bluuebunny/crossref_metadata_2025_split huggingface dataset:
What the Shale are We Talking About!
Authors: Hoxha Besmir Buranaj , Rabe Claudio 
Published: December 2021

Abstract
Shale ‘stability’ has been extensively studied the past few decades in an attempt to understand wellbore instability problems encountered while drilling. Drilling through shale is almost inevitable, it makes up 75 percent of sedimentary rocks. Shale tends to be characterized as having high in-situ stresses, fissile, laminated, with low permeability. However, not all shale are the same, and the problem herein lies where they are all treated as such, in which most cases, has shown to be ineffective. Ironically, shale is predominantly generalized as being "reactive/swelling". Even though this can be true, it is not always the case because not all shale is reactive! In reality, there are many different types of shale: ductile, brittle, carbonaceous, argillaceous, flysch, dispersive, kaolinitic, micro-fractured etc. This study aims to clear many misconceptions and define different types of shale (global case scenarios) and their failing mechanisms that lead to wellbore instability, formation damage and high drilling cost. Afterwards, solutions will be offered, from a filed operation perspective, which will provide guidelines for stabilizing various shale based on their failure mechanism. Furthermore, we will define the symptoms for shale instability and propose industry accepted remedies.
Efficient Drilling Technology of Horizontal Wells in the Duverney Block in Canada
Authors: Han Haochen , Yang Guobin , Zhang Guobin , Chen Jia , Chen Peter , Fu Jin , Wang Siqi 
Published: December 2021

Abstract
Recent years, both exploration and development have made considerable progress in the Duverney block shale gas in Canada. However, technical problems exposed in horizontal drilling engineering need to be optimized: 1) Loss is common in shallow formations; 2) High downhole friction torque, low ROP and drilling cuttings accumulation in long horizontal well section; 3) Borehole instability leads to hanger or packer failure; 4) Drill bits and PDM have short servicing life and low efficiency.
Optimization comes from three aspects: (1) Based on previous drilling experience and latest formation condition and development requirement, we design a new well profile for the block taking into drilling safety and further development account;(2) Optimize strong inhibitive, easy-maintenance and high cutting-carrying capacity OBM to ensure the safety requirements in the ultra-long open hole section; (3) BHA and parameters optimization. Optimize drill bit with high-abrasiveness and axial efficiency according to logging data, drillability and UCS. Upgrade conventional PDM into high-performance PDM with even-wall thickness. By means of simulation and calculation, drilling parameters suitable for Duverney block has been optimized.
Based on the optimization above, a stable and efficient well profile has been improved solving hanger failure on-site efficiently and complete with composite casing design (4-1/2 inch plus 5 inch) in reservoir section; a 90/10 oil-water ratio OBM has been optimized and applied onsite; Combined with high performance PDC bit and even-wall PDM as well as optimized drilling parameters, higher ROP and longer horizontal section have been achieved. The optimization has made successful field application results:(1) Completion depth has been deepened gradually, from 18,080 ft in 2013 to 23,208 ft at present, with an increase of 28.3%;(2) Horizontal section length has been increasing dramatically, from 6,190 ft in 2013 to 10,301 ft at present, with an increase of 66.4%;(3) The average drilling cycle has been shortened, from 51 days in 2013 to 26 days at present, with a decrease of 48.8%;(4) The average ROP has increased steadily, from 71.2ft/h in 2013 to 82.12ft/h at present, with an increase of 15.3%; (5) Drilling costs per meter have been significantly reduced, from 442.4 CAD/ft in 2013 to 228.3 CAD/ft at present.
Combining the optimization and matching design above, it has effectively solved the difficulties of the Duverney block drilling engineering and achieved good field application effects: well depth and horizontal section length in the block have been deepened year by year, the drilling cycle and cost have been decreased year by year, as well as the economic effect has been significant. In all, the research achievements provide a practical and effective reference for horizontal wells in other region especially for the unconventional gas.
Successful Approach in Curing Lost Circulation in Depleted Aquifer Formations by Utilizing a Combination of Swelling Polymer & a Shear-Rate Rheology-Dependent Cement System; Case Study in UAE Land Operation
Authors: Saragi Raymond , Husien Mohammad , Sinaga Agus Liber Maradat , Mwansa Peter Levison , Varma Esha Narendra , Hussain Mohamed Qassem , Rocha Michelle C. Santos , Nasrallah Mena , Mohamed Sherif , El Saad Rashad Abo 
Published: December 2021

Abstract
One of the greatest historically unsolved challenges to date in the United Arab Emirates is the failure to effectively cure the severe losses due to poor zonal isolation during drilling and cementing aquifer formations in particular the Dammam, UER &amp; Simsima formations in the BAB field. Continuous efforts have been made to seek and pilot new technologies in UAE land operations to overcome drilling operation challenges, specifically chronic lost circulation in aquifer formations with the commitment to drive a more cost-effective operation and reduce the risk of Non-Productive Time (NPT). The current practice was not providing proper zonal isolation in the surface and intermediate sections. Most of the time aerated drilling was utilized while drilling the lost zones and conduct a top-up cement job to improve zonal isolation, but this results in limited reliability. It was necessary to identify a different approach to cure or significantly reduce the losses which would enable the hole section to be drilled successfully while minimizing operational risks, in a cost-effective manner.
A technique combining two different technologies was selected: a swelling polymer lost-circulation material (LCM) that hydrates and helps reduce flow velocity into the formation, followed by a shear-rate rheology-dependent cement system. This cement system is a tunable and tailored slurry with thixotropic properties and has shown very cost-effective results with high success rates. It was then decided to tailor this approach to Abu Dhabi land operations to maximize wellbore asset value. After four subsequent trials targeting two different aquifer formations, the technique has shown tremendously promising results by successfully curing the losses providing above 80% returns. These combined technologies aim to eliminate or reduce effect of losses during cementing by performing the primary cementing job with complete returns or minor losses across aquifers thus enhancing wellbore integrity during the lifecycle of the well. It is hoped that this will eliminate, or at a minimum reduce production deferrals and subsequently improve plug and abandon (P&amp;A) operations at end of field life.
This paper aims to describe the challenges faced on the first three trials utilizing this technique and the solutions assigned for each trial based on the inputs, such as loss rate, formations interval exposed, design and lab testing for the pumped treatments as well as job execution details along with lesson learned for future jobs.
Integrated Stochastic Inversion Approach Assessing Thin Reservoirs Full Potential in the Prolific Oil-Prone Periphery of Hassi Messaoud Field, Algeria
Authors: Tawfik Mohamed Samy , Nasrine Medjdouba , Annou Sabiha , Ahcene Aiouna , Haddouche Abderaouf , Barling Thomas , Kenef Mohamed 
Published: December 2021

Abstract
Nowadays it become harder, risker and more expensive understanding the reservoir potentiality and design the optimum development plan for challenging thin reservoirs. In a geological complex area, integrated seismic reservoir characterization approach was crucial to unlock the potentiality for the study area, which is located at Oued Mya basin, SE Saharan platform Algeria.
Seismic data analysis is one of the key procedures for characterizing reservoirs and monitoring subsurface properties. Integration of seismic stochastic inversion and geological model will help to demonstrate the link between seismic and reservoir properties more quantitative. The seismic data of region were challenging, with around 30 wells drilled over 400 Km2. To overcome the challenges, the available geological and geophysical data were integrated to construct the reservoir characterization study and reduce drilling uncertainty.
Ensure the reservoir characterization process was constrained by a robust workflow and consistent with the available geophysical, geological, and petrophysical data. Petrophysical interpretation, seismic interpretation, rock physics analysis and Stochastic Inversion processes were carried out. These processes were integrated to characterize the lateral and vertical extent of the lithofacies in five stacked reservoirs across the area of interest to identify the potential delineation of thin reservoirs of nine-meter thickness.
Novel Application of Epoxy Resin to Eliminate Sustained Casing Pressure Without Costly Downhole Well Intervention - Case History from East Kalimantan, Indonesia
Authors: Guna Yogi Adi , Frank Michael , Rochman Novianto , Putra Thomas Herdian Abi , Irvan Mohammad , Fitriansyah Alfatah , Kurniawan Ibnu 
Published: December 2021

Abstract
An operator recorded 1100 psi of sustained casing pressure between a 9-5/8" casing and a 3.5" production tubing annulus seven days after the cementing operation was completed for the 3.5" production tubing. A production logging run was performed, and results indicated gas was flowing from a zone 86 feet below the 9-5/8" casing shoe. As per the operator's standard, such a situation suggests subsequent well completion operations cannot be processed and must be remediated. The most common solution for such situations is to perforate and squeeze to ensure zonal isolation in the zone from which the gas is flowing. Due to the slim tubing size this operation can be difficult, and there exists a high risk of leaving set cement inside the 3.5" tubing. Furthermore, drilling would require extensive time with a coil tubing unit and in the worst case could lead to the loss of the well.
To provide a dependable barrier for long term well integrity, a novel approach consisting of epoxy resin was discussed. A highly ductile, solids-free resin was designed and tailored to seal off communication from the gas source to surface. The void space in the annulus was estimated to be less than 5 bbl. An equipment package was prepared to mix and pump the resin into the annulus. Resin was pumped through the wellhead casing valve using a hesitation squeeze technique with the maximum surface pressure limited to 3000 psi. Once all resin was pumped, the casing valve was closed to allow enough time for the resin to build compressive strength.
The job was planned to be performed in multiple stages consisting of smaller volumes. The job was completed in two stages, and the annular pressure was reduced. On the first job, 1 bbl of resin was mixed and injected into the annulus. The pressure build up was decreased from 550 psi per day to 27 psi per day. To lower the annular pressure further, a second resin job was performed using 0.35 bbl resin volume, which further reduced the annular pressure build up to 25 psi within 3 days. No further stages were performed as this was considered a safe working pressure for the well owner. After 2 months no annular pressure was observed.
The application of this tailored resin helped to improve the wells integrity under these circumstances in this high-pressure gas well. Epoxy resin with its solid-free nature and deep penetration capabilities helped to seal off a very tight flow path. This application of pumping resin through the wellhead to overcome annular gas pressure can be an option when the flow path is strictly limited, or downhole well intervention is very difficult and risky.
Innovative Liner Hanger System Designed for Operational Benefits in Harsh Environments
Authors: Hashmi Ahmad Atef , Riskiawan Arris R , Pedreira Jose Eduardo , Al Marghalani Ahmad 
Published: December 2021

Abstract
Since the beginning of drilling for oil, improving efficiency and reducing the cost of hydrocarbon recovery have been key issues when designing a well. Since then, new methods and techniques have developed the industry. One of the most critical events in the oil and gas industry was the invention of the liner hanger.
Since Liner Hangers are utilized as the primary solution to wellbore construction, they have been designed with such requirements in mind. This paper will deliver an insight to an innovation life cycle where a stakeholder collaborated together to successfully deliver, plan and complete the first 15,000 PSI, 400 °F high pressure- high temperature (HPHT) Liner Hanger designed to overcome the operational obstacles that conventional liner hangers have when deployed with Multistage Frac (MSF) completion systems but still allows for successful operations in cemented completions.
This liner hanger technology has been run in different parts of the world and has proven since the beginning that with all the features included in the designed stages.
Integration Applications of Image and Sonic Data in the Fault-Dominated Carbonate Reservoir in Tarim Basin
Authors: Zhang Yu , Xiao Honglin , Zhang XiaoMing , Liu Haidong , Liu Bo , Wang Wei , Li Shenzhuan , Wei Guo , Liu Xunqi , Yu Daiguo , Wu Jinlong , Zhao Xianran 
Published: December 2021

Abstract
Carbonate reservoir is one of the most complex and important reservoirs in the world. It was confirmed that the slip-strike fault played a crucial role in the fault-dominated carbonate reservoir in Tarim basin. It is challenging to evaluate this kind of reservoir using the open-hole log or seismic data. Identifying and characterizing the fault-dominated carbonate reservoir were the objectives of this case study.
High-definition borehole resistivity image and dipole sonic logs were run in several wells in the research area. It was revealed the detail features of the fault-dominated carbonate reservoir, such as natural fractures, faults or breccias. Compared with the typical geological model of strike-slip faults and outcrop features, the characteristics of the breccia zone and the fracture zone in the strike-slip fault system were summarized from the borehole image interpretation. A unique workflow was innovated with the integration of image and sonic data. Breccias and fractures were observed in the borehole image; and reflections or attenuations in Stoneley waveforms can provide indicating flag for permeable zones. Integrated with the other related geological data like mud logging or cores, the best pay zones in the fault-dominated carbonate reservoir were located.
The characteristics of the strike-slip fault was revealed with the integration of the full-bore formation microimager and dipole shear sonic imager data. The fault core was a typical breccia zone with strong dissolution, which showed good potential in permeability, but it was found that some fault cores were filled with siliceous rock or intrusive rock. The features of the fillings in the fault zone were described based on the image and sonic data. The side cores or geochemical spectroscopy logs data helped to determine the mineralogy of the fillings. The fracture zones had clear responses in the image and sonic data too. The un-filled or half-filled breccia zone were the best zones in the fault-dominated carbonated reservoir. The details of the fault-dominated carbonate reservoir could be used in the future three-dimensional geological modelling.
Litho-Based Pore Scale Waterflooding in Carbonate Reservoirs: A Holistic Approach to Predict Displacement Efficiency
Authors: Ibrahim Mahmoud Mohamed , Bowden Stephen Andrew 
Published: December 2021

Abstract
Grainstones deposited on carbonate ramps are excellent petroleum reservoir formations and are important for energy needs. Waterflooding is routinely used to augment oil recovery and many carbonate fields have long production histories. Future management of these "mature" assets requires knowledge of how oil production can be sustained and enhanced but requires understanding the pore-scale displacement processes. Despite decades of waterflooding in carbonate oilfields a plausible displacement efficiency prediction is not yet trivial. To evaluate waterflooding economics, it is crucial to know the residual oil saturation (Sor) and where oil is entrapped by capillarity in the reservoir. Microfluidic waterflooding experiments provide a means to visualize pore-scale phenomena within different carbonate minerals (calcite, dolomite, and gypsum) and petrographic textures, to estimate microscopic displacement efficiency. By using analogues of carbonate ramp reservoir-lithologies (in terms of texture, unstructured-irregular pore networks and varied mineralogical compositions) realistic evaluations of displacement efficiency were determined for different mineralogical compositions. The quantitative test results matched closely Arab formation SCAL published data.
It was determined that multi-mineralic grainstones undergoing waterflood likely experience contemporaneous imbibition and drainage, giving rise to complex multiphase flow due to the existence of different states of wettability. This wettability contrast induces "capillary jumps" across wettability-boundaries at the interface between different lamina or textures. These "capillary leaps" account for increase in oil recovery as they occur but leave behind bypassed oil. Consequently poly-mineralic arrangements have a lower oil recovery compared to mono-mineralic cases.
It was observed that distinct Sor are achieved at different injected pore volumes, despite sharing similar porosity & permeability, thus the relationship between Sor and porosity/permeability is weak. Thus, predicting waterflooding efficiency requires the different carbonate minerals Sor to be incorporated in dynamic simulation.
Remediating a Landslide Affected Well for Subsequent Abandonment - Challenges Overcome and Solutions Applied
Authors: Cirstian Felicia , Sauter Jason Patrick , Vintila Constantin , Albulescu Gheorghe , Badescu Cosmin Constantin , Ene Maximilian 
Published: December 2021

Abstract
Control/Tracking Number 21 ADIP-P-4946-SPE

Abstract Description
This paper will present a case study to describe the well integrity complications of an onshore gas well in Romania affected by a landslide event, the challenges overcome during the land consolidation/excavation around the well, and the remediation solution of the well's casings. After being severely affected by a landslide, the subject well stopped production having a surface deviation from the original position of 5m and a landslide plane at cca 25m. The primary scope of the project was to restore the integrity of the well in order to safely abandon the well so that people and environment were not exposed to risk or danger.
The project was elaborated through a collaborative effort of multidisciplinary teams including company personnel, such as well integrity engineers, completion engineers, geologists, abandonment team members, civil engineers, HSSE and construction, as well as several service providers. As part of the Phase to consolidate the well's surrounding area, additional risk mitigations were identified through HAZID workshops and implemented, such as creating gas drainage shafts, utilizing ATEX equipment and cold cutting tools for casings, tools, and organizing Rescue People Services. These elements and more aspects were elements of safety included in the project to better assure the success.
The project has several milestones, the first being the consolidation of the well surroundings using 33 cement pillar rings with a total diameter of 8m and depth of 32m. A gas relief column was necessary to ensure the gas infiltration was exhausted from the soil. Once the ring was formed around the well, the excavation commenced inside the ring, avoiding impact with the conductor pipe of the well. This activity posed notable HSSE challenges, requiring solutions derived from HAZID workshops based on evaluations of the various discipline teams and certified parties. Following the excavation, the planned casing remediation included cold cutting the casing using diamond encrusted equipment, due to the gas presence at the well area. Casing restoration was planned for use of bolts to reconnect the casings, thus preventing welding.
Simulation of Immiscible WAG Experiments Performed in Carbonate Rocks: The Impact of Heterogeneity on Hysteresis Phenomenon
Authors: Alnuaimi Latifa Obaid , Sohrabi Mehran , Aghabozorgi Shokoufeh , Alshmakhy Ahmed 
Published: December 2021

Abstract
Simulation of Water-Alternating-Gas (WAG) Experiments require precise estimation of hysteresis phenomenon in three-phase relative permeability. Most of the research available in the literature are focused on experiments performed on sandstone rocks and the study of carbonate rocks has attracted less attention. In this paper, a recently published hysteresis model by Heriot-Watt University (HWU) was used for simulation of WAG experiments conducted on mixed-wet homogenous carbonate rock.
In this study, we simulated immiscible WAG experiments, which were performed under reservoir conditions on mixed-wet carbonate reservoir rock extracted from Abu Dhabi field by using real reservoir fluids. Experiments are performed with different injection scenarios and at high IFT conditions. Then, the results of the coreflood experiments were history matched using 3RPSim to generate two-phase and three-phase relative permeability data. Finally, the hysteresis model suggested by Heriot-Watt University was used for the estimation of hysteresis in relative permeability data. The performance of the model was compared with the experimental data from sandstones to evaluate the impact of heterogeneity on hysteresis phenomenon.
It was shown that the available correlations for estimation of three-phase oil relative permeability fail to simulate the oil production during WAG experiments, while the modified Stone model suggested by HWU provided a better prediction. Overall, HWU hysteresis model improved the match for trapped gas saturation and pressure drop. The results show that the hysteresis effect is less dominant in the carbonate rock compared to the sandstone rock. The tracer test results show that the carbonate rock is more homogenous compared to sandstone rock. Therefore, the conclusion is that the hysteresis effect is negligible in homogenous systems.