bluuebunny/crossref_metadata_2025_split huggingface dataset:
Impact of Change in Mud Weight & Offset Well Injection Pressure on Cement Sheath Integrity; Case Study for UAE Offshore Field.
Authors: Elhassan Azza , Manga Patrick , Abdellatif Mohamed S. , Hamidzada Ahmedagha , Andrews Kerron , Takahiro Takahiro , Sherif M. 
Published: October 2023

Abstract
As drilling horizontal wells became more complex with multiple production drains from various reservoirs, zonal isolation has become a key challenge to be achieved. Many studies have shown the impact of change in mud weight during drilling activities on wellbore stability, without considering the consequences on the set cement. This case study will be focusing on drilling activities on offset wells, evaluating & exploring how mud weight changes can affect wellbore instability and damage the cement sheath despite the fact that the cement evaluation logs showed good results days after the cement job and before the mud weight reduction.
The wells being studied have been analyzed using Finite Element Analysis (FEA) modeling after the cement was set and exposed to a change in mud weight as well as being exposed to the offset injection well. FEA computer simulations have enabled this modelling to determine the optimal mechanical properties required for the cement slurries to withstand those load limits (pressure testing, pressure reduction due to change of mud weight or an increase of the pore pressure due to an offset injection well). After opening the window and drilling ahead through the production drain wellbore, the wells have the same tendency of instability and require an increase in mud weight to control the inflow.
This paper presents the impacts of the offset wells and the change of mud weight on the cement sheath failure in debonding, cracking, or sheath deterioration leading to gas channeling due to a micro annulus. The considered wells present the same behavior that has been highlighted above. The question to ask is why did a well that has been cemented and recorded a good cement bond fail to provide proper zonal isolation? The injection pressure of the offset well was evaluated and then used in the simulations, considering the conventional cement used during the primary cement job. The analysis has shown a complete failure of the cement integrity: cement debonding from the casing or from the formation; cement cracking and sheath failure.
The cement slurry with improved mechanical properties was employed for the study under the same pressure conditions from an offset well and mud weight change. The model results demonstrate that the new cement's ability to withstand stresses has improved on the wells cemented after this study.
The modelling effort presented in this paper allows for a barrier to be designed that has enhanced mechanical properties compared to the already placed barrier on the offset wells in the same field. Aside from improving the set cement mechanical properties, the mud weight change design has been improved in such a way that the mud weight must be anticipated, decreasing its impact on the barrier.
Challenges in Drilling and Completing Extended Reach Drilling Wells with Casing Design Optimized from Conventional Ones
Authors: Unnikrishnan N. K. , Alnuaimi M. , Al Suwaidi M. , Al Yamani S. , Bahumaish M. Jamal , Al Karbi H. , Salem G. , Al Ameri S. 
Published: October 2023

Abstract
Well was drilled in Al Nouf field with the objective to increase the sustainable production across Kharaib-2 formation. This paper presents the challenges faced in planning and drilling of subject well penetrating multiple reservoirs with only two casings. Later 4000ft horizontal hole was drilled in the same reservoir and completed with PPL lower completion.
Planning of this well commenced by meetings and collaboration with multiple disciplines such as Drilling, Integrity, technical center and Asset team with the common objective of drilling and completing a horizontal oil producer well in less duration and cost without compromising the integrity of the well. All the associated risks were highlighted and mitigated by proper planning and engineering analysis such as casing design, trajectory, collision risks, BHA, torque and drag and hydraulics. Management of change was issued and approved by all stake holders for deviating from the normal casing design as per company operation guidelines.
This ERD Oil Producer well is the first well in the field to successfully complete in only two casings sizes. This paper will explain the innovative and novel approach of mitigating the challenges faced while drilling a complex well of 7,400ft departure with two casings and have a horizontal section of 4000 ft with 8-1/2" drainage and completed it with 6-5/8" PPL lower completion. The main challenges were penetrating the total loss zone along with unconsolidated shallower formation in surface section and drilling the permeable reservoir with high mud weight OBM due to highly unstable shale formation above it. These challenges were immaculately mitigated with advanced engineering analysis and close supervision while execution. Results from this well have proven that having lower completion in ERD wells have significantly improved the well accessibility and well performance and enhanced the reservoir management and thereby reducing the field development cost without affecting the well integrity. This paper summarizes the practice and technology used to successfully drill the ERD well in artificial island with two casing sizes.
The challenges and its mitigation explained in this paper will support the idea to further drill and complete the well with minimum number of casing sizes. Thereby more number of wells can be drilled in less number of days and well cost.
Holistic Approach of Acid Stimulation Selection in Carbonate Fields for Productivity Enhancement
Authors: Sarsekov A. B. , Ryan A. , Kamaletdinov B. , Arali V. , Araque G. 
Published: October 2023

Abstract
Carbonate rocks constitute a significant portion of hydrocarbon reservoirs worldwide. Due to their unique geological deposition, carbonate formations have different ranges of heterogeneities such as mineralogies, permeabilities, fluid properties, fissures, natural fractures, and reservoir pressures. On top of their inherent heterogeneities, well operation activities such as drilling and well intervention can damage the formation. In the lower-permeability formations, a maximum reservoir contact (MRC) well is a preferred option to extract hydrocarbon from the reservoir. An MRC well involves specific challenges from the well completion perspective that eventually could impact the productivity.
Carbonate stimulation is a long-standing technique to increase productivity in carbonate formations. Stimulation treatment in general improves the hydrocarbon deliverability to the wellbore and eventually to surface. It also removes or, on some occasions, bypasses the damage in the wellbore. With a long horizontal well, more surface area must be stimulated; however, more surface area means there is more heterogeneity to overcome as well. This paper describes the importance of acid stimulation planning as well as modeling, which plays a vital role in effectiveness of acid stimulation job in horizontal wells with different MRC completion types and achieving the best results of productivity enhancement in carbonate fields.
Log-and-completion-based simulation software was used to model the formation heterogeneity in combination with well completion complexity. Different modeling scenarios based on well trajectory and completion design are simulated together with the reservoir heterogeneity such as different permeability, possible fissures, different reservoir pressures. Different acid systems are also simulated against these heterogeneities and complexities. The stimulation modeling results show that stimulation uncertainties arise when both completion complexity and reservoir heterogeneity are present.
A stimulation integrated workflow following the stimulation design workflow in the latest log-and-completion-based software is presented. Some case studies in UAE related to these challenges are presented with some key lessons learned. Some advanced carbonate acidizing technologies are implied in this observation to achieve the stimulation objectives.
i-Geo Sensing: An End-to-End Fracture Direct Diagnostic Platform
Authors: Van Pham Vuong , Dahaghi Amirmasoud Kalantari , Babakhani Aydin 
Published: October 2023

Abstract
Within the development of unconventional resources, especially in the United States, multi-stage hydraulic fracturing across multiple fields is adapted to become the best practice in the industry. In hydraulic fracturing, a complex fracture network is always initiated before the slurry fluid is pumped into the reservoir. Consequently, understanding this fracture network's geometry and its degree of complexity has been one of the forefronts of unconventional development. The industry has been conducting various methods to achieve this forefront, divided into three categories: direct near-wellbore (e.g., production/temperature logs, tracers, borehole imaging), direct far-field (e.g., micro-seismic fracture mapping), and indirect modeling (net pressure method). Unfortunately, none of these methods provide direct and dynamic information about the hydraulic fracture network.
In this study, a novel integration of both hardware (namely, the Smart Microchip Proppants, abbreviated as SMPs) and software (namely, the i-Geo Sensing) is conducted to address the "indirect" drawback of current fracture diagnostic techniques and practicalize the power of modern Deep Learning in semi real-time fracture mapping. The SMPs are explicitly designed to be injected directly into the reservoir along with the conventional proppants. This paper focuses on the transmitted smart microchip proppants data in semi-real time. The i-Geo Sensing is integrated between three core modules: the unsupervised, the supervised, and the connector. The unsupervised module digests the transmissible signal from the SMPs, performs necessary pre-processing, and recognizes prospective fractures. The supervised module receives the result from the unsupervised module, combines with the support from the data generator module, flow-back/production data, and eventually predicts the most reasonable realizations of the hydraulic fracture network.
The i-Geo Sensing's capability is tested using a case study with the pre-defined hydraulic fracture geometry. Results from the case study indicate the robustness of the supervised module under unknown loss of data transmission from the SMPs (2-5% decrease in accuracy) and consistent improvements of accuracy between 9-25% in fracture diagnostic from the unsupervised module to the supervised module.
Cross Functional Improvements in Modelling Complex Carbonate Reservoirs
Authors: Wahbah S. , Almheiri A. , Hattori T. , Alhosani F. , Farmer R. , Gacem M. T. 
Published: October 2023

Abstract
Geological Modelling (GM) of heterogeneous carbonates can be challenging to history match with actual reservoir performance. Reservoir heterogeneities that present challenges to history match production include High Permeability Streaks (HPS), Stromatoporoid layers (STR), Fractured Dolomites (FD) and in this reservoir, extensive porosity-deteriorated bitumen-affected volumes. Local experience and knowledge help address model limitations and inconsistencies, and correlating diverse data types is critical to bridge gaps when uncertainties compound: this case study details multi-disciplinary improvements of such GM.
3D seismic was reprocessed to improve signal-to-noise ratio (SNR), fault interpretation and AVO/AVAz and seismic attributes, stochastic inversion, and rock physics analysis was used to improve facies and porosity modelling, facilitated by a strong, three-way relationship between Acoustic Impedance, porosity, and STR layers. In addition, newer horizontal wells with wellbore images helped improve the understanding and distribution of STR and bitumen presence and validated the updated seismic fault interpretation. 3D seismic inversion identified a top bitumen surface scenario that was supported in well observations. Refinement of the stratigraphic framework, zonation and layering captured heterogeneities including vertical and lateral lithofacies distributions and sequence boundaries, and an updated rock typing (RT) scheme characterized reservoir heterogeneities (HPS & Bitumen presence).
Updated Saturation Height Function (SHF) and Free Water Level assumptions accommodated the new structure and RT scheme. Multiple models were tested to characterize saturation models from Pc curves and statistical analysis of saturation residuals and hydrocarbon pore thickness was used to assess and rank model performance. The selected SHF model was based on model efficacy on multiple scales from field, domain, wells, layers and by RT.
Integrating multi-disciplinary data types to resolve reservoir challenges is a crucial aspect to deliver fit for purpose geological and dynamic models in mature fields. This case study illustrates the value of merging geophysics, stratigraphic, lithologic and petrophysical data and analysis to update model properties and performance and identify and address uncertainties.
Well Life Extension Via Casing Corrosion Control
Authors: Yugay A. , Elsabbagh Dr. Fady , Maldonado J. N. H. , Yang H. , Vorozhikhin S. , Zhukin A. , Girgis F. , Alkarbi M. A. 
Published: October 2023

Abstract
Well casings are the main element of the well secondary barrier envelope. Ultimate well life is defined by the condition of the casings (since those are not replaceable comparing to tubing’s if cemented to surface). Casings are made from carbon steel and gets corroded if not properly protected. Cathodic protection addresses the exposure of the casings to the external corrosive environment but doesn’t help in the double casing ("shielded") area.
Due to the fact that complete fluid displacement with absolutely clean cement slurry behind the casing cannot be guaranteed and there is always a risk of contamination with the fluids pumped ahead (which gets trapped in the annulus and can create corrosive environment in stagnant conditions), the proposed solution assumes usage of corrosion control additives in the fluids pumped prior to the cement slurry to mitigate corrosion. Those includes oxygen scavenger, corrosion inhibitor and biocides.
Review of the corrosion logs confirmed there is a threat that needs to be properly addressed. The review was done for the double casing area of the wells that have both inner and outer casing evaluated by corrosion logs. The inner casing was evaluated by the conventional azimuthal ultrasonic or magnetic flux leakage logs, the outer casing was evaluated by the electromagnetic Eddy current based log. It was several cases observed with outer casing corrosion on the inner string while the outer string wasn’t corroded. That means that the casing got corroded externally due to the corrosion environment created in between two casings. Review of the cement logs across the same are shows lack of cement isolation and demonstrates contamination with other fluids pumped ahead of the cement. Those may include drilling mud, low-viscous pill, cement spacer. Lab analysis of the samples of the water used to prepare those fluids shows high oxygen content, comparing to the standard safe operating limits. Oxygen can act as a trigger for the corrosion and also can act as a consumable of the corrosion reaction. Keeping it under control may not only prevent corrosion, but also reduce it in case it still occurs.
This study proves the threat of the casing corrosion due to imperfect cement isolation based on the actual events. Proposed solution of the corrosion control via chemical treatment of the fluids pumped ahead of the cement slurry is dramatically cheap comparing to the overall well budget but has a strong direct positive impact on the ultimate well life. Recommended to be used by all operators complying to well double barrier policy.
Integrated Gas Asset Optimization System (IGAS) - Developing an Integrated Production Efficiency Optimization Tool Across Upstream and Downstream Process Lifecycles for a Gas Condensate Asset in Abu Dhabi
Authors: Al Maazmi J. , Mabrook M. , Al Badi M. , Al Bairaq A. , Mogensen K. , Al Suwaidi E. , Al Saeedi A. , Al Hareithi F. , Sivanandam S. , Al Yaaqoubi N. , Al Mheiri E. 
Published: October 2023

Abstract
IGAS is a project that aims to develop a digital network optimization model capturing the complete gas life-cycle of Reservoir A from its Upstream through the Downstream process flow. This submission focuses on the modeling efforts and the preliminary implementation of the model in a field trial to generate optimized production scenarios aimed to maximize condensate production in a reservoir developed under gas recycle strategy to form the basis for the development of an AI optimization tool.
IGAS model was built using commercially available solutions to integrate the upstream and downstream models. Model development was straight forward with commercial well performance and network modelling tools combined with process workflow simulators to develop upstream and downstream models, respectively. Those were assimilated in a single tool using an interconnection platform to facilitate integration of workflows. Post model integration, a field trial was conducted to validate the model’s accuracy in generating condensate maximization scenarios.
IGAS field trial was conducted over a period of 10 weeks. A scenario was generated in accordance with the expected well availability for duration of the field trial. Post field trial, two primary observations were made: An Adherence Score metric was created, which calculates how well the IGAS scenario was followed considering each well’s CGR and suggested IGAS rate. A direct correlation was observed between Condensate production and Adherence Score objective function, indicating that the more IGAS scenario is adhered to, the more condensate is produced.Condensate history matching exercise was conducted for the trial period duration, which observed an average error of 1.72% (model vs actual production). This was followed with an optimized scenario generated for each day of the trial period (actual wet gas production for given day was set as constraint to ensure fair comparison) in order to quantify the potential condensate production. This exercise observed an average additional condensate production of 2.2%, which could have been produced if the IGAS scenario was adhered to. Unlocking such value would require the installation of well choke actuators to facilitate instantaneous changes to the chokes.
IGAS serves a great example of the potential value that can be unlocked with modern day IAM (integrated asset model) solutions. More importantly, it sheds light to the importance of developing unmanned field operations (well choke actuators in specific), which maximizes the use of IAM solutions such as IGAS enabling instant implementation of suggested scenarios.
Numerical Investigation of Acid Stimulation Process in Carbonate Rocks with Heterogeneous Mineral Distributions
Authors: Jia Cunqi , Alkaabi Saif , Hu Jinchuan , Sepehrnoori Kamy 
Published: October 2023

AbstractAcid stimulation is a common well stimulation technique for the effective development of carbonate reservoirs, in which the acid solution is utilized under the formation fracture pressure to increase formation permeability while bypassing damaged domains around the wellbore. This study is motivated to evaluate the effect of mineral heterogeneity on acidizing efficiency in carbonate rocks. The two-scale continuum model is employed to describe the mass, momentum, and energy change during the acid stimulation process. In particular, the solid phase mass conservation equation is extended to consider mineral compositions, including reactive minerals of calcite and dolomite and non-reactive minerals of clay and quartz.Results indicate that mineral heterogeneity can affect both the acid consumption efficiency to achieve a breakthrough and the optimum acid injection rate corresponding to the minimum pore volume to breakthrough. The acid stimulation curve is more sensitive to the content of reactive components. More acid solution is needed to stimulate the core sample with a less reactive component of dolomite. The optimum acid injection rate increases as calcite content increases. When the reactive mineral distribution is not continuous, such as vertical or layered distribution, the acid stimulation curve is complicated by the competing reactions between reactive minerals.
Turning Acid Treatments from Failure to Success Using Polymer-Free Single-Phase Delayed Acid: A Case Study of Complex Horizontal Well in Dolomitic Formation, UAE
Authors: Zakaria A. , Ruiz C. Sirlupu , Singh A. , Mahabir R. 
Published: October 2023

Abstract
Horizontal wells with long laterals and Inflow Control Device (ICD) completion drilled from artificial islands are adopted in an offshore field, UAE to boost hydrocarbon production from high-temperature Arab formation. High-temperature conditions, long lateral, heterogenous reservoir, ICD completion, and dolomitic formation provides harsh environment for a successful acid stimulation treatment. Previous interventions with regular 28 wt% HCl and conventional emulsified acid were conducted in one of these oil horizontal wells. Both acid treatments failed and resulted into no incremental production. The horizontal well was completed across a long lateral of 5,200 ft with 4 ½ in. liner equipped with ICD system with a high bottom hole temperature of 300°F, permeability range of 0.3 to 40 md, and average porosity of 15%. In this paper, we will discuss how the application of the new polymer-free, single-phase delayed acid fluid (PFDA) technology unlocks the full production potential of Arab formation.
Extensive laboratory testing including diffusivity testing, coreflow testing, and computed tomography scanning was conducted to evaluate the performance of the PFDA against regular HCl and emulsified acid. These tests proved that the use of PFDA would enhance the acid penetration in the dolomitic formation due to the retarded rate of reaction, maximizing reservoir contact. The tests also proved that 20% acid strength would be effective to create long dominant wormhole, bringing advantage to reduce corrosion package compared to the previous treatment using regular 28% HCl
The low friction of the new polymer-free, single-phase delayed acid (PFDA) enabled high pumping rate through Inflow Control Devices (ICD) completion during the entire treatment, which was previously a challenge due to high viscosity of emulsified acid. The PFDA was combined with a viscoelastic surfactant-based diverter to maximize lateral coverage in the heterogenous reservoirs. Software modelling was coupled with the extensive testing and the PFDA fluid technology to optimize job design, volumes, pumping rates, and diversion strategy. The integrated approach yields unprecedent stimulation success.
Post treatment analysis showed that the PFDA boosted the production by more than 1000 BOPD (140%) compared to no incremental production from previous acid stimulation treatments with conventional emulsified acid. The use of PFDA enabled high pumping rates up to 20 bpm compared to 12 bpm for emulsified acid, reduced the mixing time by 16 hours, and saved on associated cost and time.
The introduction of the new PFDA provides the industry a revolutionary fluid technology to unlock the full production potential of Arab carbonate formation. Moreover, the polymer-free, single-phase delayed acid simplifies operations, eliminates the need for diesel phase and associated HSE concerns, and reduces carbon footprints.