bluuebunny/crossref_metadata_2025 huggingface dataset:
Spiral Hole Moderation Enhances High-Resolution Borehole Image Interpretation Across Fractured Carbonate Reservoirs
Authors: Altarouti Alawi , Alotaibi Abdullah , Guerreiro Prudencio , Fakhrylgayanov Ayrat , Dolan James
Published: February 2024

Dynamic phenomena while drilling such as borehole spiraling or corkscrewing can create a physical imprint on the borehole surface, which mask fine features of imaging. During a drilling campaign in a carbonate reservoir using logging-while-drilling technology, corkscrewing was severely impacting the ultrahigh-resolution borehole image quality. As a result, fracture identification was affected that had significant implication on reservoir characterization, description, and hydrocarbon recovery strategies. Consequently, a collaborative project was initiated to find a solution to overcome these phenomena.

The impacted wells in the field and other nearby fields with similar formation characteristics were analyzed at first to find commonalities. Based on this investigation, a suggested solution to eradicate the spiraling was to reduce the interaction forces and minimize the adverse effect on the directional drilling capacity of the bottomhole assembly (BHA). A new bit design was required with design elements expected to mitigate or minimize borehole spiraling. With it, the bit gauge length was increased as well in successive wells combined with drilling parameter optimization. Drill bits from several vendors were used to study the impact of different bit designs.

The results from the detailed technical investigation indicated that borehole spiraling resulted from the bit-to-formation interaction. The testing of different bit gauge lengths and shapes was aimed at reducing the bit-to-formation interaction. On the other hand, the new bit design assessment raised another challenge, which was the BHA steerability and control. An increase in gauge length was expected to reduce the spiraling but potentially impact the steering capability negatively while drilling the well. Hence, a thorough design of the bit and BHA was performed to ensure the well steerability would comply with maintaining optimum well placement criteria. Each increase in gauge length minimized the severity of the borehole spiraling effect. The critical factors determined to reduce spiraling were the gauge design and length. Consequently, the borehole image quality obtained was significantly enhanced, enabling detailed fracture identification and reservoir characterization. Additionally, the enhancement in borehole image quality enabled openhole completion to be designed methodically to isolate conductive fractures with aim to extend well life, delay water breakthrough, and as a result maximizing reservoir sweep.

This paper presents the methodology and results of the bit design test to mitigate the presence of borehole spiraling. The quality of the ultrahigh-resolution borehole image was significantly improved, which enhanced the confidence in reservoir characterization, fracture modeling, and field development strategies such as completion design.
Impact of Surface Roughness on Rock Wettability
Authors: Aboushanab M. S. , Samad M. Abdul , Raza A. , Mahmoud M. , Al Kobaisi M. , Rahman M. M. , Arif M.
Published: February 2024

The wettability of the solid/fluid systems is an important property in several applications. The accurate determination of wettability in rock/fluid systems has a paramount role due to its fundamental influence on fluid distribution and the dynamics of multiphase flow in porous media. While various methodologies are available for the assessment of the wettability behavior of rocks, the goniometric approach, employed for contact angle measurements, is widely acknowledged for its direct applicability and appropriateness. This technique has the distinct advantage of facilitating wettability characterization for a broad spectrum of physicochemical conditions e.g., variations in pressure, temperature, and salinity.

Several investigations have reported contact angles under diverse conditions for various rock/fluid systems. However, contact angles often depict an inconsistency in terms of the observed wetting behavior of specific rock/fluid systems under identical conditions. One prominent contributing factor to these discrepancies is rock's surface roughness. Typically, smooth and polished rock surfaces are utilized for contact angle measurements, and this study depicts that ignoring the inherent surface roughness of rocks can have notable impact on its wettability.

This study analyzes the wetting characteristics of two distinct carbonate samples, each engineered to exhibit a spectrum of surface roughness values. Additionally, our investigation explores the impact of varying polish-abrasive sizes and types on both surface roughness and wettability, utilizing commercially accessible abrasives spanning a wide spectrum of dimensions, which include liquid silicon carbide (Si-C) and sandpaper. The results contribute to an enhanced comprehension of the mechanisms governing wettability fluctuations at the millimeter scale and thus explain the underlying mechanisms influencing wetting properties.
Development of Geomechanical Earth Model for New Wells with High Deviation Trajectory Plans in South of Iraq
Authors: Al-Asadi Yousif M. B. , Khan Danish A. , Abdi Hadi A.
Published: February 2024

The southern Iraq region has the privilege of having a group of the most important oil fields in the world. More than 3000 wells have been drilled in this region with different well designs, presenting major wellbore instability issues that includes caving, hole pack-off, stuck pipe and logging tools, hole enlargement, during drilling operation. Proper designing for any drilling campaign in these fields is the main step for achieving the targeted goals. Drilling the first boreholes with high deviation trajectory plan and new well completion design will require a consolidate geomechanical model as an essential tool for assessing drilling integrity, and guiding future well planning non-productive time.

The main objective of the current study is to construct high resolution 1D mechanical earth model (MEM) for new highly deviated trajectory plan developed recently in one of the fields using a wide array of input and calibration data. The generated 1D model was utilized to examine the Wellbore Stability using different failure criterion methods for evaluating drilling problems related to instability when penetrating through weak formations, then to determine the safe window of the mud weight for the wells with deviation above 75 degrees.

These analyses highlighted the change in drilling stability with well azimuth and inclination, which showed that drilling highly deviated borehole in the direction of minimum horizontal stress is different in the case of drilling with maximum horizontal stress direction The telling conclusion—from all the field observations collected so far and the 1D results obtained—is the need for raising mud weights and change the casing design in the highly deviated wells. The drilling campaign for future deviated wells in the studied filed improved by designing optimal mud weight and casing programs for any given wellbore trajectory.

Results and observations from this study, helps in designing the current and future drilling campaign by designing the optimal mud weight programs for any planned trajectory and drilling practices, and serves as a base for planning deviated wells aiming to reduce nonproductive times and increased drilling efficiency.
Sulfate-Based Scales: Why Sulfate Ion Concentrations Matter
Authors: Almulhim N. , Alotaibi F. , Rafie M. , Alrufail T.
Published: February 2024

Waterflooding is frequently applied in oil and gas reservoirs to sustain the reservoir downhole pressure and achieve a high rate of hydrocarbons production. The main challenge of water flooding is the potential to induce mineral scale depositions, especially when the injected water contains a high sulfate content. The objective of this paper is to determine the minimum threshold of sulfate contents present in the injected water that will not lead to mineral depositions through theoretical and experimental work.

This study will showcase scale simulation and laboratory experiments involving multi-compositional water interactions with various sulfate concentrations ranging from 100 to 5,000 ppm. The study scheme starts by water preparation for the proposed brines, followed by geochemical analysis using Inductive-Coupled Plasma (ICP) to confirm the physical and chemical properties. Afterwards, scale risk assessment was performed using ScaleSoftPitzer™ to evaluate the scaling tendency. Finally, static bottle tests are conducted for a 48- hour testing period at temperatures ranging up to 260°F using HPHT aging cells at different mixing ratios.

The scaling tendency assessment indicated a calcium sulfate and strontium sulfate precipitation when sulfate content exceeded 300 ppm. Although 5,000 ppm of sulfate content showed theoretically a low scaling index of gypsum and celestine, the scale mass was estimated to be nearly 2,500 and 500 mg/L, respectively at equivalent mixing ratio. Also, it was observed that as the sulfate content increases, the scale severity increases as well. The experimental compatibility tests reinforced the simulation findings, which showed similar result of inorganic sulfate-based scale precipitation that was observed after 48 hrs. testing time.

The paper shares a system approach for water compatibility assessment and provides different scenarios using both simulations and water-water lab tests to confirm these predictions. It will also highlight how to mitigate the potential risk of scale and formation damage during water flooding.
Emulsified Epoxy Resin for Mitigating Sand Production
Authors: Chang F. F. , Liang F. , Lee Christie , Berger Paul
Published: February 2024

Sand production from unconsolidated or crushed weakly consolidated formations due to high reservoir fluid flow velocity leads to operational problems and limits their potential. Many techniques are practiced by the completion and production engineers to combat such challenge. This paper discusses the development and testing of a novel polymeric resin formulation that consolidates sand grains to form a high regained permeability and high compressive strength rock matrix, allowing high production rate without sanding concern.

The new chemical solution utilizes a low viscosity water external epoxy emulsion to strengthens the bonding of sand grains while maintains flow capacity. The chemical formulation contains two components that can be batch mixed at wellsite, injected by coiled tubing or drill pipe, and shut-in in the formation to cure for 24 to 48 hours depending on the reservoir temperature from 200°F to 320°F. Unlike most of the currently used resin consolidation products, by which post flush is required to maintain opening of the pore space, the emulsion separates during the curing process with epoxy attaching to the sand surface while the water phase occupies the pore to help keep the flow path open.

Laboratory experiments in both water or oil saturated sand packs showed the treated loose sand are well consolidated with the unconfined compressive strength significantly greater than 1000 psi and the regained permeability up to 54%. No sand production was observed in the produced fluid at high flow rates. This paper focuses on the laboratory testing of the water external emulsified epoxy. The chemical mechanism and evaluation methodology are described.

Having the water emulsified epoxy resin system allows the convention water based diverting techniques such as foam to be used during treatment of long sections. Another benefit of the water based emulsified epoxy is its operation simplicity and safety. The flash point concerns for safe field operation is completely alleviated with this chemical formulation.
Using an Advanced Geomechanics-Based Workflow to Prevent Wellbore Shear Failure When Drilling Across Depleted Formations
Authors: Omer Mohammed , Duarte Miguel , Fragachan Francisco E. , Alvarez Alfredo
Published: February 2024

Drilling laterally and in the direction of minimum stress assists in optimizing hydraulic fracture stimulation designs. However, it poses a huge risk of hole instability due to stress concentration while drilling across the minimum stress direction. Generally, when breakouts are encountered, the strategy is to increase the mud weight, but in scenarios where the mud weight window is very narrow, trying to avoid fracture initiation will potentially lead to shear failure or breakouts. This makes drilling highly challenging. One would need to have a deep understanding of the weak formations and plan a wellbore strengthening strategy to mitigate instability issues when drilling across these formations.

This research used a semi-analytical model based on the Gauss-Chebyshev polynomial to quantify wellbore strengthening. The model provided a comprehensive analysis of the formation strengthening in different scenarios and predicted fracture width distribution, coupled with the fracture initiation pressure. Combined with the mud loss volume, this algorithm helped quantify the loss and provided a strategy for corrective action. We used the learnings from the model to design a wellbore strengthening material to prevent shear failure of the weak formations or the formation with high porosity. This effectively prevented the wellbore from collapsing.

In this paper, we present the results from formations in the Middle East and Asia where this approach was used to predict the instability in the formation at the planned mud weight. The effect of the mud weight was quantified to predict the breakout so that the appropriate strategy was utilized for wellbore strengthening.

This integrated approach provides a workflow for drilling through depleted zones, weak formations, and challenging wells by considering stress behavior. Additionally, the case studies presented in this paper provide key information on mitigation strategies for unstable or weak formations.
Digital Emission Footprint Estimation as a Design Criteria to Fulfil Sustainable Development Goals
Authors: Majumdar C. , Naik C. K. , Garg A. , Suryadi H. , Dara A. K. , Hussain S. A. , Singh A.
Published: February 2024

This paper highlights a pioneering approach to address carbon emissions in the oil and gas sector. It emphasizes the growing focus on environmental sustainability and how that can be achieved using different tools at different stages of the oil and gas (O&G) exploration. The study introduces a digital well planning solution that estimates carbon footprints for the entire well, enabling real-time emission assessment and optimization during design. The analysis of two planned wells identifies significant emissions from drilling, cementing, and casing activities. This data allows for cost-effective, well design adjustments, contributing to emission reduction objectives. The presentation of data in measurable charts aids compliance with regulations and enhances industry-standard emissions measurement. The integrated platform breaks down silos and enables proactive environmental sustainability efforts.
Optimizing Managed Pressure-Drawdown Flowback for Shale Gas Well with Complex Fracture Network with Fracture Closure and Two-Phase Flowing
Authors: Wang Junlei , Wei Yunsheng
Published: February 2024

Shale gas reservoir is fractured formation with hydraulically fracture network surrounding the shale matrix. Two-phase (water/gas) flowback schedule of fractured well is designed without a sufficient understanding that how the BHP-drawdown the well productivity. A two-phase coupled model is established to simulate the transient gas- and water-production from complex fracture networks. In this work, a new model was established to account for unique transport mechanisms. Different properties of flow mechanisms are assigned to fracture-network domain, stimulated-reservoir-volume (SRV) domain, and non-SRV domain. SRV is characterized by primary- and secondary-fracture network with different propped conductivities along horizontal wellbore. Non-SRV is described by several sets of isolated discrete fractures associated with dual-porosity system. The model is solved by numerical approach for performance forecasting. Embedded discrete fracture modeling (EDFM) and black-oil simulator are used to improve the computational efficiency. By using the numerical model, an efficient framework is established to obtain the optimum flowback scenario based on EUR maximization by using high-dimensional parameter design of experiment. The results show that the effective conductivity deteriorates with the decreases of pressure and water saturation in fracture network during two-phase flowback. The optimum flowback strategy enhances the peak of gas production rate and diminishes the dewatering time simultaneously. Meanwhile, the stress sensitivity contributes to the decreasing of network conductivity, and a more conservative drawdown is suggested for the fracture network with more stress-sensitive conductivity.
Closed-Loop System in Land Drilling Rig
Authors: Alharbi Magbel , Motawee Ibrahim , Albinali Mohammed
Published: February 2024

Closed-loop system in land drilling rig are analyzed in this paper, which considers a first practice "no waste pit". The focus is on the skip-and-ship method for drilling cuttings disposal and excess drilling fluid management. By examining the design, implementation, and best practices of the recycling system, the study aims to enhance waste management, reduce environmental impact, and optimize drilling operations for improved safety and cost-effectiveness.

The study will experimentally investigate the impact of closed-loop system in land drilling rig as an alternative to conventional drilling methods that cause environmental issues. This study evaluates a closed-loop system's effectiveness in managing drilling waste, its environmental impact, safety and cost. The goal is to promote sustainable drilling and reduce environmental harm.

The experimental investigation of closed-loop system in drilling rig demonstrated significant waste management improvements, achieving 100% restoration of a 9,285 ft well with six sections. A dry location with no waste pit, 263 skips transported 1,709 tons and 5,786 BBLs of waste drilling fluid, including harmful oil-based mud. Drilling fluid consumption reduced by 6%, and the system led to zero spills, highlighting its potential to minimize environmental impacts.

The closed-loop system effectively managed drilling waste. Integrating skip-and-ship methods for drilling cuttings disposal and waste fluid management provided robust and efficient waste reduction and restoration. By eliminating spills, the system mitigated environmental risks, improved safety and cost-effectiveness, saving cost from skip-and-ship costs needed for two waste pits. Recycling 63% of waste mud was achievable with the closed-loop system.

Closed-loop system in drilling rig offer immense potential for waste restoration, reducing environmental impacts, and maintaining zero spills. Implementing closed-loop system and optimizing waste management practices can lead the drilling industry towards sustainable and environmentally responsible operations. The study emphasizes the importance of ongoing research and development in closed-loop technology, paving the way for further advancements in drilling waste management, environmental preservation, and operational efficiency.

This paper presents novel insights into closed-loop system in drilling rig, emphasizing their potential to eliminate waste pits and spills through skip-and-ship methods for cuttings disposal and recycling opportunities. Highlighting environmental, safety, and cost benefits, the study explores challenges and future trends, advancing the industry's comprehension of sustainable drilling practices. The paper promotes the broader adoption of closed-loop system as standard rig equipment.
Calcium Sulfate Scale Inhibitor: Does the Carbon Backbone Length Matter?
Authors: Albaiz A. , Almubarak T. , Alissa F. , Owais A. , Aljeaban N.
Published: February 2024

Calcium sulfate (CaSO4) scale precipitation is a challenge faced in the oil and gas industry where it can cause a variety of issues that lead to productivity decline. Amino-phosphonate-base scale inhibitors are used to prevent this type of inorganic scale and have shown great success in the industry.

A common misconception is to believe that high molecular weight amino-phosphonates perform better than their low molecular weight counterparts. This study systematically compares performance of scale inhibitors which have the same number of functional groups but different molecular size and backbone chain length. The study shows the influence of changing the molecular size and backbone chain length on the inhibition efficiency.

Two amino-phosphonate-based scale inhibitors are tested in this work: Ethylenediamine tetramethylenephosphonic acid (EDTMP) and Hexamethylenediaminetetramethylene phosphonic acid (HDTMP). These inhibitors have the same number of functional groups, but they differ in the length of the carbon backbone chain. The inhibition efficiency of each inhibitor is measured through its ability to prevent formation of CaSO4 in a brine containing up to 6,000 ppm calcium ions (Ca2+) and an equivalent amount of sulphate ions (SO42-). Moreover, the remaining concentration of Ca2+ in the solution is measured using Inductive Coupled Plasma (ICP). The results of the study shows that the inhibitor molecules with shorter chain length, EDTMP, have higher inhibition efficiency than the ones with longer chain length, HDTMP. That is because a small dose of EDTMP can efficiently inhibit CaSO4 precipitation while a big dose of HDTMP to do the same job efficiently. Environmental scanning electron microscope (ESEM) is employed to study the effect of the inhibitors on the morphology of the formed scale. The morphology of the formed scale after using the low doses of the inhibitors are investigated by Environmental Scanning Electron Microscope (ESEM), and the resulted images show that the CaSO4 precipitates exhibit deformed shapes compared to the CaSO4 precipitates where no inhibitor is used.
Characterization of Induced Fractures in Carbonate Formation Using Multi-Frequency Dielectric Technique
Authors: Alsamadony Khalid , Al-Ofi Salah , Abdallah Wael
Published: February 2024

The multi-frequency dielectric tool is commonly used to estimate water-filled porosity, water salinity, and rock texture. These are estimated from interpretation (petrophysical) models that analyze the dielectric and conductivity dispersions. Previous studies used dielectric permittivity simulators to characterize rock fractures from digital rock models. However, there is no experimental work has been done to characterize fractures from multi-frequency dielectric measurement and validate the simulation results.

In this study, dielectric measurements (coaxial probe) were utilized to characterize the geometry of the induced fractures in calcite samples. The dielectric measurements of the samples were acquired before and after inducing the fractures. These fractures were drilled with different diameters and lengths. Also, fractures geometries and locations with respect to a measurement reference are investigated. Afterwards, the dielectric dispersion data were analyzed and correlated with fractures geometry to derive a mathematical model for fractures geometry (aspect ratio) prediction.

In the results, after controlling potential factors that affect dielectric dispersion, it is observed that the location of the induced fracture affects the dielectric dispersion. This may hinder the dielectric sensitivity to fractures with different diameters. Although dielectric measurements are more sensitive to the change in fracture length, they could be limited by the depth of the investigation. Based on these observations, several correlations are presented for the fracture aspect ratio of the studied samples. These correlations use the slope and average values of the dielectric and conductivity dispersions at a specific frequency range.

This work experimentally demonstrates the sensitivity of the dielectric and conductivity dispersions to fracture geometry. Digital rock models of the studied samples could be developed. Thus, the results of this work may be utilized to calibrate and validate dielectric permittivity simulators to match the actual measurements. Consequently, the need for laboratory measurements could be reduced.
A Simple Yet Impactful Innovation to Optimize Production of Low-Quality Reservoir (LQR) by Using a Modified Venturi Choke, Pilot Case at Matured Waterflood Field Bravo, Central Sumatera Basin
Authors: Fadli Ade , Rahman Aulia , Putranto Daniel Hadi , Dewi Cintani Kusuma , Nurjaman Muhammad Saeful , Ramadhan Iftikar Luthfi , Afton M.
Published: February 2024

In a mature asset like Bravo field in Central Sumatera Basin, the ‘easy to produce’ oil is becoming increasingly rare and hard to find. Therefore, pursuing oil at the low-quality reservoir (LQR) has become one of the main focuses nowadays. Despite having huge potential due to its low recovery nature, optimizing LQR production comes with set of challenges. This paper highlights a successful innovation to unlock the LQR potential, offering a solution to maximize production.

The innovation involves the application of a modified venturi choke (VC). Basic principle of this method is producing the LQR zone (low rate, low watercut) with the assist from a better-reservoir quality zone below, namely High-Quality Reservoir (HQR) zone (high rate, high watercut). Unlike the conventional commingle approaches, the modified VC is strategically placed between the zones, applying fluid restriction to the HQR zone. Acting as a downhole choke, it induces a substantial pressure drop, resulting in a jetting effect that efficiently strips out fluids from the LQR zone, thereby enabling optimal oil production contribution.

Pilot execution on the first 2 wells in Bravo Field successfully delivered 100 BOPD incremental oil gain, proven that this newly developed method is working very well. The installation of the venturi choke (VC) has led to a substantial improvement in oil contribution from the LQR zone, a fact confirmed through oil finger printing analysis. Notably, the LQR zone, which was theoretically unable to produce even with the smallest pump and would not contribute significantly through conventional commingle methods, has demonstrated its production potential using this approach. The established flow process and screening criteria are also proven effective to capture potential candidates that cannot be produced with traditional commingle methods. Comprehensive analysis of historical production data, swab tests, G&G interpretation, reservoir simulation, and well modeling played a pivotal role in selecting the most suitable LQR candidate for this optimization. Additionally, considering VC material is available at relatively large quantities on hand, makes it feasible to implement the same approach in numerous other LQR potentials within the field and the surrounding region. This scalability further highlights the benefit of this method in unlocking LQR potential beyond the initial pilot wells.
Innovative Water Conformance Solution Led to Enhanced Well Performance
Authors: Murtaza Shoaib , Madan Mohammed H
Published: February 2024

Over the years, the oil and gas industry has mastered and perfected a range of techniques to shut-off undesirable water production or to minimize it. Mechanical and chemical water-shut-off techniques produced the desired results and are still in use. Chemical water-shutoff has evolved over time with many novel chemicals/products entering market.

Advanced water conformance solutions have recently come into existence in the form of sophisticated downhole completions like inflow control devices (ICDs) – both passive and active, water adaptive/responsive ICD screens, surface controlled smart completions, and so on. All these completions have their own limitations and challenges.

The paper explains a novel water conformance process for wells equipped with shiftable ICDs with open hole packers for compartmentalizing the reservoir section based on open hole log interpretation and formation characteristics. To maximize the chance of job success, careful evaluation of completion and production is a must before deploying a coiled tubing (CT) conveyed shifting tool to shift open/close various ICDs. To accurately perform and record ICD shifting events, a stroker is deployed as part of the bottom hole assembly (BHA). Before deciding on the final ICDs to be shifted, a suite of production logging tools (PLTs) and noise logging are run. Based on the outcome of the logging job, the final dispositions of ICDs are decided. Stroker's current signature confirms the ICD shifting process at surface. Noise logging is used to confirm the integrity of open hole packers. The method resulted in sustaining well performance and concomitant decrease in water production.

This paper describes detailed job planning, field data interpretation process, decision making and some key insights for enhancing the whole work process.
Method to Identify Perforation Locations for Fracturing Deep and Tight Gas Reservoirs
Authors: Xia K. , Wang W. , Cui Y.
Published: February 2024

Fracture initiation has been a challenging issue for fracturing deep and tight gas reservoirs, which generally requires a high breakdown pressure for hydraulic fracturing treatment. In this situation, fluid injection has to terminate at the very beginning. Toward predicting and solving this issue, a novel fracturing system for deep and tight sandstone gas reservoirs was developed. Other issues related to perforation cluster layout design will be discussed as well. The key components of the fracturing system and some criterion will be introduced in this paper, which can be used to identify the ideal perforation locations along the landing part and select the right perforation strategy accordingly. The main components of the fracturing system include: (1) Evaluating the log-based diagenetic rock typing and flow index; (2) 1D mechanical earth model; (3) calculating the breakdown pressure envelope along the well trajectory of the landing part; (4) calculating the optimal perforation directions along the landing part; (5) select the first set of perforation locations based on the log-based diagenetic rock typing and flow index; (5) narrow the first set of perforation locations to a second set of perforation locations based on the breakdown pressure envelope; and (6) compare the breakdown pressure envelope of the second set of perforation locations to a maximum downhole pressure the used wellhead can safely provide to determine a perforation strategy. The computational framework to calculate the breakdown pressure envelope and optimal perforation directions is applicable to arbitrary well trajectory. The fracturing system has been used to provide pre-fracking support for wells that landed in deep and tight sandstone reservoirs, which can assist in selecting locations with good rock typing and relatively low breakdown pressure. Also, it can indicate whether oriented perforation should be used. By taking these efforts and procedures, the fracturing success rate for deep and tight gas reservoirs can be improved, which has been verified in practice. Example studies from the field will be provided to demonstrate the fracturing system's performance and applicability.
Real Time Petrophysics via Artificial Intelligence in Brown Field Development
Authors: Shah Jamari Mohd , Sansudin Salmi , Fadhil M Imran M , Gazali Ismail Marzuki , Zakeria Ahmad Fakrudin , Husni Husiyandi
Published: February 2024

The paper introduces a novel approach to evaluate well log data in real time during downhole data acquisition. This approach has been successfully implemented in multiple drilling projects. It relies on effective real-time data transmission with the key enabler of the system is development of the well log artificial intelligence module. Time is of the essence during drilling operations. Hence, any efforts towards increasing the operation efficiency can lead to a safer and more optimized well delivery. A machine learning application for real-time petrophysical evaluation during drilling was successfully developed to achieve this ambition. The application which named Well Log Data Artificial Intelligence was tested in a Malaysia complex brownfield infill drilling project, where it proved to promote a seamless decision-making process during drilling and simultaneously lead to financial and operation value creation. The application uses selected key wells in the field as training dataset before the actual drilling operation. Random Forest ensemble was utilized for model learning and correspondent petrophysical evaluation, The module can predict reservoir characteristics in real-time by leveraging on feeder open hole raw curves as inputs with integration of existing trained model and real time data transmission. Moreover, the application provides easily accessible prediction results through the same display interface as the real-time data transmission. This makes it attractive for multi-disciplinary utilization during discussion.
Fracturing Simulation and Design Optimization of Fracture Network in Non-Uniform Stress Field of Deep Shale Gas
Authors: Lin Chen , Zhao Jinzhou , Ren Lan , Lin Ran , Wu Jianfa , Wu Jianjun , Song Yi , Xie Mengke , Hu Zheyu
Published: February 2024

The deep shale is influenced by multiple tectonic movements, resulting in well-developed reservoir faults and a non-uniform distribution of the stress field near the wellbore. The volume of the fracture network may be impacted by non-planar, asymmetric, and irregular behavior during hydraulic fracturing. One important aspect influencing gas well productivity is the volume of the fracture network. In the complex structure of deep shale gas reservoirs, a model is established in this study to define the non-uniform stress field near faults and to predict the propagation of fracture network. By contrasting the models with microseismic monitoring data from the mining field, the models' dependability is confirmed. The impact of fault type, fault offset, length, height, strike, dip, and distance on the fracture network volume is quantitatively investigated, and the influence of fault characteristic parameters on the stress field is quantitatively calculated. The ideal stimulated reservoir volume (SRV) is the design objective for hydraulic fracturing inter-cluster spacing, which is optimized based on the fault characteristics of the Y101 well area in southern Sichuan. The findings indicate that the stress field rotates clockwise near reverse faults and right-lateral strike-slip faults, and counterclockwise near normal faults and left-lateral strike-slip faults. A bigger fracture network volume results from the small stress difference near normal faults and right-lateral strike-slip faults, whereas a smaller fracture network volume results from the significant stress difference near reverse faults and left-lateral strike-slip faults. The following is a ranking of the fault structural parameters that have an impact on the volume of the fracture network: dip > strike > displacement > distance > height > length. In the case of I fault, the ideal distance between clusters is smaller the closer to the fault the larger the horizontal stress difference, which prevents the fracture network from propagating. When the strike angle for Grade II, III, and IV faults is less than 50°, the closer the fault is to the fault, the larger the horizontal stress differential. This does not promote the fracture network's growth, and it also results in a smaller ideal spacing between clusters. When the strike is more than 50°, the ideal distance between clusters of perforations is bigger and the horizontal stress difference is less the closer the strike is to the fault, which promotes the propagation of the fracture network. Horizontal wells have to be positioned appropriately away from faults; a distance of more than 2000–4000 meters is recommended for level I faults, more than 1500–2500 meters for level II faults, more than 700–1200 meters for level III faults, and a closer distance is permissible for level IV faults.
Driving Efficiency Forward: Harnessing Digitalisation for Rig Energy Management
Authors: Saghir F. M. , Daif M. Y. , Alarfaj M. A.
Published: February 2024

The oil and gas industry has long been at the forefront of innovation and technology in its quest to optimise operations, reduce costs, and minimise environmental impacts. One of the paramount challenges in this industry is enhancing rig energy efficiency. The traditional approach to rig energy management involves manual monitoring and control systems, which are often cumbersome and less effective. However, the advent of digitalisation offers a transformative solution to this challenge. By leveraging digital technologies, including the Internet of Things (IoT), Edge Analytics, and Machine Learning, the industry can effectively track and manage rig energy consumption, equipment performance, and emissions.

This paper provides a comprehensive review of the use of digitalisation for rig energy efficiency tracking, exploring various technologies, methodologies, their impacts, and the potential for future advancements. It also addresses challenges, future perspectives, and the potential for sustainable and efficient energy operations in the oil and gas industry.
Advancing Relative Permeability and Capillary Pressure Estimation in Porous Media through Physics-Informed Machine Learning and Reinforcement Learning Techniques
Authors: Kalule R. , Abderrahmane H. A. , Ahmed S. , Hassan A. M. , Alameri W.
Published: February 2024

Recent advances in machine learning have opened new possibilities for accurately solving and understanding complex physical phenomena by combining governing equations with data-driven models. Considering these advancements, this study aims to leverage the potential of a physics-informed machine learning, complemented by reinforcement learning, to estimate relative permeability and capillary pressure functions from unsteady-state core-flooding (waterflooding) data. The study covers the solution of an inverse problem using reinforcement learning, aiming to estimate LET model parameters governing the evolution of relative permeability to achieve the best fit with experimental data through a forward problem solution. In the forward problem, the estimated parameters are utilized to determine the water saturation and the trend of capillary pressure. The estimated curves portray the relationship between relative permeability values and saturation, demonstrating their asymptotic progression towards residual and maximum saturation points. Additionally, the estimated capillary pressure trend aligns with the existing literature, validating the accuracy of our approach. The study shows that the proposed approach offers a promising method for estimating petrophysical properties and provides valuable insights into fluid flow behaviour within a porous media.
Energy Efficiency Application for Reservoir Pressure Management by Optimum Water Injection Strategy and Sustainable Low Carbon Surface Water Disposal
Authors: Susatyo Y. , Aghbari H. , Asmi H. , Lawati M. , Abri M. , Saadi F. , Hinai G. , Wardi A.
Published: February 2024

Rima cluster fields are mature brown fields located in the south of the Sultanate of Oman (figure 1). They are on production for more than 40 years since 1980s and all production process at on central main production station called Rima production station.

Over many years of productions, All Rima station fields have developed high water cuts, average of 96% Water Cut (Figure 2). The Rima production station processes the incoming gross fluids, separating oil and water, dehydrating the crude for export, and partially treat water for bulk removal of oil in water.

The excessive produced water from Rima production station is disposed into Deep Water Disposal (DWD) wells. This disposal process requires a pumping station to boost the water pressure from atmospheric pressure to over 150 barg to be disposed deep in the disposal wells.
Solution for Improving the identification of Low Relief Carbonate Reefs in Shallow Water Areas
Authors: Zhang Hongjun , Du Houyu , Wang Jun , Cheng Hu , Shen Yang
Published: February 2024

Pre-stack depth migration using high precision velocity model is an effective tool to restore the real structures under the variation of lateral interval velocity. Due to lots of seismic data in shallow water area with low coverage and large minimum offset, it is difficult to use shallow seismic data to invert the correct velocity, which will cause large velocity error to the targets when calculating deep velocity. Meanwhile, the frequency bandwidth of carbonate reefs is narrow owing to the absorption of muddy seabed and formation. How to improve the imaging accuracy and resolution of the carbonate reefs by the limited seismic data becomes the key to the reservoir research and subsequent drilling.

Two of the key challenges for velocity model building in the shallow water area with the interest targets of low relief carbonate reefs are a heterogeneous overburden, such as small scale low velocity channels and the presence of high velocity carbonates, which result in strong velocity contrasts. Two model building techniques have been presented in this paper to address these challenges. FWI has been shown to be highly effective in resolving overburden heterogeneity and high-precision tomography allows us to preserve sharp contrasts in our velocity models, TTI QPSDM solved the imaging accuracy of low relief carbonate reefs and broaden the frequency band.

Full waveform inversion has certain requirements on the accuracy of initial velocity model. The greater the velocity model error, the more serious the FWI local minimum caused by cycle skipping. On the other hand, the interval velocity model converted from RMS velocity with Dix formula lacks velocity details in shallow layers due to the small acquisition coverages causing hard to get accurate velocity from seismic data, and shallow logging data are not usually recorded by reason of limited investment and less target interest. How to get relative accurate initial velocity model, high quality shot gathers with rich low frequency and signal to noise ration improvement is important points in this paper.
Dynamic Resolution TLFWI to Resolve the Structure Distortion Beyond the Penetration of Diving Waves in Tuna PSC Block
Authors: Wang Jun , Chen Yitao , Deng Peipei , Yu Ziqin , Crabtree Nick , Mulyono Dono , Juliansyah M. Nauvall
Published: February 2024

Faults and carbonates are well developed throughout the Tuna PSC block, offshore Indonesia, forming good traps for hydrocarbon reservoirs. However, the deep target depth with strong shallow overburden effects makes it challenging to resolve the real structure with traditional methods, especially when the available datasets are acquired with narrow azimuth and limited offsets. This paper demonstrates the application of Dynamic resolution Time-lag Full waveform inversion (DR-TLFWI), which uses both diving waves and reflections for velocity update with optimized low- and high-wavenumber components, to address the challenges in the deep part of the image that lies beyond the reach of diving waves. DR-TLFWI with dynamic weighting applied to different gradient components enables more effective utilization of the full wavefield. This approach succeeds in resolving the complex velocity field and improves the imaging of deep targets on the study data with a limited offset range. With DR-TLFWI applied, the imaging uplift results in less structural undulations and better mapping of the upthrown fault-bound closure, potentially reducing uncertainties in the subsequent exploration.
AI Based Unstructured Document Geotagging Solution
Authors: Pal Anik , Mishra Nirbhay , Gandhi Mihir
Published: February 2024

In the oil and gas industry, extracting relevant information for new projects often involves scrolling through a large unorganized or semi-organized unstructured electronic repository of unstructured documents inside an enterprise. However, the digital availability of these unstructured documents and their proper characterization with respect to E&P domain objects remain a significant challenge. To address this issue, we developed an - "AI-based unstructured document geotagging solution" that utilizes text mining, optical character recognition (OCR), natural language processing (NLP), and named entity recognition (NER) to extract entity relations for spatial E&P objects and document category (for example well completion, log data print, daily drilling report etc.) from documents content autonomously. We employed popular language models spaCy, Roberta-base, GPT2 and GPT3.5 and compared the results. The extracted information was then linked to a structured database that contained geo-locations. The solution was developed using the company specific data sciences platform but is capable of being deployed for an operator on-premises or in the cloud. The end-to-end solution can be integrated with any GIS-based dashboard solution, allowing user to select objects from the map and the model can predict related documents to the objects along with document category. This solution will allow user to obtain an organized list of related documents out of electronic repository with unorganized collection of uncharacterized documents, which will allow the user to prioritize and deploy only content of interest to be ingested to the insight and analytics system often hosted in cloud environment.