. Training datasets consist of real well log data of 25 wells logged offshore Middle East. Different metrics (RMSE, MAE, and R2) were used to compare the performance of the models and stacked LSTM of three layers showed the highest performance. Using this approach companies could cut costs by generating high quality synthetic data with a faster turnaround and without the need of relogging.
Production of Methane Rocket Propellant on Mars
Authors: Al Kaissi Talal , Al Shehhi Abdulla , Marpu Prashanth Reddy , Gee Martin
Published: November 2020

Space exploration has made significant advances over recent years. There are now many planned robotic exploration missions for the Moon, Mars and asteroids. Carrying enough fuel for future return journeys, particularly as necessary for human exploration missions poses a key challenge, or inefficiency of having to take all required fuel for return trip for the mission, incurring significant weight penalties and opportunity cost. The UAE has announced its Mars 2117 Vision, a 100 year plan, to build a habitable settlement on Mars, and in particular: "Mars 2117aims to build the knowledge and scientific capabilities that will enable the UAE to realise humankind's universal dream of the very first sustainable settlement on the red planet within the next 100 years".

Recent exploration of Mars has identified some key in-situ raw materials regarding the presence of water ice, and an atmosphere for which the major component is carbon dioxide, comprising approx. 96%. The UAE's current Emirates Mars Mission "Hope" aims to build on that knowledge and increase our understanding with respect to the Martian climate. Future missions to Mars will lead to the development of in-situ resources. The associated technologies share many synergies with terrestrial activities concerning oil, gas and the energy industries. Furthermore, it is considered that the technology development for off-world resources may have significant advantages for terrestrial industry. The associated innovations and philosophy are consistent with the UAE's National Objectives regarding the furthering of a "Sustainable Environment and Infrastructure".
Digital BOPE Testing – A Case Study Leading to Improved Technical Assurance While Reducing Time Requirements and Cost in Onshore Drilling Operations
Authors: Anderson Mark , Halloran Sean , Hoke Gabriel , Skinner Les
Published: November 2020

A digital blowout prevention equipment (BOPE) pressure testing system was deployed on a remote land drilling rig in Argentina in October 2017 to replace the older testing method using an analog circular chart recorder. This paper presents a case study of that deployment, focusing on change management, cost savings, and overall BOPE testing improvement.

Results from the deployment include a 50% reduction in BOPE test time with subsequent savings that amount to 6 times the cost of the digital test equipment, improved safety, improved efficiency in addressing problems that would result in a failed test, improved data reliability, and repeatability in subsequent BOPE pressure tests.
Supply Chain Powered by AI and Blockchain
Authors: Batra Mayur , Manchanda Naresh , Moskalev Andrei , Uttamchandani Rohini
Published: November 2020

It is a common knowledge that the main goal of companies is to supply goods and services to buyers at maximum price for minimum cost. For companies such as energy producers, with complex and dynamic supply chains, this often causes cost control issues. Previously, business models based on VI (Vertical Integration) or outsourcing could mitigate cost increases, but these models have limits. A new paradigm is proposed: use of distributed ledger technology in the form of a blockchain-based supply chain integration solution. By permitting participants in a supply chain to integrate information flows in a secure, quick and automated levels of efficiency that are achieved and cannot be reached by other technologies and do not require participants to change their IT platforms.

The main purpose for the creation and management of the "supply chain" is for the seller to provide the buyer the maximum value – whether of a product or service – at the lowest cost. Here is a depiction of the "links" in the general supply chain for energy production.
Designing Drilling Fluids Advisory System
Authors: Al-Yam Abdullah Saleh , Wagle Vikrant B , Al-Rubaii Mohammed Murif , Abubacker Ziaudeen
Published: November 2020

Suitable drilling fluid with suitable properties is a critical factor in successful drilling and completion operations. Drilling fluids consultant will need information such as formation lithology, wellbore geometry, temperature, pressure to be able to formulate fluids for different sections. Drilling fluids consultants' job is to aid drilling engineers and scientists to formulate effective drilling fluids systems for the entire well sections.

The paper describes a drilling fluid advisory system with demonstrating examples to the end user. The advisory system includes a Bayesian decision network (BDN) model that utilize inputs such as temperature and pressure and provide drilling fluids formulations based on Bayesian probability determinations.

A number of drilling fluid specialists/experts feedback were gathered to develop the drilling fluid advisory system. The drilling fluid specialists/experts feedback were used to design Bayesian Network Model that would allow the end-user to take an elementary data set to obtain optimum recommendations in the area of drilling fluids.
Corrosion Resistant Alloys Test Protocol Development and Results for an Ultra Sour Reservoir Containing Elemental Sulphur
Authors: Andres Bogdan , Mizukami Akio , Pimenta Gervasio
Published: November 2020

Corrosion of Oil Country Tubular Goods (OCTG) is a traditional concern in the Oil and Gas industry, as it represents a major component of well integrity management. Various corrosion mechanisms may affect the performance of materials in downhole applications, especially in corrosive environments containing large amounts of H2S, CO2, and Chlorides. In high sour environments, elemental Sulphur may also be present, in which case, it will act as a strong oxidizer, affecting the performance of the material selected.

In this paper, a test methodology was developed to selected a technoeconomical fit for purpose material for application in the development of a Ultra Sour Reservoir Containing Elemental Sulphur. This methodology consisted in evaluation of the SCC (Stress Corrosion Cracking) behaviour of Corrosion Resistant Alloys (CRA) of group 4D, as per ISO15156-3/ NACE MR0175-3, at the border between 4D and 4E environmental limits including the simultaneous presence of dissolved and elemental Sulphur in the fluid.

A testing set-up was developed to ensure the contact of elemental S with the material in order to ensure the strong oxidizing reaction at the surface of the material.

The behavior of the materials was assessed by Slow Strain rate testing (SSRT), C-Ring Sulphide stress cracking and Crevice corrosion test, conducted on UNS N06985. Grades sourced from three (3) distinct manufacturers were tested to evaluate different manufacturing systems (routes) and levels of cold work, which are known to be critical in the performace of the cold worked CRA materials.

Although, CRAs have a greater CAPEX due to the content of costly chemical elements: Chromium, Nickel, Molybdenum, etc, they may be cost effective in a life cycle cost analysis as they will prevent workovers, assure a higher HSE and well integrity level.
The Use of Novel Technology of Inflow Chemical Tracers in Continuous Production Surveillance of Horizontal Wells
Authors: Chaplygin Dmitry , Azamatov Marat , Khamadaliev Damir , Yashnev Viktor , Novikov Igor , Drobot Albina , Buyanov Anton , Ovchinnikov Kirill , Husein Nadir
Published: November 2020

The paper describes the use of new generation of inflow chemical tracer application at Salym Petroleum Development Upper-Salym oilfield as a part of Smart Field project. This kind of well surveying using indicators that allow the evaluation of the inflow composition for each hydraulic fracturing port in horizontal wells remotely, without any additional risky and costly downhole activities.

The new inflow chemical tracer technology is based on the use of nano-particle quantum dots, which give a level of high accuracy in quantitative analysis of fluid inflow. Markers, which are micromillimeter in size, are inserted into the polymer coating of the proppant. The technology involves the injection of marked polymer-coated proppant in the process of MHF (multi-stage hydraulic fracturing). Once the MHF is done, and the well is producing, the fluid samples are taken at surface and tested in a laboratory using machine learning software. Once the obtained data is interpreted, a flow profile of oil and water can be generated for each frac stage.

One of the main advantages of marker technologies is that they provide data over a long period of time, with a significant reduction in operating cost. It opens the door for new opportunities in terms of more accurate reservoir characterization and better hydrocarbon recovery. The key element of the technology is the use of specialized intelligent machine-learning software based on Random Forest algorithm to produce production flow profile.

The described methodology was used during the multi-stage hydraulic fracturing operation on oil wells 8105 and 8064 of Upper-Salym field. The volume of proppant injection at each stage was 20 tons, out of which 15 tons were of marked proppant containing a unique code for each stage. As soon as marked proppant has a contact with well fluid markers are emitted into fluid and sampling at the wellhead can be done any time when information required. The results of samples analysis are reports with graph showing quantitative distribution of water and oil production of each fracturing interval.

The new generation of inflow markers allows for continuous production, surveillance and quantitative analysis of oil and water phase from each fracturing stage. This enables better decision making to optimize the production and make better decisions for water conformance interventions. This surveillance method does not require complex and risky well interventions or production shutdowns, making it substantially more cost effective than the existing conventional methods.

Optimization of oil production, remote monitoring for risks minimization, reduction of operating costs - all these are the results of the introduction of Smart Fields technology systems in the Salym group of oilfields.
How Technology Can Support in Tackling Drivers' Fatigue: Case of Petroleum Development Oman
Authors: Hadzic Demir , Al Esry Hamed , Marsh David
Published: November 2020

Petroleum Development Oman (PDO) operates in harsh environment with more than 320 million km-driven annually. Driver fatigue is one of the leading causes of Motor vehicle Incidents (MVI) within PDO operations. The objective of this research was to try and further understand how technology can support in the prevention of driver fatigue. A further objective was to explore driver beliefs related to fatigue as well as fatigue technology, which could help them in identifying fatigue in themselves and preventing further undesirable events. After the technology was applied, it was discovered that driver fatigue occurred at least once in every three journeys, whereas driver distraction occurred more than 4 times in a single journey. The initial survey showed an average level that drivers believed that the technology could prevent fatigue and further crashes. The experience conducting this research using technology greatly helped PDO HSE team to understand driver fatigue, and to develop preventative mechanisms to tackle driver fatigue.

The first chapter contains a review of the literature related to both technology and fatigue, including theory and definitions to help the reader to understand them better.

The second chapter discuss the research methodology, as well as the aim and research questions. It also includes a description of the technology, describing the system modules and their purposes.

The third chapter discusses the main data and results along with lessons learned.

Finally, the conclusion includes a discussion relating to the benefits of using technology to manage driver fatigue as well as recommendation for future enhancements.
Enhancement of Well Deliverability and Scrutinize the Proppant Discretion Based on Net Present Value
Authors: Sial Amaar , Memon Asim , Baig Abdul Ghaffar , Nawab Sohail
Published: November 2020

The selection of proppants is quite a challenging task as the cost almost comprises 20% to well over 50% of total fracturing jobs when ceramic is used. So, in the current situation of oil price crises, optimizing the proppant cost in Pakistan, where fracturing cost is twice as compared to the United States of America, not only provide better-optimized stimulation but also maximizes the Net Present Value. The objective of this study constitutes of two: firstly, to investigate the various types of proppants for peerless fracture parameters based on the post-frac results by using the FracCade simulator. Secondly, to evaluate the Net Present Value and select the most effective proppant based on the Net Present Value.

In this case study, the research is conducted on scrutinization of proppant discretion based on net present value, the reservoir data under the study is real-time data of x-well of Tobra formation. The average permeability of the formation is 1md. The focus of this project is to investigate the effects and potential of 25 proppants on hydraulic fracturing treatment. Prior to the selection of the proppants for the evaluation of NPV, sensitivity analysis is done based on closure stress and fracture parameters to screen out 20 proppants. The final selection of proppant is made on the Net Present Value (NPV) which will decide which proppant will give the economic edge to the fracturing treatment.

The result of the study is based on the investigation of 25 proppants based on the Net Present Value (NPV) of the fracturing treatment. Before the selection of the proppants for the evaluation of NPV. Almost 20 proppants have been screened out based on the closure stress and fracture parameters. Finally, 5 proppants after technical scrutinization are selected for the evaluation of NPV. From 17 proppants, 5 proppants are selected based on fracture conductivity. These are selected for the evaluation of NPV. Among the 25 proppants, proppant which gives the highest Net Present Value (NPV) is Sintered Bauxite which enhances the well productivity up to 3.5 times and gives the Net Present Value (NPV) of $12,548,762.98.
Enhanced Produced Water Deoiling Using a Centrifugal Separator
Authors: White Ramsey , Mulas Simone , Al-Jughayman Ahmed
Published: November 2020

Objectives/Scope

A field trial was conducted for deoiling produced water at a Saudi Aramco GOSP. The objective of the field trial was to prove the concept of the centrifugal separator and test its capabilities to deoil produced water at varying feed rates and inlet concentrations.

Methods, Procedures, Process

The centrifuge was fed from the common water outlet line of a gravity water oil separator. Samples were taken for oil-in-water measurement using ASTMD7678. The testing covered various flowrates and inlet concentrations, which were adjusted by manipulating upstream conditions. Several parameters were used to determine the adequacy:

Outlet oil-in water content (expected significantly less than 50 mg/l) and sufficiently high separation efficiencies to achieve the specification Unit downtime due to trip and failure of the unit and due to filter/screen cleaning and replacement

Results, Observations, Conclusions

The feed rate was adjusted by manipulating a valve at the inlet of the separator. A sample at the inlet and outlet of the separator was taken at each flowrate and condition as per the test guideline. It was noticed that inlet oil-in-water concentrations to separator were mostly on-spec, with only a few of them above 100 mg/l, as a result of temporarily lowering the dehydrator interface level for the the trial.

The following observations can be made based on the test run data:

The outlet oil-in water met the spec, far exceeding expectations Oil in water removal efficiency varied significantly, varying from 65-90% depending on rate and inlet concentration There were no issues in terms of unit downtime related to trips and filter/screen plugging

Novel/Additive Information

This was the first trial for a Saudi Aramco field. The process was applied to a facility with tight emulsions and a challenging environment that requires a highly efficient deoiling process, which the centrifugal separation has proven to be. Potential applications for produced water treatment and waste water handling can be derived from the field trial result.
Risk Mitigation Strategy Improves Drilling Performance of Shale Gas Horizontal Wells
Authors: Zhang Jinwu , Hua Jiqing , Xiong Xiaolin , Liu Jinxia , Li Mingbo , Gui Feng , Ghosh Amitava , Ong See Hong , Huang Xingning , Deng Lichuan
Published: November 2020

The shale revolution has extended the life cycle of the oil and gas industry, promoted the growth of global oil and gas reserves and production, and changed the energy's strategic pattern of various countries. At present, the national shale-gas demonstration area of PetroChina Changning and Weiyuan is in the stage of large-scale production. Horizontal well and hydraulic fracturing are two key technology that have proven to provide an effective way to economically develop medium to high maturity shale gas resources. However, due to geological complexity of the shale-gas demonstration area, and the lack of robust analysis and research on overpressure mechanism and wellbore instability characteristics, drilling events such as stuck pipes, lost circulations and inflows occurred frequently during horizontal well drilling. These non-productive events greatly restricts the wellbore construction cycle time and the production of shale gas reservoir. A comprehensive geomechanical study was carried out from which the three pressure profiles required for drilling, i.e., pore pressure, collapse pressure and fracture gradient, are established. The study also clarified the spatial distribution of overpressure across the field. The improved pore pressure and geomechanical understanding of the field provides the necessary inputs for an integrated, multi-disciplinary approach carried out during pre-drilled analyses, real-time monitoring and post-drilled evaluation to manage the stability of horizontal wells. The safe mud weight window derived from geomechanics provides the basis for mud weight and mud formulation designs that can be continuously optimized to improve wellbore stability and reduce drilling risks. The integrated approach has been applied for 4 horizontal wells in Weiyuan's shale gas field. One of the wells, Wei202-H34-3, has the horizontal section length of 2500m, making it the longest horizontal section recorded in the block. Drilling performance analyses of the well showed that the overall drilling risk, the wellbore construction time, and the drilling costs were substantially reduced by optimizing the drilling operations through geomechanics integrations and applications. The experience and knowledge obtained from this integrated workflow will provide guidance and serve as reference for the efficient development of unconventional oil and gas reservoirs in China.
Water Reactive Alloys with Artificial Intelligence, Smart Plugs Formulation for the Middle East and North Africa
Authors: Roy Ting , Shenoy Ram , Markel Daniel , Bolze Victor , Wilkinson Christian , Roy Indranil
Published: November 2020

Technology gaps to harness source rock or shale, unconventional reservoirs in the Middle East and North Africa pose unique challenges. Carbonate reservoirs, supplying Ca2+ ions resulting in passivation of traditional magnesium-based water reactive alloy alloys and abundance of H2S/CO2 rich production fluids at high pressure high temperature downhole conditions cause unpredictable degradation of plugs. This leads to the technology gap, an economical prediction mechanism to assess the degree of dissolution for deployed tools, which has prevented rapid uptake of water reactive alloys in these markets. Here we present, materials and methods to design and manufacture water reactive (fully dissolvable) alloy plugs for multi-stage stimulation (MSS) AKA hydraulic fracturing for the Middle East and North Africa (MENA). The backbone of our water reactive plug is a self-articulating amorphous and bulk nanocrystalline alloy and/or partially or fully vitrified dissolvable material with artificial intelligence (AI), sensing in its DNA, with an ability to learn from the environment it is deployed in. Additionally, these materials will deploy articles that relay information from downhole to surface without conventional telemetry. Other embodiments of the technology building blocks encompass novel, multi-layered smart water reactive nano-materials, further enhancing tailored and timed dissolution.
Application of Petroleum Geochemistry as a Surveillance Tool for Assessment of Annulus Seepage in Offshore Abu Dhabi, UAE
Authors: Koksalan Tamer , Ahsan Syed Asif , Azouq Youcef , Alhouqani Shamsa Sulaiman , Al Blooshi Ahmad , Ali Basioni Mahmoud
Published: November 2020

Oil leakage, due to well integrity issues of varying proportions, from downhole completions is a common phenomenon despite all measures and adherence to regulations. These leakages potentially could cause environmental damage through surface spill, aquifer contamination and in worst-case scenario loss of human lives. In an offshore setting, impact of well integrity issue can be more severe than in an onshore well due to complex and often costly offshore well operations. Downhole completions including cement quality deterioration occurs with the passage of time due primarily to corrosive nature of hydrocarbons produced from a well. Oil companies perform routine well integrity surveillance by acquiring real time annulus pressure data, cement bond, temperature and sonic logs to assess well integrity and perform remedial measures, if and when, required. Leakage may also occur in a complex pattern from nearby wells and different reservoir than the suspected reservoir and show up in the annulus or eventually on the surface. Whilst, well integrity surveillance data indicates leakage when it occurs, finding the exact source location of leakage is often difficult. Objective of this study was to perform a cost-optimized reservoir to annulus leakage oil correlation using geochemical methods in an offshore well to establish the source of oil in the annulus.
Lessons Learned from Extensive Well Testing Operations in Khuff Formations Offshore Abu Dhabi
Authors: Hollaender Florian , Basioni Mahmoud , Al Blooshi Ahmed Yahya , Elmahdi Ahmed , Sayed Sohdy , Belova Natela , Menon Pradeep , Azoug Youcef
Published: November 2020

Sanctioning the development of complex carbonate reservoirs and selecting an adequate development plan is not a trivial matter. Understanding formation heterogeneities such as layering, lateral continuity, natural fracture networks, or the impact of faulting are crucial to identify the optimal development strategy. Furthermore, completions strategies can have an outsized impact on the viability of such projects.

Those challenges are particularly acute in the Khuff formations offshore Abu Dhabi and detailed formation evaluation is required.

An extensive appraisal campaign was performed in Khuff reservoirs, with multiple appraisal wells drilled in different fields. Those wells were evaluated using detailed logging campaigns and then subjected to well tests, usually through drillstem testing (DST) for targeted intervals. Depending on the openhole logs, one to four tests were performed on each well.

Multiple objective had to be met: assess formation potential, tie petrophysical properties to inflow sources observed from production logs, perform descriptive pressure transient analysis to understand formation structure away from the wellbore, and assess the optimal completion and stimulation strategy.

The interpretation of well tests, combined with advanced petrophysical analysis, formation test data, and production logs, provided a unique insight into the nature of the Khuff reservoirs. A wide range of responses was observed, from tight to highly productive, but not necessarily with clear prior indications of deliverability or inflow intervals.

Clear evidence of natural fracture networks or thin highly productive zones were observed, not necessarily correlated to standard logging results. By contrast, other tests yielded more of a matrix-driven flow, even though marked by significant vertical variations. Lateral continuity was also shown to be a possible development challenge, with behavior changing significantly between wells in relative vicinity of each other.

This paper will present the observations but also offer some explanations and highlight remaining questions stemming from the analysis of the data acquired. Critically, this will show how the near-wellbore formation characteristics cannot readily yield a clear picture of larger-scale formation behavior and that only actual well testing combined with an appropriate stimulation strategy can unlock formation potential.

Observations from the appraisal data over the wide number of wells considered in this study brought a unique insight into the characteristics of the Khuff reservoirs, offshore Abu Dhabi. We highlight their complexity and identify challenges in reliably characterizing them to enable optimal development. This study also shows how well test results can uniquely provide answers not obtainable through other means.
West Africa Salt-Zone Cementing Best Practices: Laboratory Evaluation and 5-Year Field Application Review
Authors: Nana Degaul , Uba Christopher , Johnson Carl , Lonca Matthieu , Zghal Jamel
Published: November 2020

To determine which salt-based cement system [potassium chloride (KCl) or sodium chloride (NaCl)] was suitable for cementing across halite and anhydrite salt sections in West Africa, eight slurry recipes were tested to assess how formation salt contamination would affect slurry properties. The formation salt used for testing was sampled from a deepwater, presalt well in Angola. The recommendations developed from the laboratory study were implemented in 10 projects across West Africa over 5 years with 100% operational and well integrity success.

A candidate deepwater well was selected in which the surface and intermediate strings penetrated salt formations. A total of four slurry designs (a lead and tail slurry used on each casing string) was programmed. Each slurry was designed and tested as two distinct systems using KCl and NaCl salt respectively, yielding a total of eight slurry designs. Using the methodology and data presented by Martins et al. at the 2002 IADC/SPE Drilling Conference (SPE-74500-MS), the mass of dissolved formation salt that each slurry may receive during placement was estimated and duly incorporated into each slurry design. Subsequently, the salt-contaminated slurries were tested and compared with the properties of the initial uncontaminated slurries. Based on these results, conclusions were then made on which salt slurry system (KCl or NaCl) exhibited better liquid and set properties after contamination with formation salt. Subsequently, this knowledge was applied to 10 projects across three countries in West Africa.

This study showed that when the contact time of liquid cement slurry to salt formation was low—typically when the salt formation interval across which the cement slurry flowed was less than 100 m thick—the level of formation salt dissolution entering the slurry during placement was limited. In this case, a KCl salt-based slurry delivered improved liquid and set properties as compared with a NaCl salt-based slurry. In the field, this knowledge was applied in all oilfield projects cemented by an oilfield service company between 2015 and 2020. This included deepwater, shallow offshore, and onshore wells. All related salt-zone cement jobs, including sidetrack plugs, placed across the salt formations were successful on the first attempt.

In an absence of industry consensus around salt-formation cement slurry design, this paper validates a guideline for West Africa, based on results from laboratory testing and 5 years of field application. In contrast to current literature that recommends only NaCl salt-based slurry designs across halite or anhydrite salt intervals, this work demonstrates that KCl salt-based slurry systems can effectively be used to achieve well integrity where a halite or anhydrite salt interval is less than 100 m [328.1 ft] thick.
Modelling of Micro-Sized Graded Proppant Injection in the Natural Fractures Around a Hydraulic Fracture with Consideration of Proppant embedment and Deformation
Authors: Liu Huifeng , Li Jiaxue , Yuan Zebo , Liu Jv , Ren Dengfeng , Feng Jueyong , Lv Yongke
Published: November 2020

Natural fractures are usually developed in unconventional reservoirs like shale, tight sandstone, CBM etc. Volume fracturing has been extensively used in such reservoirs to create a complex fracture network to provide flow paths for oil and gas. However, the stimulated area is usually very limited because conventional proppants cannot percolate into deep reservoirs. Micro-sized proppants have been introduced in recent years to increase the size of stimulation area, but the modelling of the injection of micro-sized proppants is far from good.

The most representative model for micro-proppant injection is the graded proppant injection model proposed by Khanna, Keshavarz, et al. They have done a lot of work of establishing the analytical models and performing experiments to verify their models. The highlight of their work is finding the optimal proppant packing ratio. However, the biggest shortcoming of their models is that proppant deformation and the embedment of proppants into the fracture wall are neglected. Besides, how to establish an optimal injection schedule using the optimal proppant packing ratio is not clear.

In this paper, an analytical model of calculating proppant deformation and embedment is introduced. It is incorporated into the graded proppant placement model to investigate the influences. Since proppant deformation and embedment will cause the reduction of natural fracture aperture, fracture conductivity instead of fracture permeability is employed to evaluate the influences of graded proppant placement. A diagram based on conductivity for determining the optimal proppant packing ratio is drawn and compared with the Khanna's diagram. Most importantly, an optimal pumping schedule for stimulating the natural fractures or cleats around a hydraulic fracture is established, and the influences of proppant deformation and embedment on it are studied.

The results show that with consideration of proppant deformation and embedment, the fracture conductivity is reduced considerably and the optimal proppant packing ratio is significantly larger. The time-fixed pumping schedule and the concentration-fixed schedule are all different when proppant deformation and embedment are considered: the particle concentration is higher and the pumping interval is longer. This paper improves the previous graded micro-sized proppant injection model and the calculating results are better. The method of establishing optimal pumping schedule provides a direct guidance for researchers and onsite engineers.
Geomechanical Evidences for Conjugate Slip and Block Rotation Along the Strike
Authors: Noufal Abdelwahab
Published: November 2020

Wrench fault system is the predominant regime of Abu Dhabi tectonics and their related damage zones influences the stresses between the fault segments and hence representing the main controlling factors in field development of hydrocarbon.

The strike-slip structures are related to the activation of sinistral strike-slip shear zones oriented N75°W, which initially inherited in the Arabian Plate craton and activated trough the geologic time. The main reactivation happened with the Late Jurassic- Middle Cretaceous and then by the Paleocene and finally by Late Miocene. These reactivations accompanied with block rotation of the stress tensors from NE-SW to NW-SE and finally by NE-SW respectively. The identification of transpressive and transtensional structures are the main concept of locating the hydrocarbon provinces.

During the transpressive stage, sinistral transcurrent movements along the Abu Dhabi Shear Zones led to the activation of a multiple set of parallel sinistral faults, conjugate and antithetic to the master fault. The activation of these structures determined a deformation by block rotation that provoked an overall anticlockwise rotation of (N150° to N120°) of 30°.

The data show how the rotations occurred might be caused by the activation of multiple strike-slip fault sets and that the rotational mechanism around vertical axes is connected to transpressive tectonics. The use of kinematic and geomechanical models allow quantification of the blocks rotation due to the combined action of multiple sets of strike-slip faults with modest displacements and to demonstrate that the rotation of blocks and their lateral movement constitute two different, contemporaneous expressions of a single deformational event. A systematic classification of the rotational zones and their influences on reservoir behavior was addressed.

Classification of stressed zones favoring reactivation based on their location relative to fault segments growth. Therefore, development of structures were combined with fluid flow in/between fault segments to characterize placing wells for an effective field development plan.
Modeling Approach and Non-Uniqueness of Polymer Coreflood History Match and Field-Scale Forecasts
Authors: Al-Rawahi Hamza , Delshad Mojdeh , Sepehrnoori Kamy , Al-Kindy Abdullah
Published: November 2020

This work investigates the implications of propagating the uncertainty and non-uniqueness of fitting experimental data into the forecast of field implementation of polymer flooding. This research sets the foundation for developing a general framework for modelling and probabilistic performance forecast of chemical flooding.

History-matching of polymer coreflood results is posed as a bi-level optimization problem that solves for true waterflood residual oil saturation (Sorw,∞) in the upper level and the relative permeability curves (exponents and endpoints of Corey function) and polymer adsorption parameters in the lower level under two different physical interpretations of the difference between remaining oil saturation after waterflood (Sorw) and that after polymer flood (Sorp): Displacement Efficiency Interpretation(Sorp ≥ Sorw,∞) solely attributes the significant difference between Sorw and Sorp to improved displacement efficiency.Viscous Fingering Interpretation (Sorp ≤ Sorw,∞) considers viscous fingering during waterflood.

A range of Sorw,∞ values has been identified for each model based on satisfying cut-off error criteria. For each Sorw,∞ value, dependent parameters are obtained and used in a simplified forecast of field performance in a quarter-five spot well pattern. The inverse of the error within acceptable range was used as probability density function (pdf) for Sorw,∞ which, combined with forecast results, enabled calculating P10, P50, and P90 of Sorw,∞, recovery factor, and economic metric (i.e. cumulative discounted revenue).

The probabilistic forecast results show that the viscous fingering interpretation is more reliable as it generates a forecast with less uncertainty. The impact of model selection and non-uniqueness of fitting lab data on the quantified uncertainty associated with field forecast is demonstrated and the premise of developing a bi-level optimization framework for modeling and probabilistic forecast of chemical flooding processes is supported by the findings of the study.

In this work a novel iterative tangents construction technique that considers the inter-dependence between retardation factor due to adsorption and polymer shock saturation is used along with a mechanistic form of fractional flow curves that includes shear-thinning and effective viscous fingering effects. The analytical solution was verified against fine-grid simulation and the two solutions were nearly identical while the former is several orders of magnitude faster enabling extensive investigation of the range of parameters that match the coreflood results and forecast uncertainty under different technical and economic considerations.
High-Performance Electrostatic Coalescer – A Novel Technology for Improving the Economics of Oil-Water Separation
Authors: Ismail A. S. , Menchaca A. E. , Balk W.. , Akdim M. R. , Less S.. , Oshinowo L..
Published: November 2020

Crude oil dehydration is one of the first, most important and challenging steps in oil production and processing. To achieve rapid and energy-optimized demulsification of water-in-oil emulsions, Saudi Aramco and TechnipFMC have jointly developed a high performance electrostatic coalescence technology. This paper discusses the performance test results of this technology.

Physical separation of emulsified water from produced crude oil is challenging due to the small water droplets, presence of surfactants covering the water droplets that inhibit the otherwise natural coalescence process, as well as the high viscosity of the continuous phase and the narrow density difference between oil and water in the mixture. Conventional mechanical and thermal methods are proven for viscosity reduction and efficient separation, but they also require high capital expenditure and large footprint. Deploying conventional electrostatic coalescers for demulsification proves to be uneconomic at remote locations. Chemical methods, namely the injection of chemical demulsifiers to dissolve the above mentioned surfactants, is expensive and makes the production process highly dependent on the supply of such chemicals, which can be affected by geo-economical as well as environmental circumstances.

In this paper the performance results from tests conducted jointly between TechnipFMC and Saudi Aramco using the compact high performance electrostatic coalescer (HPEC) technology are presented. The HPEC was tested successfully on an Arab Medium crude oil under different process conditions, including different temperatures, electric field strengths, and two geometrical configurations of the electrostatic cell internal features. The study results demonstrate the rapidity and effectiveness of the HPEC in destabilizing Arab Medium crude oil emulsions.