bluuebunny/crossref_metadata_2025 huggingface dataset:
Development, Evolution, and Episodic Charge History of Pop-up Structures in Southeast Abu Dhabi, UAE
Authors: Guevara Jose Manuel , Jubb Mary Grace , Seliem Abdulla , Camacho Hilario , Lozano Jorge Mario
Published: December 2021

The main goal of this paper is contributing to the understanding to the structural geology, development, and evolution of traps associated with strike-slip restraining bend and restraining step-over structures as a key petroleum system element in southeastern Abu Dhabi. We introduce a preliminary classification scheme for these relatively small, low-relief features defined here as pop-up structures. These structures represent different evolutionary stages of strike-slip restraining bends formed along prominent WNW-trending strike-slip fault systems in southeastern Abu Dhabi. The proposed classification scheme was summarized as a chart to illustrate the correlation between the degree of structural deformation and seal integrity, and estimates the likelihood of finding multiple, vertically stacked, productive reservoirs. It also leads to a more detailed discussion on others important characteristics of pop-up structures and provides a better understanding of sealing mechanisms such as fault juxtaposition, fault throw analysis, fault slip tendency, fault rock processes, and the role of the development of hybrid flower structures in the area. We will also show a simple case study based on two exploratory wells that targeted two pop-up structures with different degrees of deformation in southeast Abu Dhabi. This case study illustrates the complex relationship between pop-up evolution, timing of trap formation, seal integrity, trap preservation, and multiple petroleum generation and migration events. Pop-up structures are linked to multiple episodes of trap and seal evolution, where several episodes of hydrocarbon migration, charge, and leaking of hydrocarbons may occur.
Thermally Controlled Fluid to Reduce Formation Breakdown Pressures in Tight Gas Reservoirs
Authors: Almarri Misfer J , AlTammar Murtadha J , Alruwaili Khalid M , Zheng Shuang
Published: December 2021

High breakdown pressure is one of the major challenges in deep tight gas reservoirs. In certain wells, achieving breakdown pressures within the completion tubular yield limit is not possible, and those zones may have to be abandoned without fracturing. Using thermally controlled fluid can lower the formation temperature and ultimately reduce the stresses of the tight gas reservoir formation near the wellbore. The objective of this study is to prove numerically that having a cooled near-wellbore region is a feasible and effective solution to reduce the breakdown pressure. An integrated hydraulic fracturing and reservoir simulator that has been developed at the University of Texas at Austin is utilized for this study. The simulator is a non-isothermal, multi-phase black-oil flow in reservoir, fracture, and wellbore domains. It was found that using thermally controlled fluid is effective in reducing breakdown pressure. Bottomhole Pressure (BHP) decreased by up to around 60% when the temperature of the near-wellbore region is reduced by 60 °F under the simulated conditions in this study. Injecting thermally controlled fluid did not only reduce the high breakdown pressure but also improve the hydraulic fractures efficiency and complexity. This technique is novel and has not been studied in depth in the literature. Utilizing thermally controlled fluid can be a cost effective solution to reduce high breakdown pressure in tight gas reservoirs.
Addressing Paraffin Deposition Challenges Through New Technologies
Authors: Gon Saugata , Russell Christopher , Baack Kasper Koert Jan , Blackwood Heather , Hase Alfred
Published: December 2021

Paraffin deposition is a common challenge for production facilities globally where production fluid/process surface temperature cools down and reach below the wax appearance temperature (WAT) of the oil. Although chemical treatment is used widely for suitable mitigation of wax deposition, conventional test methods like cold finger often fail to recommend the right product for the field. The current study will present development of two new technologies PARA-Window and Dynamic Paraffin Deposition Cell (DPDC)to address such limitations.

Large temperature gradient between bulk oil and cold surface has been identified as a major limitation of cold finger. To address this, PARA-Window has been developed to capture the paraffin deposition at a more realistic temperature gradient (5°C) between the bulk oil and surface temperature using a NIR optical probe. Absence of brine and lack of shear has been identified as another limitation of cold finger technique. DPDC has been developed to study paraffin deposition and chemical effectiveness in presence of brine. Specially designed cells are placed horizontally inside a shaker bath to achieve good mixing between oil and water for DPDC application.

A prior study by Russell et al., (2019) showed the effectiveness of PARA-Window in capturing deposition phenomena of higher molecular weight paraffin chains that resemble closely to field deposits under narrow temperature gradient around WAT. Conventional test methods fail to capture meaningful product differentiation in most oils under such conditions and hence can only recommend a crystal modifier type of paraffin chemistries. PARA-Window technique can expand product selection to other type of paraffin chemistries (paraffin crystal modifiers, dispersants and solvents) as shown earlier by Russell et al., (2021). The usage of DPDC allows us to create a dynamic mixing condition inside the test cells with both oil and water under a condition similar to production pipe systems. This allows DPDC to assess water effect on paraffin chemistries (crystal modifiers and dispersants).

This study presents the usage of these two new technologies to screen performance of different types of paraffin chemistries on select oils and their advantages over cold finger. The results identify how mimicking field conditions using these new technologies can capture new insights into paraffin products.
Insights on Water Sources for Injection Development of Large Oilfields in Southeast Iraq and Appraisal of Paleogene Shallow Water Source Formation
Authors: Qin Guosheng , Wang Youjing
Published: December 2021

As many large oilfields in southeast Iraq entered the final stage of depletion development, water injection appears to be the most economical and technically feasible method to enhance oil recovery. Considering the shortage of freshwater and huge investment in seawater supply project, it is very important to appraise and optimize the favorable shallow water source formation to ensure sufficient water injection supply.

Based on regional seismic, well data, core analysis and production test data, Paleogene sequence stratigraphy was determined by integrating well and seismic interpretation. Under framework of sequence stratigraphy, the sedimentary evolution of main water source formations was characterized. Subsequently, combined with core analysis and special logging data, the petrophysical characteristics of the formations were evaluated, and the volume of the regional water source was estimated.

The research shows that: 1) Dammam limestone and Ghar sandstone are the two main Paleogene shallow water source formations; 2) Dammama developed carbonate shelf, from southwest to northeast, the formation thickness decrease with the sedimentary evolved from inner slope to out slope. Expose and dissolution increased the porosity which is favorable for water storage; 3) Ghar developed alluvial and delta, from southwest to northeast, the formation thickness increase with the sedimentary evolved from alluvial fan, alluvial river to delta. Delta developed abundant and unconsolidated sandstone with high porosity and permeability; 4) The water sample analysis showed the water belong to Cacl2 type with total dissolved solids greater than 250,000 ppm which indicated well sealing condition. Production tests have shown that both Dammam and Ghar have a water supply capacity of 8,000-10,000 barrels per day. The preliminary evaluation of the water volume in the Ghar area can up to 1 trillion barrels.

Paleogene shallow water formation is currently the most realistic and economic water source choice for water injection to enhance oil recovery in large oil fields in southeastern Iraq. Dammam formation and Ghar formation of Paleogene had the characteristics of shallow buried, good water quality and sufficient reserves. Thus, they are the preferred target water source formations for injection development of large oilfields in southeastern Iraq.
The Gaia Explorer, a Powerful Search Platform
Authors: Du Bernard Xavier , Gallon Jonathan , Massot Jérôme
Published: December 2021

After two years of development, the GAIA Explorer is now ready to assist Geoscientists at Total! This knowledge platform works like a little Google, but with a focus solely on Geosciences - for the time being. The main goal of the GAIA Explorer is to save time finding the right information. Therefore, it is particularly useful for datarooms or after business acquisitions to quickly digest the knowledge, but also for feeding databases, exploration syntheses, reservoir studies, or even staff onboarding specially when remote working. With this additional time, Geoscientists can focus on tasks with added value, such as to synthesize, find analogies or propose alternative scenarios.

This new companion automatically organizes and extracts knowledge from a large number of unstructured technical documents by using Machine Learning (ML). All the models relie on Google Cloud Platform (GCP) and have been trained on our own datasets, which cover main petroleum domains such as geosciences and operations. First, the layout of more than 75,000 document pages were analyzed for training a segmentation model, which extracts three types of content (text, images and tables). Secondly, the text content extracted from about 6,500 documents labelled amongst 30 classes was used to train a model for document classification. Thirdly, more than 55,000 images were categorized amongst 45 classes to customize a model of image classification covering a large panel of figures such as maps, logs, seismic sections, or core pictures. Finally, all the terms (n-grams) extracted from objects are compared with an inhouse thesaurus to automatically tag related topics such as basin, field, geological formation, acquisition, measure. All these elementary bricks are connected and used for feeding a knowledge database that can be quickly and exhaustively searched.

Today, the GAIA Explorer searches within texts, images and tables from a corpus (document collection), which can be made up of both technical and operational reports, meeting presentations and academic publications. By combining queries (keywords or natural language) with a large array of filters (by classes and topics), the outcomes are easily refined and exploitable. Since the release of a production version in February 2021 at Total, about 180 users for 30 projects regularly use the tool for exploration and development purposes. This first version is following a continuous training cycle including active learning and, preliminary user feedback is good and admits that some information would have been difficult to locate without the GAIA Explorer.

In the future, the GAIA Explorer could be significantly improved by implementing knowledge graph based on an ontology dedicated specific to petroleum domains. Along with the help of Specialists in related activities such as drilling, project or contract, the tool could cover the complete range of upstream topics and be useful for other business with time.
Introducing New 22" PDC Bit for Drilling Complex Shallow Sections in a Giant Field in the Middle East
Authors: Franco Nata Miranda , Javay Alexandre Jean Robert , Al Moselhy Mohamed Essam Abdelmoneim , ElAssy Mahmoud Mohamed Osama Mohamed Saeifeldin
Published: December 2021

Drilling a 22" section across interbedded, high-impact, and abrasive formations has historically been challenging in giant fields in the Middle East. The section typically ranges from 3,000 ft to 4,000 ft long and requires three to four runs to reach the casing point with conventional TCI bits. This paper covers the introduction of a new 22" PDC bit design run on rotary assembly, which has spectacularly improved the drilling performance over the conventional tricone bits.

The introduction of this new 22" PDC bit design followed a comprehensive engineering approach. Starting with the simulation of rock properties such as compressive strength, abrasiveness, and impact, a fit-for-purpose bit design was manufactured to address the needed cutting structure, number of blades, and depth of cut for the section. The downhole drilling dynamics were also thoroughly analyzed, and the bottom hole assembly configuration was revisited to match up with the new bit structure. Within the dedicated continuous improvement workflow set by the service company, the bit pattern was further optimized after the initial field trials.

After an in-depth analysis of the various formation properties and their impact on bit life, the 22" section was divided into two target runs. The upper part has high-impact and interbedded layers, and the lower part has high abrasiveness and formation compressive strength. In the upper part, the TCI bits had previously shown relatively good performance with acceptable ROP, while the PDC bits experienced damage to their cutting structure. As the impacts were lower in the bottom part, the PDC bit design was selected for the second run to the casing point, which resulted in significantly higher ROP and a longer lifetime than the TCI runs. The 2-bit strategy, spudding the section with the TCI bit and completing it with the PDC bit on rotary assembly, translated into a significant improvement of ROP by 32%. In addition to saving rig time, the overall number of bit runs was reduced by 29%, resulting in cost savings by using fewer bits. Drilling the section in two runs has now become the norm, and this winning strategy was adopted as the new standard for drilling the 22" hole section.

The introduction of the 22" PDC bit on rotary drive returned excellent results and record-breaking ROP performance. While the 22" PDC cost might seem prohibitive, the substantial rig time savings proved this solution to be very economical. Further development of this initiative to other basins in the Middle East or elsewhere will mutually benefit both the operator and service company.
Artificial Intelligence for Infill Well Placement and Design Optimization in Multi-layered/stacked Reservoirs Under Subsurface Uncertainty
Authors: Su Shi , Schulze-Riegert Ralf , Mustapha Hussein , Lang Philipp , Kada Kloucha Chakib
Published: December 2021

Effective well placement and design planning accounts for subsurface uncertainties to estimate production and economic outcomes. Reservoir modelling and simulation workflows build on ensemble approaches to manage uncertainties for production forecasting. Ensemble generation and interpretation requires a higher degree of automation analytics and artificial intelligence for fast value extraction and decision support. This work develops practical intelligent workflow steps for a robust infill well placement and design scenario in multi-layered/stacked reservoirs under uncertainty.

Potential well targets are classified by an opportunity index defined by a combination of rock and hydrocarbon flow properties as well as connected volumes above a minimum economic volume. Unsupervised learning techniques are applied to automate the search for alternative target areas, so-called hotspot regions. Supervised machine/learning models are used to predict infill well performance based on simulated and/or past production experience. A stochastic evaluation including all ensemble cases is used to capture uncertainty. Vertical, deviated, horizontal and multilateral wells are proposed to optimally target single or connect to multiple hotspot regions under technical and economic constraints.

A structured workflow design is applied to a multi-layered/stacked reservoir model. Subsurface uncertainties are described and captured by multiple model realizations, which are constrained in areas of historical wells. An infill well program for a multi-layered/stacked reservoir is defined for incremental production increase under economic constraints.

This work shows how robust well location and design builds on the full ensemble of cases with a high degree of automation using analytics and machine-learning techniques. Both production and economic targets are calculated and compared to a reference case for robust solution verification and probability of success.

In conclusion, an overall reservoir-driven field development strategy is required for efficient execution. However, automation is well applicable to repetitive workflow steps which includes hotspot search in an ensemble of validated reservoir models.

This work presents an integrated, intelligent solution for informed decision making on infill drilling locations and refined well design. Higher degree of automation with embedded intelligence are discussed from case generation to hotspot identification. Aspects of model calibration in a producing field environment are addressed.
Thinking Different Approach to Optimize Your Treaters
Authors: Singh Anand Kumar , Alobeidli Aysha , Bakthavachsalam Venugopal
Published: December 2021

Natural gas coming from the well contains hydrocarbons, CO2, H2S, and water together with many other impurities. Molecular sieve treatment of the gas is required to make it suitable for the various applications. The several process and parameters considerations contribute to the reliable and optimized operation of molecular sieve natural gas treaters.

The journey of this molecular sieve treater optimization commenced by conducting a thorough systematic study of all existing treater performance by considering various operating critical parameter. The technical feasibility studies were completed covering all the aspects like evaluating current performance of treater, conducting simulation for future capacity, licensor endorsement, conducting breakthrough test. Finally, study outcomes were implemented through management change process.

The main benefits of optimization of molecular sieve treater process are to extend the service life of molecular sieve which enable us to increase the turnaround cycle of NGL trains. Significant reduction in CAPEX and OPEX cost were realized by reducing new fresh molecular sieve procurement, reducing disposal of molecular sieve waste material and expense of shutdown, achieving 100% HSE.

This paper presents the typical operation issues and challenges in molecular sieve treatment process, best practices adopted for maximizing of existing assets considering the current and design scenarios, and performance improvement, which result to extend molecular sieve life, increase of NGL shutdown cycle and flaring reduction in trains.
Effect of Nanocellulose in Cement Systems
Authors: Kumar Animesh , Bhaisora Devesh , Dange Mikhil
Published: December 2021

Cellulose, the one of the most abundant biomaterials available in nature, is a polymer with cellobiose as the smallest repeating unit, with a degree of polymerization that can go up to 1000 for wood cellulose. The strength-to-weight ratio of nanocellulose is eight times greater than steel (Patchiya Phanthong et al). Nanocellulose in suspension (NCS) at a varied concentration helps increase properties of cement without changing the density of the cement slurry. Being mindful of challenges in oil and gas wells, efforts were made to enhance cement properties using nanocellulose within conventional and water-extended cement systems.

Samples of 15.8-ppg conventional and 12 ppg water-extended cements were prepared by varying the proportion of nanocellulose within an aqueous suspension. Rheology, sedimentation, compressive strength and mechanical properties were analyzed for a conventional 15.8-ppg cement system with varying NCS proportions of 0, 2, 4, and 5% by weight of cement (BWOC). Similar work was performed for a 12 ppg water-extended cement system by varying NCS differently in proportions of 0, 5, 10, and 20% BWOC.

Two-inch cubes were set at 170°F for 24 hours for each sample. They were crushed using hydraulic crush compressive strength equipment, and the force used to break the sample was recorded. Compressive strength for this cement system was measured to be 2450, 3250, 3450, and 3875 psi, respectively, for samples with 0, 2, 4, and 5% BWOC concentrations of NCS. An increase in the strength of cement with an increase in NCS percentage was observed for the 15.8-ppg slurry design, which may be attributed to the size and shape of the NCS. However, similar study carried out with 12 ppg water extended slurries showed decrease in overall compressive strength. Nano-sized particles fill the pores within the sample, impacting structural network development. Additionally, cellulose, having a fiber-like structure, may provide inter-particulate reinforcement.

Based on the results of the 15.8-ppg cement system and the high tensile strength of nanocellulose, it can be determined that NCS has a positive effect for increasing mechanical properties. By applying nanocellulose, a tailored cement system (dependable barrier) can be designed to minimize risk and maximize production from oil and gas wells.

Nanocellulose is of increasing interest for a range of applications relevant to the fields of material science and biomedical engineering because of its renewable nature, anisotropic shape, excellent mechanical properties, good biocompatibility, tailorable surface chemistry, and interesting optical properties. Low-volume NCS additions can alter the structure of the cured cement system and increase its mechanical properties. This reinforcing mechanism may provide a new opportunity for achieving higher strength cementitious materials.
Integrated Geomechanical Operations for Successful Field Development: A Case Study from Western Offshore, India
Authors: Bagga Pawandeep , Kidambi Tapan , Sharma Ashish , Panchakarla Anjana , Kulkarni Aditee
Published: December 2021

This paper deals with the field development study for an offshore field in the western part of India. The main points of focus are holistic execution of integrated workflows for the delivery of subsea oil and gas wells from a jack up platform in this region. Given that the encountered formations encountered in wells posed significant challenges during the drilling phase, a field level geomechanics study was commissioned to understand and mitigate any challenges and effect smooth drilling and logging operations. Understanding the geomechanical effects by analysing the offset wells drilled in the region provided significant insights into the potential challenges faced while exploring target formations.

The proposed well locations were drilled in a structurally complex geological setting. From the analysis of previously drilled wells in the region, it was evident that the variation in insitu properties of the lithologies and the extreme heterogeneity and vugular nature of the encountered carbonates caused significant drillability issues with subsequent losses, excessive cuttings, and several back reaming cycles impacting rig time and leading to generally poor borehole conditions. On the other hand, the shales encountered at shallower depths presented a different challenge, especially with a high swelling tendency, adding to progressively worsening hole conditions and significant fluid invasion. Finally, the basal clastics and the depleted zones with variable rock strengths added to the borehole instability issues, with particular zones projecting losses while others showed influxes.

In light of such a plethora of issues, an integrated approach including dynamic real time monitoring of operations, structured LWD and wireline logging programmes, a high level petrophysics, formation evaluation and borehole acoustics for shear radial profiling was carried out. A fit for purpose geomechanical model was built encompassing the results of these analyses and was continually updated in real time during the operations phase. Given the variability in the pressures, temperatures and operational mud weights in each section, execution for successful delivery of the wells was further aided by identification of the optimal mud systems, critical casing setting depths and real time drilling optimization, ensuring good borehole quality throughout for further logging and testing programmes.
The New Technological Frontiers of CO2 and Hydrogen Transportation Via Pipelines
Authors: Arcangeletti Giorgio , Scarsciafratte Daniele , Leporini Mariella , Orselli Benedetto , Santicchia Angelo , Torselletti Enrico , Aloigi Elvira
Published: December 2021

COVID-19 pandemic is accelerating the transition to decarbonized energy systems. In this context, major Operators and Contractors are bound to promote innovation and technological development. The paper describes how this is being applied to the design of offshore pipelines that are now required to transport not only Hydrocarbons but also anthropogenic CO2 and low-carbon Hydrogen. In order to evaluate all the new technical challenges presented in designing CO2 and H2 pipelines, a state of art has been carried out and is here presented focusing on all the new technical aspects associated to the main disciplines involved in the pipeline network design. Different technical aspects (such as performances evaluation of Equation of State in CCS, Design Standards application to both CO2 and hydrogen pipelines, energy capacity of hydrogen pipelines and others) have been also analytically or numerically addressed simulating credible pipeline operating scenarios. To achieve that, an intensive engineering effort is being dedicated to the development of knowledge, engineering tools, methods and procedures that will be the basis for the execution of future projects concerning H2 and CO2 transportation and storage. A particular focus has been dedicated to offshore pipeline design both for new installation and repurposing of existing ones. In parallel, the cooperation started between Operators, Contractors, Manufacturers, Institutions and Universities, as described in the present paper, acts as a "booster" for the consolidation of knowledge and for the advancing of technology to put in place to overcome those new challenges. Recommendations are made in relation to the gaps found in experimental evidence present in literature and gaps in Standards coverage for the proper pipeline design in those new scenarios.
Machine Learning as a Silent Observer of Advanced Geoscience Interpretation
Authors: Sajid Muhammad
Published: December 2021

Machine learning is proving its successes in all fields of life including medical, automotive, planning, engineering, etc. In the world of geoscience, ML showed impressive results in seismic fault interpretation, advance seismic attributes analysis, facies classification, and geobodies extraction such as channels, carbonates, and salt, etc. One of the challenges faced in geoscience is the availability of label data which is one of the most time-consuming requirements in supervised deep learning. In this paper, an advanced learning approach is proposed for geoscience where the machine observes the seismic interpretation activities and learns simultaneously as the interpretation progresses. Initial testing showed that through the proposed method along with transfer learning, machine learning performance is highly effective, and the machine accurately predicts features requiring minor post prediction filtering to be accepted as the optimal interpretation.
Industry First Subsea Reentry Multilateral Wells: Case Study
Authors: Ragaglia Simone , Carotenuto Antonio , Napoleone Luca , De Dominicis Guerino , Sakharov Sergey , Latypov Artur , Newman Robert , Guevara Carlos , Rachi Hakim , Revheim Kjell
Published: December 2021

To rapidly increase production from the Goliat Field without adding costly subsea equipment and infrastructure or mobilizing a high-end subsea construction vessel, an operator transformed two single-bore subsea wells into multilateral producers with independently controlled branches.

A multidisciplinary team was assigned to perform a feasibility study for the introduction of multilateral wells. Work started with a reservoir geomechanics/wellbore stability review, based on which well construction/completion basis of design was made. The design and operations sequence were analyzed by a well engineering team. As a result, the main risks, uncertainties, and assumptions were clarified. Two candidate wells were identified, and then a multidisciplinary team was assigned to manage the project, finalize design, initiate procurement, and write procedures. Workshop preparation was closely monitored and reported on a weekly basis. The onshore team closely followed up and supported operational execution.

The new laterals were added to the existing wells, and multilateral junctions were installed and tested. An intelligent completion was installed, and independent branch production started. In addition, the estimated reduction in generation of CO2 is estimated to be between 10 to 20 thousand metric tons per well as compared with drilling two new subsea wells and installing the associated infrastructure.

The technology enables an exploration and production (E&P) company to introduce subsea reentry multilateral technology to increase production while minimizing costs. The process includes well candidate identification, planning, and execution. This practical example can be used for future reference by drilling and production-focused petroleum industry professionals to better understand the benefits and limitations of existing technologies.
Quantitative Evaluation of Well Blowout Risk and Oil Spill Mitigation Measures
Authors: Zausa Fabrizio , Besenzoni Luigi , Caia Alessandro , Mizrak Seda
Published: December 2021

The disaster of Macondo of 2010 changed the rules in reliability and safety standards during drilling operations. New regulations were developed in order to improve the control level on blowout risk, and all upstream operators adopted innovative technologies capable to reduce the potential risk of uncontrolled release, either by decreasing its frequency of occurrence or the expected impacts. The objective of this paper is to present a Quantitative Risk Analysis (QRA) of well blowout and measure the beneficial contribution of intervention technologies in terms of expected reduction of spill volume and associated costs.

The QRA is applied to any kind of well operation (drilling, completion, workover, light intervention) and well type. The methodology relies upon different risk analysis techniques able to quantify the residual blowout risk, as well as the mitigation provided by each technology. Through Fault Tree Analysis (FTA), a value of blowout probability is calculated for each well operation. The initial blowout condition is associated with a blowout flow rate, calculated with fluid dynamic computational models depending on well flow path and release point into the environment. The evolution of each release scenario is then studied with the use of Event Tree Analysis (ETA), where a set of events, able to reduce or stop the flow, are considered with their probability of success and occurrence time (well bridging, water coning, surface intervention through killing/capping techniques, relief well operations). The value of each intervention is estimated through Decision Tree Analysis (DTA), calculating the amount of spill volume reduction and avoided spill costs.

Results of spill volume and cost reduction are calculated for a set of specific wells, considering the application of killing/capping systems as well as Eni innovative technologies. The benefit of these interventions is measured in terms of Expected Monetary Value (EMV) in relation to a potential release extinguished by a relief well, which is the decisive intervention to stop the blowout, considered as the worst case scenario. Surface interventions with killing/capping techniques are the major contributors to the reduction of blowout impacts, and all additional measures which can be adopted should act in the fastest way possible before the arrival of heavy capping stack system.

The main innovative contribution of the proposed QRA methodology is the association of an expected economic value to post-blowout mitigation techniques, which takes into account all possible uncertainties related to their success and intervention time. Moreover, by evaluating an economic impact of the residual spill cost, it is possible to prioritize and increase the overall efficiency of the oil spill response plan for each operational and geographical context, and improve the control on blowout risk mitigation process.
First Permanent Inflow Monitoring Experience in a Smart-Liner, Intelligent-Completion, Multi-Lateral Adnoc Offshore Well
Authors: El Maimouni Fadwa , Mirza Omar , Aissaoui Abdelkader , Almstrong Shawn , Bigno Yann , Keshtta Osama , Almazrouei Gaya , Gharbawi Shihabeldin , Rashed Rasha , Elder Craig , Leung Edmund
Published: December 2021

The scope of this paper is to share a field experience with permanent inflow tracer deployment and monitoring of an intelligent multi-lateral well, completed with Smart-Liner (Limited Entry Liner). It will describe what ADNOC Offshore has learnt through inflow tracing clean up surveillance from several restarts and steady state production through inflow modelling interpretation techniques.

This passive method of permanent monitoring technology utilizes chemistry and materials expertise to design tracers that release signature responses when they come into contact with either in-situ oil or formation water. The chemical tracer technology enables wireless monitoring capabilities for up to five years. Unique chemical tracers are embedded in porous polymer matrix inside tracer carriers along select locations in the lower completion to correlate where the oil and water is flowing in a production well. Interpreting tracer signals can provide zonal rate information by inducing transients to create tracer signals that are transported by flow to surface and captured in sample bottles for analysis. The measured signals are matched with models through history matching to yield zonal rate estimates.

ADNOC Offshore has installed inflow tracers in an intelligent multi-lateral well to monitor laterals’ contributions, to verify new completion technology, and to estimate the flow profile from individual sections of Smart-Liner, run for the first time in the field. The interpretation results have been able to characterize inflow performance without any intervention in the well. Several restart and steady state surveys are planned to understand some key characteristics of the well completion and reveal how the well has changed since it was put on production. This technology will help allocate commingled production to the three laterals. The use of inflow tracers will provide multiple inflow surveys that will reduce operational risk, well site personnel, costs and will improve reservoir management practices. Permanent inflow tracing is expected to change the way production monitoring can be performed, especially in advanced wells where PLTs or Fiber Optic technology cannot access multi-laterals.
A New Down Hole Tool and Approach To Release Differentially Stuck Pipe
Authors: Machocki Krzysztof Karol , Aljohar Abdulwahab , Zhan David , Abegunde Ayodeji
Published: December 2021

A new down hole system and method to use for releasing stuck pipes is presented. New system design, features and limits are compared to commonly used techniques for releasing stuck pipe showing benefits of the new system when dealing with differential stuck pipe incidents.

The new down hole system is capable to deliver much greater forces when compared to jars and other down hole accelerators near the stuck point. This system can generate over 40G`s lateral forces continuously down the hole acting on the stuck pipe area. The system can be integrated into a Bottom Hole Assembly (BHA) and activated once drill string become stuck or run as a part of the remediate assembly. Different aspects of two types of assemblies are described outlining the benefits and drawbacks.

The author will discuss in details the background and rationale to the new technology, including a review of differential sticking challenges and functionality of this new system.

The new system was compared to the most commonly used techniques for releasing differentially stuck pipe. Previously not releasable stuck pipe forces of over 1,000,000 lb. can now be overcome with the presented new approach to generate down hole forces near the stuck place. Flexibility in system integration and deployment allows for further optimization in BHA design and cost affective fishing operations in dedicated hole sections. This new approach can be implemented to release the most challenging stuck pipe mechanisms in drilling to minimize NPT and cost associated with stuck pipe, remedial operations and sidetracks. Similar approach can be utilized to release differentially stuck pipes, tubing and completions.

The novelty of this stuck pipe release system is the entire down hole system and operations of the overall system using new approach to generate large shocks down the hole. Additional novelty is related to flexibility during integration and deployment of this system. Similar to current shock tools, this system can be placed in BHA, fishing type assemblies and also pumped down inside of the stuck drill string to save time and cost.
Development of the Surfactant-Based Chemical EOR Formula for Low Permeability Reservoirs
Authors: Zhou Nancy Chun , Lu Meng , Liu Fuchen , Li Wenhong , Li Jianshen , Vaughan Steven , Trine Eric , Li Zhitao , Dean Matt , Britton Chris
Published: December 2021

Based on the results of the foam flooding for our low permeability reservoirs, we have explored the possibility of using low interfacial tension (IFT) surfactants to improve oil recovery. The objective of this work is to develop a robust low-tension surfactant formula through lab experiments to investigate several key factors for surfactant-based chemical flooding.

Microemulsion phase behavior and aqueous solubility experiments at reservoir temperature were performed to develop the surfactant formula. After reviewing surfactant processes in literature and evaluating over 200 formulas using commercially available surfactants, we found that we may have long ignored the challenges of achieving aqueous stability and optimal microemulsion phase behavior for surfactant formulations in low salinity environments. A surfactant formula with a low IFT does not always result in a good microemulsion phase behavior. Therefore, a novel synergistic blend with two surfactants in the formulation was developed with a cost-effective nonionic surfactant. The formula exhibits an increased aqueous solubility, a lower optimum salinity, and an ultra-low IFT in the range of 10-4 mN/m. There were challenges of using a spinning drop tensiometer to measure the IFT of the black crude oil and the injection water at reservoir conditions. We managed the process and studied the IFTs of formulas with good Winsor type III phase behavior results. Several microemulsion phase behavior test methods were investigated, and a practical and rapid test method is proposed to be used in the field under operational conditions.

Reservoir core flooding experiments including SP (surfactant-polymer) and LTG (low-tension-gas) were conducted to evaluate the oil recovery. SP flooding with a selected polymer for mobility control and a co-solvent recovered 76% of the waterflood residual oil. Furthermore, 98% residual crude oil recovery was achieved by LTG flooding through using an additional foaming agent and nitrogen. These results demonstrate a favorable mobilization and displacement of the residual oil for low permeability reservoirs.

In summary, microemulsion phase behavior and aqueous solubility tests were used to develop coreflood formulations for low salinity, low temperature conditions. The formulation achieved significant oil recovery for both SP flooding and LTG flooding. Key factors for the low-tension surfactant-based chemical flooding are good microemulsion phase behavior, a reasonably aqueous stability, and a decent low IFT.
Formation Heterogeneity Effect on Steam Injection and Propagation
Authors: Batarseh Sameeh , Assiri Wisam , SanRoman Alerigi Damian , Khaldi Bander
Published: December 2021

The objective of this work is to evaluate and understand steam injection in heterogonous formation utilizing a state-of-the-art experimental apparatus. Heat transfer and efficiency for steam injection are evaluated in heterogeneous formation and compared with homogenous formation. The information obtained from the apparatus provided the key in designing effective steam injection for optimized recovery in heterogeneous formations.

This paper presents several successful experimental works and proposes solutions to overcome the challenges produced from heavy oil reservoirs. The technology utilizes advanced thermal apparatus to improve heat penetration depth into the formation and efficiency of the thermal heating. Steam is the most used technology due to its high latent heat capacity, cost and maturity. Steam injection should be carefully planned to ensure the injectivity to the target. Heterogeneity adds to the complexity of the operation, as the steam will propagate in different orientations. This study provides the key element to understand steam propagation to maximize the recovery efficiency. The experiments were carried out using heavy oil apparatus, which is designed to accurately simulate reservoir conditions. It measures one meter in length by one meter in width by one and a half meter in height. It has 65 thermocouples, 24 acoustic transducers, 9 vertical wellbores, 9 horizontal wellbores; these data are used for modeling and simulation. The apparatus can use sand or blocks.

Thermal technology is very effective to mobilize heavy and viscous oil; steam injection has been successfully and widely deployed due to its reasonable cost, maturity, and efficient thermal transfer to reservoir fluids. Understanding the formation is vital to ensure successful steam-based stimulation, especially in heterogonous reservoirs. To this end, an apparatus was designed to evaluate steam injection in heterogonous formations. This is one-of-a kind studies that evaluates heterogeneity effect at a large scale and provides detailed analysis. First, steam is injected in homogenous formation to establish a baseline of heat propagation in formation. Second, the apparatus is filled in layers resembling a heterogonous formation, and steam is injected at same conditions (i.e., wellbore depth and injection rate and pressure). The device collected a real-time temperature map using 65 thermocouples. 3D graph and animations are plotted to visualize and evaluate the pattern and trend of steam propagation in both homogenous and heterogeneous formations.

The apparatus is uniquely deigned to evaluate different scenarios that simulate the field and wellbores more accurately. Due to its volume (one cubic meter), the device is the largest apparatus in literature, and flexibility, the device enables the replication of a heterogeneous formation. The amount of data and information gathered, make the apparatus unique and provide key elements to drive successful steam injection operations.
The Optimization of Infill Well Fracturing Using an Integrated Numerical Simulation Method of Fracturing and Production Processes
Authors: Wei Shiming , Jin Yan , Liu Xing , Xia Yang
Published: December 2021

New wells are continuously drilled to improve the recovery of shale gas reservoirs. Production processes of parent wells will induce stress changes in the reservoir and then affect infill wells’ fracturing design. In this paper, we employed an integrated numerical method to simulate the hydraulic fracturing and production processes with single one method, thus the fracturing scheme of the infill well can be optimized. The integrated numerical method is based on the finite element method (FEM), which is named as the discontinuous discrete fracture method (DDFM). The DDFM can be used with conventional finite element mesh, which is perfectly compatible with the discrete fracture model (DFM). The fully coupled solution of DDFM is validated by two problems, including Mandel problem's analytical solution and the numerical solutions of the single fracture propagation. When predict the shale gas production, a new diffusion equation is modified to describe the shale gas flow, and the simulation results showed a good agreement with the field data. At last, this paper takes an infill well construction in a shale gas reservoir in south China as an example. The hydraulic fractures of parent wells are interpreted from micro-seismic data and described with DFM to reduce the computational cost. Then the infill well's hydraulic fractures are described using DDFM. After simulating the production process of two parent wells, we get the current formation pressure and stress state. Aims at obtaining the maximum profit of the whole well region, by comparing the gas production of different fracturing schemes, we can choose the optimal fracturing scheme of the infill well.
Addressing Fouling by Qualifying Chemical Additives Using Novel Technologies
Authors: Farrell Andrew Robert , Frigo Dario Marcello , Graham Gordon Michael , Stalker Robert , Diestre Redondo Ernesto Ivan , Lorenzo María de la O Masa
Published: December 2021

Fouling of heat exchangers and production of stable emulsions in desalting units can present significant challenges in refinery operations. Often these difficulties occur due to the concurrent processing of two or more crude oils that are incompatible under process conditions. This paper describes a significant development in laboratory techniques for studying these issues and evaluating mitigation strategies.

Asphaltenes compatibility was evaluated for oil mixtures that may be co-processed in the refinery using a deposition flow rig, and the results were compared with those obtained with more conventional tests: blending stability analysis by light scattering and various screening methods. The flow rig mimics the process conditions (elevated pressure, high temperature, flow-induced shear) and identifies whether deposition or precipitation will occur. The former can cause fouling of heat exchangers whereas the latter produces solids that can stabilize emulsions in the desalter.

By varying the proportions of oils that were co-injected into the deposition flow rig, the range within which mixtures were unstable was found. By flowing through a capillary (to mimic a heat exchanger) and in-line filter, it was possible to identify whether precipitation of suspended flocs or fouling of the heat exchanger itself was the likely issue for each mixture.

Emulsion-stability tests were conducted using a pressurized rig with an ersatz separator to mimic the desalting unit; results were compared with those obtained in conventional, ambient-pressure bottle tests. Oil(s) and refinery wash water were injected, mixed under representative shear, and allowed to separate within the typical residence time of the desalter. Chemical additives were tested to identify those that were effective at controlling any observed problems.

Results obtained in either flow rig (using representative pressure, temperature, and shear) did not always match those obtained using conventional methods. Asphaltenes fouling occurred under conditions where it was not predicted by screening tests that were conducted at conditions not representative of the process and did not occur under conditions where it was predicted. Differences were also observed between the emulsion stability observed in bottle versus rig tests, though these should be viewed as complementary techniques.

This paper presents new laboratory techniques for the prediction and prevention of refinery fouling and emulsion stability. They mimic conditions in the facilities much better than those typically used to date.