bluuebunny/crossref_metadata_2025 huggingface dataset:
A Comprehensive Analysis of Filter Cake Breakers for Non-Aqueous Drilling Fluids
Authors: Stamer K. , Baltaeva M. , Orlov M. , Wagle V.
Published: February 2024

Non-aqueous drilling fluids (NADF) have become widely used due to their ability to provide failure-free drilling in difficult conditions. During the drilling, the filter cake is being built on the wall of the borehole providing the integrity of the wellbore and preventing formation damage. However, filter cake can cause long-term bringing-in of a well and an increased value of the drawdown required for inflow stimulation. Hence, the filter cake has to be successfully removed in order to maximize the well's productivity. The goal of the research is to provide a comprehensive analysis of various formulations used for NADF filter cake removal.

NADF is typically formulated using oil as a continuous phase, brine as a dispersed phase, emulsifiers, wetting agents, and gellants. Depending on the reservoir, the filter cake may have a complex structure due to the particles’ intermixing with the emulsion to create the internal and external layers. Destruction of this system is an intricate task, particularly in horizontal and multilateral wells. An effective breaker must be able to separate the mud into component phases and simultaneously dissolve the weighting agents. The design of an effective treatment requires accounting for the mud composition, formation type, downhole conditions, and type of a completion. The variety of available solutions as well as their advantages and limitations are described in this article.

The results of the research demonstrate that state-of-the-art systems and technologies can be divided into several groups depending on the number of stages and the required alteration of the rock wettability. To dissolve the external filter cake built by the hydrophobic weighting materials the chelating reagents, acids or acid precursors are commonly utilized. An internal filter cake formed by the emulsion drops and emulsion blockage in the damaged zone can be removed by solvents, mutual solvents, de-emulsifiers or microemulsions. Modern eco-friendly technologies as well as multifunctional thermochemical fluids used for removing the barite filter cakes are also highlighted in the publication. It is shown that many factors affect the filter cake removal efficiency, including mud oil-water ratio, types of solids present and their concentration, salinity, and temperature. Furthermore, a preliminary assessment of breakers’ performance should be performed in a laboratory while considering the individual characteristics of each well.

Although many formulations have been introduced to remove barite filter cake in NADF, the need for a low-cost, compatible, and efficient breaker still prevails. Based on the research findings, a new thoroughly selected composition of chelates, surfactants, and additional reagents as a breaker with high de-emulsifying properties, and barite-dissolving ability is expected to be developed to break down the filter cake after completion of drilling with NADF.
Effect of CO2 Chemical Reactions on Rock Pore Surface Morphology – A Laboratory Study
Authors: Singer Gabriela , Ma S. Mark , Chen Songhua
Published: February 2024

CO2 capture and subsurface sequestration (CCS) is a viable solution to reduce the greenhouse gas effect on global warming. It is known that CO2 in water chemically reacts with rocks during the process of CCS (injection, migration, plume, and long-term storage). The objective of this study is to better understand the dynamics of this interaction, and to develop measurements capable of monitoring changes of rock properties during CCS.

As changes in rock properties originate from chemical reactions between pore-surface minerals and CO2, characterizing changes in pore-surface texture and geometry is essential for predicting subsequent changes of other rock properties relevant for CCS. As such, the methods used in this laboratory study include laser scanning confocal microscopy (LSCM) for measuring pore-surface roughness, Brunauer-Emmett-Teller (BET) adsorption isotherms for measuring the specific surface area, and nuclear magnetic resonance (NMR) relaxation for measuring pore-size, pore-connectivity, and surface-relaxivity (a function of wettability and fluid-surface interactions).

In this study, five brine-saturated carbonate rocks (including three outcrops and two reservoir rocks) were exposed to supercritical CO2 (scCO2) under various ageing conditions. Specifically, we exposed the carbonate rocks to scCO2 under increasing pressure, temperature, and salinity, and measured LSCM, BET, and NMR after each of the total five ageing steps. By comparing with the initial non-ageing measurements, data indicate that the scCO2 exposure increases both surface-relaxivity and surface-roughness, particularly for the reservoir rocks. At the final step of ageing, the scCO2 exposure increases both pore-size and pore-connectivity for the reservoir rocks and some outcrops.

Our findings may have direct impacts on planning and executing CCS projects, especially in carbonates. Changes in pore surface roughness and wettability can directly affect CO2 injection because it affects the reactive surface of the pores. Once significant surface erosion occurs, other macroscopic properties may change as well, as observed from the increase in pore connectivity in certain cases. Dissolution and precipitation change the pore-size and connectivity, thereby capillary pressure and permeability, which may also affect caprock's integrity. Our study shows that quantifying the changes caused by CO2 chemical reactions with rock minerals is crucial for CCS projects, including site selection and storage capacity assessment. Further, this study shows that NMR could be a valuable downhole tool to capture and monitor these changes, such as assessing changes of rock properties due to CO2-rock chemical reactions and contributing in validating dynamic chemical reaction models and help to adjust for prediction models.
OBM Resistivity Imaging in Formations with Wide Resistivity Range, Multi-Frequencies Acquisition to Identify Features of Different Characteristics
Authors: Kader Ramy Abd El , Khamry Ayman Al , Woldeamanuel Mandefro B , Gouda Mohamed
Published: February 2024

Several challenges were encountered to obtain good quality of high-resolution resistivity images in oil-based mud (OBM) borehole environment. Technology development incorporated innovative designs of multi-arm, multi-frequency resistivity imaging pads to mitigate some of these challenges. This article will demonstrate the achieved benefits of deploying two OBM wireline (WL) resistivity images in addition to ultrasonic imager, in a large and intermediate vertical borehole through mixed lithologies with wide range of Formations resistivities and to provide recommendations for future deployments.

Pre-planning is emphasized for achieving good results; expected lithologies, resistivity ranges, OBM components, etc. Accordingly, frequencies selection and required logging passes can be advised. During image acquisition, raw data processing takes place instantaneously to maintain real-time quality control and perform interactive changes as required for logging optimization. Customized composite plots are produced to compare between processed images from different frequencies to visualize the variable definition of borehole features between frequencies in ascending order. At this stage, dielectric effects on higher frequencies can be observed clearly when the Formation's resistivity range comes out of limits for these frequencies.

In different Formations resistivity ranges, Low-Resistivity-Low-Contrast (LRLC), medium and high, it was proven that implementing multiple frequencies from OBM resistivity imaging technologies significantly reduce the probability of missing the definition of fine features such as thin-bedding sequences or natural fractures those existed in Formations of wide resistivity range (0.2 ~ 1500 ohm.m). Multiple frequencies from OBM resistivity imagers plus one from the ultrasonic imager were processed, compiled and analyzed to conclude that using of multiple frequencies is far superior than single-frequency OBM resistivity imager in similar environment, confirming the need to combine technologies to cover wider range of measurement specifications and to urge the industry towards the innovation of a single new technology that incorporates wider range and number of frequencies covering the measurement range and required environmental corrections in one platform.

Eventually, OBM resistivity imagers of multiple frequencies deployment is becoming more proven approach after studying this case, and way important to achieve the deployment objective of high-resolution borehole imaging service(s) in OBM borehole environment. Future technology development is intended to correct for measurement artifact.
Monitoring and Optimizing Mud Motor Efficiency and Degradation in Real Time
Authors: Zhang Z. , Shen Y. , Chen W. , Ba S. , Scarioni F. , Vasquez D. , Belov D. , Converset J.
Published: February 2024

Mud motors are widely used in drilling operations to boost up drilling energy input and increase rate of penetration. It is essential to monitor the efficiency of the mud motor during drilling to ensure it being operated at optimum status. Besides, it is critical to identify the level of mud motor degradation and the trend in real time so that timely pull out of hole advise can be made before developing into a severe failure. This paper presents a real time solution to optimize mud motor efficiency and monitor its degradation based on streamed surface and downhole data, derived mud motor characteristics from modeling, and extracted insights from data analytics.

To compute mud motor efficiency and degradation in real time, it leverages surface operation parameters and average downhole rotational speed. By incorporating mud motor characteristic curve, we compute the mud motor torque, RPM, power input and output during operation. Then the real time efficiency and degradation of the mud motor is estimated. In the meantime, data analytics methods are exploited to identify the trend of the mud motor degradation and detect its critical change point, which is used to provide insights of the operation. In addition, a database has been established by applying the same computation on thousands of fields runs, which covers various hole sizes, bit types, mud motor models, locations, formations. The thresholds of mud motor efficiency and degradation were extracted statistically from the failed motor runs. In the real time application, those thresholds are adapted to evaluate risk levels based on the real time mud motor efficiency and degradation level.

The solution helps improve drilling performance by comparing the real time mud motor efficiency with selected offset runs with similar applications. Based on offset mud motor failure cases, the solution provides quantified real time degradation risk index which provides opportunities to identify signs of mud motor degradations and to intervene in early stage to prevent it from developing into catastrophic event. The solution has been deployed to the field locations and serves as part of the mud motor interpretation answer product in real time monitoring standard workflow.

Monitoring the efficiency and degradation of a mud motor is a not an easy task. In most cases, when the rubber chunks are found on the shaker, the mud motor is already severely degraded, and the performance has been compromised for long time. This paper presents a unique solution to monitor mud motor efficiency and degradation in real time and aims to capture the issue in early stage. It combines domain knowledge, data analytics, offset well analysis to derive real time solution to manage mud motor efficiency and degradation.
Near-Bit, Real-Time Measurements from an Innovative Ultra-Deep Electromagnetic Tool for Proactive Geosteering in Horizontal Wells
Authors: Wu H. , Clegg N. , Duriez A. , Ma J. , Wu D. , Bikchandaev E. , Lozinsky C. , Bittar M.
Published: February 2024

In some reservoirs, where optimum well placement requires that a well be placed close to a formation or fluid boundary, changes in the position of the boundary need to be identified early to allow prompt correction of the well path, preventing the well from intersecting the boundary and incurring a costly side-track. Even if the angle between the boundary and the well is only a few degrees, the distance between them can change rapidly. If a tool measure point is far from the bit, a reservoir exit may occur before corrective action can be taken.

An innovative, ultra-deep electromagnetic (EM) design, integrated with the rotary steerable system, places a sensor location 9 ft behind the bit. The novel system enables near-bit, ultra-deep azimuthal resistivity (UDAR) measurements, providing inversion results for the surrounding structure much earlier than existing ultra-deep EM systems. The new UDAR tool achieves an inversion detection range of over 100 ft, with the sensor measure point very close to the bit. This allows for earlier identification of changes in formation or fluid dip, facilitating proactive well-placement steering decisions.

This paper investigates how the depth of detection of formation boundaries, the relative angle between the boundary and the wellbore, and the sensor measure point affect the ability to avoid hazards during well placement operations. There are common limits on the maximum allowable dog-leg severity (DLS) due to the need for later passage of the completion assembly through the wellbore. Early identification of any change in the dip of a boundary is therefore critical. The closer the sensor measure point is to the bit, the quicker this trend can be identified and the required remedial action taken, within the prevailing DLS constraints.

In summary, the real-time UDAR inversion of the new system enables much earlier geosteering decisions than existing technologies, resulting in a significant advance in well-placement technology. Reducing or eliminating geosteering risks helps reduce overall well time, maximize the value of each well, and improve the overall efficiency of a field development.
Achieving Operational Excellence Using an Interactive Drilling Time Analysis and Benchmarking Methods
Authors: Amer Mustafa , Radhwi Asem , Othman Amr
Published: February 2024

OBJECTIVE / SCOPE

Performance improvement to reduce the cost is a common goal for the industry, there are many initiatives and processes now in place, applying different techniques. Most of these techniques are dependent on operational time-distribution analysis, to benchmark current performance and predict future performance, while identifying improvement opportunities. An objective, standard, yet flexible tool is required to support these different approaches. Authors will share their experience of developing a method and tool that serves this purpose.

METHODS, PROCEDURES, PROCESS

The tool provides an environment that enables users perform different types of analytics: descriptive, predictive and prescriptive on the operational time-distribution data. The data sources in this environment are integrated seamlessly to facilitate comparative analyses on many aspects of drilling performance providing the following: Compare actual performance with the planAllow pre-, post-, and active-execution performance analysisIdentify current performance limitations and potential improvementBenchmark performance for different teams, contractors and service providersInvestigate lost time incidents; evaluate their impact; and discover root causes behind itProduce an automated Ultimate Drilling Curve and build realistic time estimates for future wells

RESULTS, OBSERVATIONS, CONCLUSIONS

The proposed system architecture contains four main modules, which provide the aforementioned functionalities, through comprehensive interactive tools to facilitate analysis of drilling time at different levels of granularity. These modules are: Wells Similarity Identification, filtration, and Selection moduleGeneral Time Distribution Comparison moduleProgress Charts (time versus depth) Analysis moduleLearning Curve Evaluation module

The proposed system functionality will be introduced through this paper in addition to a methodology to utilize these tools to perform variety of comprehensive performance analysis studies.

NOVEL/ADDITIVE INFORMATION

The proposed system is an integrated interactive platform for different user groups to run sophisticated performance analytics and studies efficiently and effectively without being limited to specific scenarios or data types.
The Benefit of In-Bit Sensing for Efficient Drilling of Deep Reach Lateral Wells in HFTO Prone Interbedded Abrasive Lithologies in North America Land
Authors: Hanafy A. , Kueck A. , Pauli A. , Huang X. , Bomidi J.
Published: February 2024

Reaching the pay zone of deep lateral wells requires several bits due to vibration-prone interbedded abrasive lithologies in North America Land. Excessive wear of cutters combined with extreme torque fluctuations results in reduced ROP and premature failures of BHA tools. Early POOH leads to 24 h to 48 h of non-productive time due to BHA tripping. This puts enormous economic pressure on these challenging pay zones. This paper presents a detailed analysis of downhole and in-bit sensing data to increase the operational stability window enabling enhanced bit durability and smoother drilling conditions for economic drilling of long lateral wells.

The proposed bit's operation optimization framework is based on a detailed analysis of in-bit high-frequency gyroscope and accelerometer data correlated to vibration and Gamma-ray measurements of MWD and LWD tools. The data analysis reveals High-Frequency Torsional Oscillation (HFTO) prone formations and HFTO frequencies, amplitudes and durations while drilling in lithologies with different rock strengths. The results are compared to lab tests drilling on a full-scale drilling rig using representative rock cores under high confining pressure. The lab measurements are used to model the performance of drill bits accurately and develop best practices for operations. An operational stability map and a drilling guideline have been built and communicated with the region to enable longer reach wells and stable drilling.

The data analysis shows a correlation between the lithological shaleness factor and the BHA sensitivity to excite HFTO among other vibrations. The higher the shale content of the gamma ray track the lower the probability of triggering HFTO. These findings are reflected in the lab while drilling interbedded cores at high confining pressure. The data are used to calibrate bit models for design optimization. The application of drilling guidelines on operating 9 bits resulted in a total savings of $500K per well and reduced the non-productive tripping time by 4 days. Guided drilling practices increased the drilled footage per bit by 50%, and reached the same dull state as previous operations. Control of HFTO and vibrations reduced early failures of BHA tools enabling longer intervals and less unnecessary trips.

The lack of wire line logging in extended reach lateral wells limits the understanding of targeted formations. This framework enables deeper formation insights that unlock the optimization of performant drill bits. The adoption of this practice promises longer footage per bit, less downhole vibrational issues, and efficient completion of interbedded abrasive lithologies in the future.
Deep Learning Real-Time Bit-Wear Model Approves to be Robust and Transferable in Hard Drilling Applications
Authors: Zhan Guodong David , Aljohar Abdulwahab , Qahtani Yazeed , Huang Xu , Luu Trieu Phat , Furlong Ted , Bomidi John
Published: February 2024

In a previous study, we reported the development of a bit-agnostic AI deep learning wear model and showed the successful real-time deployments in multiple field bit runs. To test AI/DL model robustness and transformability, we extended the AI/DL model to another similar hard drilling application with different hole sizes, BHAs, bit designs, and lithology. The model robustness is successfully tested using a smaller dataset of subsurface logging and surface drilling data.

AI/DL bit wear model employs an unsupervised bi-directional Long short-term Memory-based Variational Autoencoder (biLSTM-VAE) to project raw drilling and formation logging data into a lower-dimensional latent space. XGboost classifier is used to predict real-time bit-wear in the pre-trained latent space. Physics-based input feature engineering is conducted to extract meaningful information from the raw data. To test the model robustness when transferring to a different drilling application, only Gamma logging data and a smaller offset training dataset is applied. The deep neural network was trained in an unsupervised manner and the bit-wear estimation is an end-to-end process.

AI/DL wear model was trained on twenty offset bit runs. To test the model robustness, different hole sizes and BHAs were selected in addition to bit design and lithology changes. Unsupervised training results show biLSTM-VAE model successfully extracted bit wear features and clustered bit states in the latent space. Bit wear estimation using XGboost matches with the field results for the test dataset. In the previous real-time study, Gamma ray, density and porosity loggings were used in AI/DL model for downhole formation interpretation. The model robustness test in this study demonstrates the AI/DL model can be applied to applications with only Gamma data. BHA feature testing suggests separate AI/DL models need to be trained for RSS and motorized RSS systems.

AI model robustness and transformability is crucial for the success of AI model field deployments. The model robustness test in this study shows encoding drilling data into a lower dimensional space through unsupervised learnings could improve the model robustness and overcome offset training data quality issue. AI/DL results suggest exploratory data analysis of input drilling features such as BHAs and formation loggings is important for the model accuracy.
A Step Change; Achieving Excellence in Optimizations and Exceeding Global Top Quartile in a Brown Field
Authors: Al-Hajri A. , Al Shukaili G. T. , Urdaneta G. , Al Adi F. , Kaabi M. , Al-Kindi S. S. , Kiyumi W.
Published: February 2024

This SPE paper provides valuable insights into a brown field facing significant challenges, including a sharp decline rate resulting from nearly exhausted optimization opportunities, a rapid increase in water cut, and high deferment due to frequent pump failures. However, through a well-coordinated and multidisciplinary approach, the field managed to achieve a remarkable 15% optimization gain, surpassing the global top quartile, and improved the decline rate from 11% in 2020 to -7.7% in 2022.

The success of the field's transformation was driven by an integrated field review, which uncovered overlooked opportunities through extensive participation from various disciplines. Key to this success was the conversion project, which involved changing Beam pump (BP) or Progressing Cavity Pump (PCP) to Electrical Submersible Pump (ESP) and BP to Long Stroke Pumping Unit (LSU), significantly boosting production and enabling the reopening of Closed-In Wells (CIWs) that greatly benefited from these conversions. Furthermore, the implementation of other identified opportunities such as Water Shut-off (WSO), stimulation, Proactive Pump Replacement (PPR), and pump upsize resulted in the execution of a total of 82 activities in 2021 and 2022, all accomplished without encountering H2S issues.

The maturation of these activities yielded impressive results in terms of decline rate improvement, optimization gain, and deferment reduction. The field's decline rate notably improved from around 11% in 2020 to -7.7% in 2022. This achievement can be attributed to the substantial increase in optimization gains from 3% to 15.3%, and a significant decrease of 68% in unscheduled subsurface deferment. The conversion project, particularly the shift to ESP, significantly increased net oil production by enabling higher gross production, contributing to the remarkable optimization gain. The Long-Stroke Pumping Unit conversion also demonstrated a remarkable 40% energy saving.

The implementation of the conversion project also positively impacted deferment by significantly reducing pump failures, as evident from the drop in the failure index from 30% in 2020 to 18.8% in 2022. Despite the overall improvements in various aspects, it is essential to acknowledge that water production increased due to the higher gross production resulting from the ESP conversions.

The paper highlights the significance of this brown field's unprecedented achievement, surpassing the global top quartile in optimizations despite almost depleted opportunities. It showcases how thinking outside the box and employing engineering judgment can lead to a remarkable transformation in a matured field. The success story demonstrates how the spark of innovation evolved into a flame that far exceeded global top quartile benchmarks, making this field one of the most important and noteworthy in the cluster.
Prevention of Stuck Pipe Events and Robust Real-Time Identification of Root Cause Using Physics Based Models in Combination with Bayesian Network Models
Authors: Yi Michael , Ashok Pradeepkumar , Behounek Michael , White Spencer , Peroyea Trey , Thetford Taylor , Hickin Gary , Pearce Julie
Published: February 2024

When stuck pipe incidents happen, they can drastically increase the cost of a well. Although much progress has been made in stuck pipe prevention it has not been eliminated. Therefore, there is an ever increasing need to be able to automatically estimate the potential for a stuck pipe event so that preventative measures can be taken. Additionally, when the pipe does get stuck, if the reason can be determined quickly, non-productive time (NPT) can be substantially reduced. The objective here is to combine physics-based models with Bayesian networks to better diagnose drilling events and prevent stuck pipe NPT.

The approach focuses on identifying three main symptoms: pack off, overpull and off-bottom rotational drag. These are detected through three separate ML models, which in this case are primarily Bayesian belief networks. Inputs to these ML models require the use of a real-time physics-based torque and drag model as well as a real-time hydraulics model. These models require contextual data which is automatically routed to the rig platform. The features used in the ML models were arrived at after a careful detailed study of a large dataset of previous stuck pipe incidents.

The dataset used for building the models were from wells in North American and Middle East land operations, and North Sea offshore operations. This helped build a generalized model which is expected to be applicable irrespective of the geographic location of the well. The contextual data that is required consists of the survey data, the bottom hole assembly information, mud properties, and casing information. While it is uncommon for such data to be generally available at the rig site for real-time analysis, the team deployed novel automated data transfer mechanisms to enable real-time data transfer in all three operation locations. Tracking the data continuously also provided a means to determine when a stuck pipe incident occurred in real-time, and using data up until the current time, the algorithm probabilistically estimated the cause. This can allow for quick remedial action, which in turn leads to reduced NPT. The approach has now been deployed in the field after validations on historical datasets.

This is the first time a combination ML and physics-based approach to stuck pipe detection has been deployed at a rig site. The models are not black boxes and provide prescriptive recommendations on measures to take to avoid stuck pipes. If a pipe does get stuck, the user is provided with immediate notification of likely root cause. The paper provides details on the models used and is expected to significantly improve stuck pipe prevention in the industry.
Research and Application of Completion and Workover Fluid Technology in Heavy Oil Reservoir in Ecuador
Authors: Baojun Li , Pingya Luo , Xiangyang Zhao , Long Chen
Published: February 2024

This paper aims at the problems such as emulsification and thickening of crude oil mixed with working fluid, organic matter precipitation, crystallization and precipitation of high density completion fluid under formation conditions, and solid damage of oil formation caused by working fluid in Ecuador completion construction. Through the physical property analysis of formation fluids in Ecuador, as well as the mechanism analysis of emulsification and precipitation, high efficiency mutual solvent, reverse emulsifier and no solid phase aggravating agent are studied in the laboratory, and the solid phase free, high density, low damage and low corrosion completion and workover liquid system and process technology suitable for Ecuador's heavy oil reservoir are formed, and the evaluation and performance optimization are carried out. The density of the working fluid is 1.10-1.55g/cm3, the pH value is 6-8, the API filtration loss is 10.5mL/30min, the core penetration damage rate is 8.7%, the clay anti-swelling rate is 97.9%, and the corrosion rate is 0.039mm/a. Scale inhibition capacity (turbidity value after mixing with 5000mL/L NaHCO3 solution) 6.98NTU. According to different reservoir flow properties and construction conditions, compatibility control technology is studied, completion fluid formulations in different blocks and working conditions are tested, and field tests are carried out.10 field tests are completed in Parahuacu, Tambococha and other blocks, and the construction work is smooth and good results are achieved.
The Application of Foam and Gel Compositions to Control Gas Inflow in Production Wells: From Laboratory Studies to Injection
Authors: Belovus P. N. , Penigin A. V. , Shirobokov A. V. , Oleynik A. A. , Minnebaev B. R. , Saifullin E. R. , Varfolomeev M. A.
Published: February 2024

The formation of gas cones and the formation of local breakthroughs is a serious complication in the development of thin oil rims with gas caps. It leads to losses in oil production due to the failure of pumping equipment or choking of a productive interval located behind the gas breakthrough interval. With intensive gas breakthrough, the feasible well life is significantly reduced and, as a result, oil recovery factor is hindered.

To plan gas inflow reduction measures, it is necessary to conduct special laboratory studies to remove the main uncertainties that affect the success and efficiency. These include physical characteristics of the injection agent under operating conditions, its ability to block the unwanted phase, the selectivity of the treatment, the required injection gradients, and agent shear gradients.

Depending on the characteristics of the reservoir and formation fluids, various types of chemical compositions are used to alleviate or prevent gas breakthrough: foams, foam polymers, foam gels, gels, microcements.
Capillary String Deployment Methodology for Tight HPHT Gas Wells Deliquification
Authors: Kalwar Ghulam Murtaza , Yami Ali M , Alomran Ali A , Kaleem Abdullah
Published: February 2024

De-liquification method utilization has been investigated as a possible solution in sweet and sour gas wells, which suffer from liquid loading issues. There are limited options available to deploy de-liquification technologies in deep, unconsolidated, high temperatures, and in for specific completion designs. This paper discusses the screening of a range of methods and selection of a robust option to deploy downhole injection treatment facilities for the continuous foam.

The technical feasibility of a range of downhole foam injection installation methods, while maintaining minimum barriers, has been assessed. The continuous deployment of downhole foam injection is much more efficient and cost effective compared to batch-treating the well with liquid foam. This application maintains the well integrity and avoids well deliverability reduction. The injection system may also be used to continuously inject multi-blend chemicals downhole to treat various other issues such as scale, corrosion, and condensate banking as well as address downstream problems and reduce the need for surface inhibition. Designing the system with the appropriate chemicals and tubing material is the key to success. The selection of material and chemicals should take into account the CO2, H2S, high temperature, and pH concentration in the candidate wells.

The chemical injection string can be installed into a live well using a capillary unit, without the need to shut in or choke back production. This can be a rigless installation and will be similar to a coiled-tubing operation, but on a much smaller scale. The capillary unit is small and compact, and is mounted onto a truck/trailer. The unit can quickly and easily be mobilized and de-mobilized for operation, saving time and cost. Routine maintenance to the injection system is crucial for a long-term, successful application. The qualification of the chemicals should be stringent and needs to allow for friction loss through small inner diameters (IDs) that can withstand the pressures, temperatures, fluids and extreme downhole conditions. Using the continuous downhole injection system will positively impact well integrity, improve completion lifetime, assure production continuity, reduce downtime and treatment operating costs, and avoid coiled-tubing descaling operational costs.

Installing a downhole treatment system can also be used for other purposes if needed, such as H2S management, scale inhibition, controlling paraffin/asphaltene and treating downhole pumps.
Advanced Downhole Torsional Oscillation Control Tool Improved Dynamics and Field Average ROP
Authors: Al Rubaya Ahmed Meshaal , Alexeyenko Alexey , Khateeb Ashraf
Published: February 2024

The introduction of a novel torsional oscillation control technology, characterized by its high amplitude, extended attenuation length, and mode-coupled axial excitation, has been instrumental in enhancing drilling dynamics and augmenting the on-bottom drilling rate of penetration (ROP).

To effectively integrate this technology, a strategic approach was employed, which involved the use of a multi-point elastic contact force software for tool placement modeling. This software is adept at pinpointing string elastic breakover points and discerning localized contact side forces within the drill string under specific drilling conditions. To realize the desired outcomes, the deployment of two torsional oscillation control tools was deemed necessary.

A comprehensive evaluation was undertaken to gauge the efficacy of these tools. This involved juxtaposing the outcomes derived from the tools with the real-time operational results of downhole systems in the same field, spanning a 1000-foot interval. Key metrics, including downhole stick-slip and measurement while drilling (MWD) revolutions per minute (RPM), were meticulously assessed, considering their responsiveness to surface parameters and loads.

The findings were promising. There was a marked improvement in the field ROP average, witnessing an increase of 8%. Furthermore, there was a notable decline in the peak-to-peak RPMs (stick-slip) relayed in real-time through the MWD tool. Another significant observation was the substantial reduction in the effective downhole reactive torque when juxtaposed with the offset data. The drilling dynamics data underscored an optimal downhole RPM coupled with an enhanced weight transfer. This was in alignment with the energy efficiencies projected by the model, which factored in the influence of the torsional oscillation technology and provided insights into optimal tool placement. An ancillary discovery was the improved downhole directional control. A more overarching insight was the diminished energy consumption during drilling relative to the offset. Moreover, this pioneering technology played a pivotal role in lowering the downhole MWD temperature.

What sets this Torsional Oscillation Control technology apart is its innovative approach to mitigating the inherent elastic inertia moments within the drill string. These moments, which are typically stored and subsequently dissipated, are effectively addressed by this technology. A salient feature of this technology is its capability to curtail the energy loads, paving the way for heightened drilling efficiencies.
A Statistical Approach Analytics and Considerations for Extending ESPs Run Life
Authors: Albori Mostafa M. , Al-Khalaf Ahmed A. , Alsadah Hashim A. , Flippin Cleavant J.
Published: February 2024

Electrical submersible pump (ESP) system has been one of the major hydrocarbon artificial lifting mechanisms globally that is used to produce and sustain required rates. To avoid production interruption caused by ESPs undesirable events, a statistical approach had been conducted to look into ESPs up-time variation to find potential remarks to extend it.

Statistical analysis approach, such as probabilities distribution functions, had been conducted to analyze potential factors in electrical submersible pumps that exhibited extended running life. Multiple factors were evaluated and divided based on influences of run time, including: ESP downhole manufacturers, equipment conditions during installation, electrical motor sizes, soaking time, ESP settling environment, and ESP operation performance. This analysis helped to identify technologies, practices, and other factors that could have potential impact in ESP run life and the practicality in applying them to extend ESP run life.

Statistical approach of multiple factors and their effects were analyzed and evaluated to determine their impacts on ESPs’ up-time. Based on analyses, the findings were divided and characterized into their effectiveness range on the ESPs’ life time. The factors were divided into: little to no influence on the run life variations, some criteria had some influence on run life. While other criteria are suspected to have more effective role in determining and impacting ESP life. The studied factors and resultant recommendations are listed with implementation criteria to be considered to enhance future ESP installations and replacements to exceed the threshold ESPs’ target run life.

ESP running time is one of the major points to consider when it comes to fields dependent on ESP artificial lift method as the main production lifting mechanism. Therefore, extending ESP uptime can be of huge benefits in both operations and economics.
Enhanced Reservoir Understanding and Geomechanics With LWD High-Resolution Ultrasonic Imaging in an Unconventional Horizontal Well
Authors: Al-Naqeeb Mohamed Nizar , Ghneej Ali Faleh Abu , Al-Khabbaz Mohammed , Al-Ostath Mohammad , Ali Aisha Al-Bin , El Din Ali Hossam , Awadh Ahmad , Elshennawi Mohamed , Abdulkarim Anar
Published: February 2024

The Najmah carbonate-shale formation, an unconventional Jurassic kerogen layer in the North Kuwait region, has undergone testing, revealing its significant potential as a gas, condensate, and light oil reservoir in various well locations and as a prolific source rock. Given its exceptionally low porosity, the flow-control mechanism is heavily reliant on the presence of a natural fracture network.

This layer, previously referred to as Najmah shale, serves as the source reservoir, characterized by its abundant organic-rich clay with both argillaceous and calcareous components. This is evident in the notably high total gamma ray values, which are accompanied by elevated uranium levels on spectral gamma ray logs. Matrix porosity averages between 2% and 6%, permeability is low, ranging from 0.01 to 1.5 mD, and the total organic content (TOC) falls within the range of 2% to 30%. The precise identification and interpretation of fractures, bed boundaries, and borehole breakout through high-resolution imagery play a vital role in the optimization of completion design. In the context of horizontal wells, utilizing wireline technology has been challenging, making the preference for logging-while-drilling (LWD) acquisition evident.

The case in point pertains to a horizontal exploration well drilled in the Najmah formation of northern Kuwait, which employed a rotary steerable system combined with gamma ray and resistivity sensors. The drilling operation aimed to facilitate a multi-stage fracking completion. The comprehensive logging program also included measurements for density, neutron porosity, sonic, and high-resolution ultrasonic borehole imaging. To mitigate the risk of stuck events, the decision was made to utilize LWD acquisition. Traditionally, wells in the area were drilled in the minimum stress direction (SHmin) to intersect natural fractures perpendicularly for optimal fracking. Surprisingly, most of the natural fractures were found to be nearly parallel to SHmin. The data collected achieved a high level of quality, surpassing the expectations of the end data users. Within a measured-depth interval of 1,610 feet, a total of 96 natural fractures, 16 bed boundaries, and a few breakout intervals were interpreted.

The newfound insights into fracture orientation will be considered in future well design planning. These results have also proven invaluable in enhancing the prospects for future field development and completion design optimization. Further analysis and studies in the field are on the horizon to validate the interpreted findings.
Integrating Reservoir Mapping and High-Resolution Imaging Technologies Leads to Deliver the Fastest Well with Enhanced Production in an Unconventional Limestone
Authors: Al Ajmi Saad , Al-Azmi Mejbel , Al Otaibi Fahad , Joshi Girija , Pattnaik Chinmaya , Issa Dania , Danash Tarek , Tikhonova Izabella , Vican Kresimir , Abdulkarim Anar
Published: February 2024

Well placement in an Unconventional Jurassic Formations of North Kuwait is challenged by poor seismic resolution and high uncertainty in the stratigraphy leading to lateral variability of petrophysical parameters and thickness of the pay zone. The 6-9 feet thick target zone is located at 14,000 feet depth with expected uncertainty in the bed dipping angle. Key technologies were deployed to increase gas production in the tight carbonate formation with depositional uncertainties.

A pre-well model was built from existing offset wells to assess the well-placement capabilities. A combination of ultra-deep azimuthal resistivity mapping (UDAR) and gamma ray imaging tools were deployed for accurate landing and steering of the lateral section. The objectives were to keep the well trajectory in the payzone, anticipate and identify any abnormalities in the formation while passing through sub-seismic faults and enable rapid response to sudden changes in formation dip due to structural changes. The ultra-sonic high-resolution imaging (UHRI) tool was utilized across the lateral section to evaluate fractures, faults, and hole shape for optimizing completion design and enhancing production.

The 9.25″ landing phase successfully reached the desired target with around 1 degree higher-than-expected formation dipping angle. The target was identified and confirmed by the UDAR and additional logging-while-drilling (LWD) data. The 6″ lateral section was maintained within the target zone, achieving the maximum reservoir exposure passing through several geological features including faults, which were reflected on the resistivity inversions. The combination of deep and short-range measurements enabled successful well placement in the target zone. A spectral gamma ray image helped to identify the clay layers close to the wellbore, whereas the resistivity inversion identified multiple layers on a bigger scale, away from the wellbore. The UHRI helped to facilitate the optimization of completion design and further the field development by identifying 129 features including 125 fractures, 2 faults and 2 bed boundaries. The combination of UDAR with UHRI helped to deliver the fastest well in unconventional Najmah Limestone and supported optimization of the completion design providing enhanced production from the well.

This methodology was further recommended to be utilized in upcoming similar well profiles to improve the field development in Unconventional Najmah Limestone reservoir of North Kuwait
Advancements in Next Generation Collar Compact Integrated Logging While Drilling Technology
Authors: Elsherif A. , Verma J. , Alamin M.
Published: February 2024

This paper summarizes the steps and shows the results of field testing of a new Logging While Drilling (LWD) tool in a carbonate reservoir in the Middle East.

The next generation LWD tool was designed to achieve several tasks. The first task was to keep important sensors like Gamma ray and Density as close as possible to the tool bottom. This task is very important for Geosteering horizontal wells to allow fast reaction to environmental changes.

The second task was to combine all basic measurements (Resistivity / GR / Density / Neutron) in one collar less than 30 feet long. This was achieved with a 29 feet collar that has all the required measurements for basic petrophysical evaluation including fully compensated resistivity measurement with three depths of investigation.

The third task was to also include spectral Gamma ray measurement (Thorium / Potassium / Uranium) in the same collar. The Spectral GR sensor was tested in the tool with good results. The value of the Spectral GR across the formation was shown in this paper.

The final task was to include several azimuthal images capabilities with high resolution. That task was achieved with Gamma ray / Density / Caliper azimuthal images with 32 bins of resolution.

The tool was field tested first in Catoosa facility in USA and the data was compared with Wireline data from the same well. The comparison showed very good agreement in different measurements

The second phase of the field testing was done in Oman in a carbonate reservoir. Three trials were done with the tool in tandem with the main vendor tool and RSS while drilling. The data was recorded in memory mode using downhole batteries. After pulling out of the hole, the memory data was dumped and tested against vendor data with great success.

The imaging capability of next generation LWD tool has been verified as a great tool for Geosteering close to a shale barrier above the well trajectory in one of the three wells.