bluuebunny/crossref_metadata_2025 huggingface dataset:
Fractal Dimension Measurement Using Wireline-Derived Saturation Height Function
Authors: Altayeb Mohammad , Glover Paul W. J. , Lorinczi Piroska , Cuddy Steve
Published: February 2024

Fractal geometry represents a self-similar object or behavior over different scales. Fractals occur in many aspects of nature including reservoir pore geometry. Fractal dimension is a key parameter that represents how complexity changes with scale. This study attempts to measure the fractal dimension using a power law-based saturation height function that is derived from wireline data. The approach involves estimating the saturation height function (SwH) using Cuddy's method with wire-line data. This method plots water bulk volume (BVW) against height above the free water level (H). Major steps to estimate SwH include identification of the free water level, the presence of shale volume and calculating porosity, water resistivity and water saturation. Cuddy's method often reveals that SwH follows a power law behavior, which is expressed linearly when logarithmic scales are used. Consequently, SwH can be estimated by fitting a line to the data and obtaining two parameters a and b representing the intercept and gradient, respectively. The SwH of 13 wells were derived using Cuddy's method and showed acceptable fit to the power-law assumption. The parameter b, which represents the gradient of the best fit line, has been hypothesized to be related to the fractal dimension. Therefore, the estimated SwH may provide a measurement of fractal dimension of the pore geometry. The fractal dimension is related to the pore geometry heterogeneity, where higher fractal dimension implies higher heterogeneity. Fractal dimension applications include heterogeneity evaluation of pore geometry, reservoir modelling and performance simulation.
Prediction and Optimization of Rate of Penetration By Simulation, Case Study from Kuwait Fields
Authors: Alajmi Ali , Aladwani Faisal
Published: February 2024

Drilling expenses are a persistent concern for the majority of oil exploration and production companies. Despite declining oil prices, drilling costs continue to rise over time due to inflation and industry demands for more complex unconventional and deeper wells to meet production needs. From the inception of the oil industry, penetration rate has been considered a crucial element in cutting down drilling expenses. Oil companies endeavor to enhance rate of penetration through various strategies, including the implementation of new drilling technologies, optimization of drilling fluids, underbalanced drilling and managed pressure drilling, as well as trajectory and parameter optimization. However, due to the complexity in predicting rate of penetration directly, evaluating these methods successfully without field trials within similar geological formations poses a significant challenge. This introduces additional cost risks without guaranteeing success. Therefore, conducting field trials becomes essential for selecting an optimal scenario and driller will perform various drill-off tests by varying multiple sets of parameters. The process itself is resource-intensive and time-consuming, and the driller needs to have prior experience within the same field. Therefore, a more practical approach to predicting and optimizing rate of penetration while minimizing additional costs and risks without guaranteed success is necessary. This research evaluates a modern rate of penetration simulator for prediction and optimization using a case study of a horizontal well in Kuwait. The development plan for the targeted reservoir is to drill similar horizontal parallel wells, hence there is a valuable opportunity for rate of penetration optimization, due to the homogenous lithology and properties from nearby wells. A successful model was obtained that provided very close results to the real case results with only 0.1% cumulative rate of penetration absolute percentage error, 17.9% rate of penetration mean absolute percentage error, 15.4% weighted mean absolute percentage error, 0.93 drilling time coefficient of correlation and 0.87 drilling time coefficient of determination. Various methods were evaluated to determine the optimum rate of penetration. Final results indicate an opportunity to increase rate of penetration by 33% and prove that there is a chance of achieving an optimum rate of penetration that tends to reduce drilling costs by 18%.
Revolutionizing Drilling Efficiency in Hard and Abrasive Formations Through Innovative Cutter Development and Design Optimization
Authors: Suleiman A. , Bailey M. J. , Qahtani Ali Mutlaq , Alhassan Yousef Mohammed , Hashim Ahmed Omar , Centala P. , Roberts S.
Published: February 2024

Hard and abrasive formations are commonly found in challenging Middle East reservoir sections. These sections are often drilled with up to 10 bits, driving up drilling costs. Low rate of penetration (ROP) and accelerated cutter wear are the primary failure mechanisms encountered. Conventional drill bits have proven unsuitable and uneconomical. This paper presents the development of a Polycrystalline Diamond Compact (PDC) cutter grade housed in a rotating mechanism that has resulted in ground-breaking drilling efficiencies in these formations.

A comprehensive study investigated the cutter-rock interaction and identified the underlying causes behind the accelerated cutter wear in these hard abrasive formations. Following this, laboratory tests were conducted to replicate the failure modes encountered in the field. Five new PDC cutter grades were developed and tested against the field results. In parallel, critical drill bit design levers such as cutter size, blade count, backrake, and cutter chamfer were field tested to determine the most effective configuration. Finally, the optimal cutter grade and bit design levers were integrated into a rotating cutter mechanism and field tested.

The results of this paper focus on validating the development process of the cutter grades, design levers, and the rotating mechanism, both individually and when all three are integrated into an optimal product. Among the three cutter grades laboratory tested, cutter grade C scored the highest, demonstrating a 35% increase in abrasive strength compared to the baseline cutter grade. Field test results against the baseline design with cutter grade C demonstrated a 156% increase in interval drilled.

The optimal design levers combine a 16-mm cutter size with high backrake. The high backrake maximizes the PDC cutter diamond volume in contact with the formation, while the larger cutter size increases the point loading on the formation, minimizing drilling efficiency loss. A 5.875-in. bit that incorporated the design levers and cutter grade C housed in a rotating mechanism was then field tested. The bit demonstrated a 10% increase in interval drilled compared to the best offset run.

The cumulative impact of these individual enhancements led to a step change in drilling efficiency, reducing bit trips and drilling costs.

A reimagination of a classic drill bit design combined with a unique approach to PDC technology has allowed for a paradigm shift in drill bit durability in hard and abrasive rocks. Several bespoke analyses combined with novel drill bit technologies were developed, deployed, and validated in a new modeling environment. A modern and adaptable design philosophy was validated in challenging reservoir environments across the Arabian Gulf.
Development of High Temperature Resistant Soft Metal Sealing Components in Downhole Tools
Authors: Guo Huijuan , Li Jianghao , Song Xiping , Zhan Guodong, David , Wang Baodong
Published: February 2024

The sealing components plays the role of sealing and pressure resistance of downhole tools, which is a key component that determines the safe and reliable operation of downhole tools. With the development of oil and gas exploitation towards deep and ultra-deep wells, the performance requirements of sealing components for downhole tools are gradually improved. Rubber materials are prone to aging and deterioration in downhole high temperature and corrosive environment, resulting in sealing failure and difficulty in maintaining good sealing for a long time. Soft metal materials have the characteristics of high temperature resistance, high sealing pressure and corrosion resistance. The application of high temperature resistant soft metal materials in petroleum engineering sealing components can better solve the problem of aging failure of rubber sealing components, which is of great significance for ensuring the safety of downhole sealing.

Based on the introduction of the application of soft metal materials in petroleum engineering, this paper studies the refining method of copper-based soft metal materials, and determines the formula of soft metal materials with excellent performance by analyzing the microstructure of soft metal materials. Based on the developed soft metal material, the high temperature tensile mechanical properties test, high temperature elastic modulus test were carried out. The feasibility of using copper-based soft metal as sealing element in petroleum engineering was analyzed, and the soft metal sealing element for expansion pipe sealing was designed.

The research results show that: (1) Metal material seals have been widely studied at home and abroad, and some products have been maturely applied in the market, with good mechanical properties and sealing performance. (2) By adding Ga, Rh, Si and other alloying elements to copper metal, the metal wettability, temperature resistance and elastic properties of the material can be improved, and the sealing function can be realized. (3) The CuRh alloy soft metal material has good deformation ability and high temperature mechanical properties stability. The expansion tube sealing element designed with soft metal material has better sealing performance than rubber material.

The soft metal material sealing element can solve the aging failure problem of common rubber materials in high temperature and corrosive environment. It has good high temperature resistance and corrosion resistance, and can be widely used in the sealing of downhole tools in the development of deep and ultra-deep wells with corrosive media.
Improving Drilling Efficiency Through Carbonates Using Non-Planar Shaped PDC Cutter Geometries
Authors: Alvarez O. , Alalsayednassir A. G. , Othman M.
Published: February 2024

The objective of this paper is to review the lab and field testing of Non-Planar shaped (Polycrystalline Diamond Compact) PDC cutters in challenging applications across diverse Oil & Gas wells, and to demonstrate the tangible benefits in terms of efficiency and cost savings in several fields with high content of carbonates.

Non-Planar Shaped PDC Cutters from three different companies were selected and tested in both laboratory and field settings. Lab tests were conducted to validate the cutters' efficiency, and the best match for the application was determined prior to field testing. Drilling efficiency tests were conducted at both single cutter and full-scale drill bit levels, and field test wells were selected to set a solid benchmark and perform further evaluation.

The Non-Planar Shaped PDC Cutter demonstrated an average of 20% reduction in vertical force required to achieve a given depth of cut, when compared to a legacy cylindrical cutter, in single cutter laboratory tests. In the majority of the cases, the Non-Planar Shaped PDC Cutter's face shapes created a fluid channel behind the cutting ribbon, which decreased frictional losses and promoted cuttings evacuation. The stress in the weight on bit direction was increased, thereby improving fracture propagation.

In field trials, the Non-Planar PDC Cutter demonstrated an ROP improvement of between 15 and 30%, with the highest efficiency gains recorded in carbonates. Cutter durability was assessed by comparing the interval drilled and dull condition, which demonstrated parity compared to conventional round cutters. It can be concluded that the Non-Planar Shaped PDC Cutter Geometries bring tangible drilling efficiency gains that directly translate to reduction in drilling costs.

This paper demonstrates the importance of exploring different geometric PDC cutter designs. It shows that using non-planar cutters improves drilling efficiency at the micro – single cutter level that can be effectively translated to the macro – full PDC drill bit efficiency level. Field testing highlights that these new geometries can deliver tangible ROP performance without compromise to drill bit durability or reparability.
Extraction of Halophytic Oil and its Application in the Formulation Of Oil-Based Mud System
Authors: Khan Munira Akhtar , _ Ayesha , Siddiqui Rida , Lalji Shaine Mohammadali , Ali Syed Imran , Haneef Javed , Abbas Muhammad Adeem
Published: February 2024

Drilling fluid plays a vital role in the complete drilling operations through hydrostatic pressure, cutting transportation, lubrication of conduits, shale swelling inhibition etc. All of these objectives are fulfilled indirectly by managing the drilling fluid properties like rheological properties, filtration properties, thermal stability (for high temperature wells), inhibition properties etc. Oil based Drilling Fluids are more valuable because they are denser than WBM and have more optimized properties too. It is useful to induce very good shale swelling inhibition. But due to environmental concerns, OBM is not recommended to use but this can be controlled by using the greener additives like Halophytic Oil that is being extracted from plants. This study is mainly about the possible use of salt-resistant, non-edible halophytic plants in the oil and gas industry as an eco-friendly replacement. There are different types of halophyte species but in this study we utilized the halophytic specie of Argania Spinosa (Argan). The extraction of Argan oil has done by using cold pressing method. A sample of oil base mud was prepared by adding 158ml of Argan oil as a base fluid. The mud sample underwent pH and stability tests, followed by rheological properties tests, including Gel Strength, Viscosity, Shear Stress, Dynamic Viscosity, Plastic Viscosity, Yield Point and Apparent Viscosity. Filtration test was performed to determine filtrate volume loss and mud filtrate cake morphology. To integrate halophytic Argan oil effectively into OBM systems, our experiments also assessed its compatibility with other OBM additives, including emulsifiers and rheology modifiers. While some adjustments may be necessary to optimize the formulation, our findings suggest that such integration is feasible. This abstract delves into the laboratory experiments that investigate the potential use of halophytic argan oil as a renewable and environmentally friendly component in OBM systems. Halophytic Argan oil, derived from the Argan tree (Argania spinosa), which predominantly thrives in arid and semi-arid regions, presents a compelling option for OBM systems operating in high-temperature, high-pressure, and saline conditions. Its outstanding thermal stability, high antioxidant content, and low toxicity profile make it a suitable candidate for replacing or complementing conventional OBM additives. Halophytic argan oil is a valuable resource with numerous industrial applications. This manuscript explores the extraction of argan oil from halophytic plants, highlighting its unique properties and the challenges associated with its extraction. It also delves into the formulation of an oil-based mud system using halophytic argan oil, a sustainable alternative for the oil and gas drilling industry. This innovative approach aims to reduce environmental impact and improve drilling efficiency.
Enhancing Production Forecasting in Fractured Shale Gas Reservoirs Using a Hybrid ARIMA-EMD-LSTM Approach
Authors: You Junyu , Huang Xiaoliang , Li Yonghao , Yu Qiulong , Ampomah William
Published: February 2024

This study presents a robust machine-learning protocol for predicting production from fractured shale gas reservoirs. The field data of an active shale gas reservoir in Sichuan Basin was utilized to construct and validate the proposed method. The main objective is to establish a framework to rapidly and accurately forecast the production, which aides in assessments of economic viability for shale gas reservoir developments.

This study utilized field production data from a representative shale gas reservoir. Statistical analysis and sensitivity analysis were conducted to characterize the input-output data structure. To train the prediction model, a novel hybrid approach was proposed, combining the Long Short-Term Memory network (LSTM) with the Autoregressive Integrated Moving Average model (ARIMA) and Empirical Mode Decomposition (EMD).Shale gas production is influenced by numerous factors, leading to historical production sequences that exhibit significant nonlinearity and abrupt fluctuations. Consequently, precise prediction using conventional approaches becomes challenging. By applying the proposed workflow, the ARIMA model was applied to filter both linear and nonlinear features from the original production data. ARIMA was utilized to fit and predict the linear components, while the nonlinear components were passed through EMD. EMD was employed to extract Intrinsic Mode Functions (IMFs), which represent local characteristic signals at different time scales within the nonlinear components. Multiple Long Short-Term Memory (LSTM) models were then trained to predict the various IMFs. The hyperparameters of the LSTM models were optimized to enhance performance. The LSTM predictions were combined with the ARIMA results, resulting in a comprehensive production forecasting model. To validate the proposed hybrid method, a comparison was made with an existing approach LSTM. The superiority and feasibility of the ARIMA-EMD-LSTM model were confirmed, as it demonstrated strong generalization ability and increased prediction accuracy by effectively capturing the input-output relationship. It was proved that this framework can enable rapid and accurate forecasting of shale gas production.

This study introduces a novel hybrid ARIMA-EMD-LSTM model, which represents the first application of this approach to fractured shale gas production. The ARIMA effectively separates the linear and nonlinear components of the original data, while the EMD decomposes the nonlinear parts into IMFs. The proposed workflow could enhance the prediction accuracy and intensively extend its feasibility to gas production forecasting in fractured shale reservoirs.
Enhancing the Mean Time Between Failures (MTBF) of Sucker Rod Strings for PCP Systems Running in Harsh Environment
Authors: Vora J. , Jadhav A. , Chauhan Sh. , Kumar Sh. , Jha A. , Chandak R.
Published: February 2024

The primary objective of this paper is to depict the innovative actions taken for the improvement of mean time between failures (MTBF) of sucker rod strings used for progressive cavity pump (PCP) systems deployed in harsh operating conditions in Bhagyam field operated by Cairn Oil and Gas (Vedanta) characterized by high hole deviation, high dogleg severity (DLS), higher pump displacement and high pump torque requirements. The Scope of this paper includes the presentation of challenges faced in smooth operation of PCP systems in harsh environments, detailed root cause analysis (RCA) done for the Sucker rod string failures, actions taken for mitigation of the failures and the resultant improvement in MTBF of Sucker rod strings.

The methodology employed in this study involves creating a deep understanding of the reasons for frequent failure of Sucker rod strings through RCA, design Simulations in PC Pump Software by C-Fer and actions taken to improve the sucker rod string performance and mitigate failures. Following were the prominent types of failures that were observed in the Sucker rod strings:- 1. Sucker rod Snap in plain / guided rods 2. Sucker rod thread wash 3. Sucker rod Coupling Snap.

To increase the MTBF of sucker rods PCP systems, various initiatives and actions have been successfully implemented in the field, including the following: 1. Analysis and improvement of sucker rod handling practices. 2. Optimization of rod guide strategy and rod guide material selection. 3. Analysis of the optimal combination of rod size, tubing size, and pump to minimize rod Tubing friction and pressure loss 4. Evaluation of the historical failure trends of rods to enable pre-emptive rod changeout. 5. Collaboration with vendors to develop on-site rod guide molding. 6. Revising the Sucker rod design philosophy to increase the number of guides per rod 7. Periodically conducting coupling shifting jobs in PCP wells 8. Standardization of Variable Frequency Drive (VFD) trip Settings

By implementation of the above actions, we successfully minimized the stress and fatigue experienced by the rods during operation, leading to improved reliability and extended service life. By enhancing the MTBF of sucker rods, the reliability and overall efficiency of PCP systems were increased, resulting in reduced downtime, improved production efficiency, and decreased maintenance costs. Notably, the MTBF of the Sucker rod String for Bhagyam PCP Wells increased about 3 times in 1 year of operation.

By achieving a remarkable 80% reduction in rod failures year on year, this research contributes valuable insights into enhancing the overall efficiency and reliability of PCP systems deployed in complex oil field environments.
Reuse of Abandoned Hydrocarbon Wells and Reservoirs for Geothermal Energy
Authors: Nassan T. , Baganz D. , Alkan H. , Amro M.
Published: February 2024

Drilling costs account for the majority of geothermal project costs. Therefore, it makes sense to reuse abandoned gas and oil wells supported by in-situ heat flux. This study examines the extent to which abandoned hydrocarbon wells as well as depleted reservoirs can be used for geothermal heat recovery and/or power generation using different circulation fluids, the retrofit opportunities and challenges to make them suitable for geothermal energy and assess both based on preliminary economical comparison.

We numerically investigated open and closed geothermal systems using the characteristics of depleted German oil and gas reservoirs as examples. We generated the heat and material balances of a depleted gas reservoir with a 3D reservoir simulator with abandoned wells for injection and production. For selected wells, we also calculated heat transfer in a closed-loop geothermal system for different system configurations. In each case, we evaluated the timely performance of heat extraction. The calculated data were used for a preliminary economic evaluation that included the cost of retrofitting the wells and monitoring the critical process parameters.

Our calculations confirmed the advantage of using depleted gas reservoirs as open geothermal systems, provided that the thermal capacity of the reservoir is sufficient. Another obvious advantage is that injection and production wells can be retrofitted at relatively low cost; only the production wells must be isolated. Wellbore flow containing impurities from the reservoir appears to be one of the potential hurdles. In case of lower permeability petrophysics, the connection between injection and production wells should/could be made either by hydraulic fracturing or by hydro-shearing of existing fractures in the rock, which could increase the capital cost. In closed loop systems the heat transfer from the formations is limited. Even in the case of appropriate retrofit of the wells for coaxial design for using as heat exchanger, the sustainability of heat extraction is limited allowing for direct heating applications rather than economic power generation. The economic and energy analysis were performed to assess and compare the thermo-economic performances of both systems.
Improving Oil-In-Water Treatment by Optimization of Production Chemicals
Authors: Aliti Liridon , Andersen Simon I.
Published: February 2024

The removal of oil droplets from water heavily depends on the ability for these to coalesce into larger drops to overcome size limitation of equipment such as centrifuges, hydrocyclones, gas flotation etc. The composition of PW is a mixture of oily compounds, inorganics from the formation and production chemicals. Chemicals have a significant impact on the stabilization of oil droplets but variations in salinity also plays a role. The repulsion of droplets has detrimental effect on the treatment. In this paper we aim to quantify this in order to develop optimization tools.

Methods, Procedures, Process: The quantification of droplet coalescence and impact of chemistry is obtained through specially designed microfluidic chips. Droplets are recorded using high speed cameras. Using image analysis coalescence efficiency is quantified. Partitioning of chemicals between water and oil which is affected by both salinity and oil type and measured by capillary electrophoresis. This is analyzed using capillary electrophoresis. Real PW samples and chemicals are obtained from offshore Denmark. Coalescence events are recorded while varying oil type and also diluting the PW to understand which constituents lead to stability of drops and hence potential adverse effects in water treatment.

Results, Observations, Conclusions: The fundamental Bancroft´s rule describes that the component favorable dissolved in one phase will stabilize droplets in this continuous phase. Hence compounds primarily soluble in water stabilize oil droplets in the water treatment system, and can lead to poor water quality - potentially having an adverse effect on sizing of equipment. Accordingly specifically water-in-oil (WiO) emulsion breakers can have a detrimental effect when overdosed, as more is not better. When different water streams are commingled before treatment there might be potential cases where one stream despite its apparent low content of oil-in-water (OiW) can stabilize droplets in another stream. We present data based on microfluidics and analysis of partitioning coefficients using a variety of real PWs and production chemicals from O&G production in the Danish North Sea. This clearly indicates that the main issue is related to water constituents, but that oily polar components have a large impact as well on stability. The qualitative information is linked to quantification using the hydrophilic Lipophilic Deviation theory which can then be used to optimize potential scenarios of synergistic and antagonistic effects of chemicals and PW constituents on water quality. Discussion will also aim understanding mixing rules for quantification in multicomponents mixtures based on surface chemical insight.

Novel/Additive Information: We apply both novel microfluidics and novel analytical techniques for production chemical partitioning measurements.
A Graphical User Interface for Hard Rock Drilling Optimization System
Authors: Atashnezhad A. , Al Dushaishi M. F. , Hareland G.
Published: February 2024

The objective of this paper is to present a novel graphical user interface for optimizing drilling operations in hard rock formations. The scope of the study includes presenting the developed Python graphical user interface (GUI) for a hard rock Drilling Optimization System (DOS) that incorporates various models and algorithms to simulate the rate of penetration (ROP) and optimize drilling parameters. The DOS was applied to real-world hard rock drilling data from a deep geothermal well in the Utah FORGE (Frontier Observatory for Research in Geothermal Energy) site. To develop an interactive interface for users, the DOS for hard rock formations was created using the open-source Python library, tkinter. The DOS consists of various hard rock models including PDC ROP, PDC bit wear, drillstring vibration, PDC cutter temperature, mechanical specific energy (MSE), and a differential evolution algorithm (DEA). By integrating these models into the GUI, users can simulate drilling operations, optimize drilling parameters such as weight on bit (WOB) and revolution per minute (RPM), and determine the wear constant of a specific PDC bit. This interactive interface enhances user engagement and facilitates efficient drilling optimization. The study observed an improved ROP and reduced drilling time by optimizing WOB and RPM. The conclusions drawn from this study emphasize the importance of specialized techniques and tools for drilling in hard rock formations and highlight the potential for more efficient and sustainable drilling operations in the geothermal industry. The integration of various models and algorithms within the GUI DOS provides a novel, and practical approach to simulate and optimize drilling parameters. The results and conclusions of this research contribute to the state of knowledge in drilling practices, particularly in the context of optimizing drilling operations in challenging hard rock formations.
Integration Between Different Hydraulic Fracturing Techniques and Machine Learning in Optimizing and Evaluating Hydraulic Fracturing Treatment
Authors: El Khouly I. , Sabet Ahmed , El-Fattah Mahmoud A. A. , Bulatnikov M.
Published: February 2024

Fracture geometry and conductivity are critical parameters for fracture treatment optimization, especially in cases that close to unwanted zones either water-bearing or gas zones. This study investigates the Artificial Neural Network (ANN) model for hydraulic fracturing optimization. The workflow begins with an integrated ANN model, then sets of variable fracture parameters and formation rock properties were utilized for training and testing the ANN based on the most appropriate activation function, the number of hidden layers and the number of neurons.

The ANN model considers a 59 real field data of hydraulic fracturing treatments across the western desert of Egypt. The proposed ANN trained based on pressure transient test analysis that was conducted on the real field data. The available data was divided as 70% for training, 15% for validation, and 15% for testing. The optimum number of hidden layers and neurons was achieved after several trials.

The proposed ANN model result was promising as compared with the common fracture simulation software. The cross plot of the actual fracture geometry parameters versus the predicted ANN outputs showed a good match with the correlation coefficient (R) for the whole data is 0.93. Then the relative importance of the ANN input parameter on the fracture geometry optimization was employed by the Garson method. The result of this work shows the potential of the approach developed based on the ANN model for predicting the fracture geometry.
Completion Optimization by Fracture Mapping Using Realtime High Resolution Resistivity Imaging Tool in Horizontal Wells of Western Offshore India
Authors: Bagga Pawandeep Singh , Chitroda Chandrajyoti
Published: February 2024

The Western Offshore Basin is a significant geological region located along the western coast of India, extending from Gujarat in the north to Maharashtra in the south. It encompasses a vast expanse of the Arabian Sea, where the continental shelf gradually gives way to the deep oceanic waters. This basin is of immense importance in the field of hydrocarbon exploration and production due to its rich reserves of oil and natural gas. The petroleum industry finds horizontal wells highly appealing because they offer a promising solution for enhancing both production rates and recovery efficiency. By drilling horizontal drain holes, the number of wells required to exploit a field can be reduced significantly, thanks to their extensive reservoir exposure. Nevertheless, it is crucial to address the challenges related to completing these wells to extend their operational lifespan.

To optimize oil recovery and prolong the lifespan of a well, horizontal wells need to be completed with an optimal number of Inflow Control Devices (ICDs) that have appropriate Flow Resistance Ratings (FRR). This setup ensures the even distribution of flow along the horizontal well in formations with high permeability. It also helps mitigate early breakthrough at the heel for thin oil formations and delays water breakthrough at locations with high permeability in heterogeneous formations.

Advanced high-definition Logging-While-Drilling (LWD) electrical imaging services has brought a significant breakthrough in subsurface characterization during drilling operations. This cutting-edge technology combines the power of LWD measurements with high-resolution electrical imaging capabilities, offering unprecedented insights into the geological formations surrounding the wellbore. Real-time images are valuable for detecting wellbore stability problems such as drilling-induced tensile fractures and breakout in time to mitigate the problem. Sedimentary steering is also possible with real-time images, letting you keep the wellbore in the best part of the formation.

This paper aims to examine the progress of modern technology in high-definition logging-while-drilling electrical imaging tools. These tools gather micro resistivity data along the entire circumference of the borehole while the bottomhole assembly (BHA) is rotating. The obtained micro resistivity image from LWD, after undergoing processing, effectively revealed the existence of fractures. These fractures were subsequently classified into various zones to determine the optimal ICD completion based on the density of fractures. Geological features such as natural fractures and dissolution features such as vugs are clearly resolved and captured by the high-resolution image acquired using LWD Electrical Image logging tool.
Real-Time Automated Formation Evaluation Using the Integration of Logging While Drilling and Advanced Cuttings Analysis
Authors: Alqunais A. E. , Solial A. J. , Ferriday T. , Collett E. , Taher A.
Published: February 2024

Real-time formation evaluation is performed utilizing data acquired in the field from logging-while-drilling (LWD) tools and mud-logging data equipment. The data is then interpreted in the office by petrophysicists and log analysts. Unlike traditional log interpretation analysis, automated log analysis using statistical models provides continuously improving results based on trained and supervised models. Most automated log analysis approaches utilize historical data and incorporate multi-well data to improve the petrophysical evaluation. The objective is to reduce the evaluation time and reduce uncertainties based on trained models.

Real-time LWD and surface data logging are primarily used for formation evaluation and well placement in high-angle and deviated wells. Log analysis is usually performed by petrophysicists and is not in actual real time. Providing the interpretation in actual real time provides important data for geologists, well placement engineers, and drilling engineers to improve the reservoir contact and productivity in addition to operational cost reduction.

A selection of models has been used for automated lithology predictions. Five logs have been used in total utilizing basic LWD data (gamma ray, density, resistivity, photoelectric, and neutron-porosity measurements). In addition to the LWD data, advanced cuttings analysis has been performed on site in real time on multiple wells. X-ray fluorescence (XRF) provides elemental data while X-ray diffraction (XRD) provides direct mineralogy measurements.

The automated lithology interpretation provides quick assisted lithological interpretation and quantifies uncertainties with minimal human input. Basic LWD data were used for the automated lithology interpretation. The predicted lithology was verified against interpreted mineralogy from XRF and direct mineralogy from XRD measurements. Simulation of the results and the real-time QC process are very promising. Quality control processes were followed for the data acquisition where XRF computed gamma ray was used to verify the depth control for XRF and XRD data with reference to the LWD measurements.

Real-time automated log analysis provides a step change in formation evaluation, providing critical information to well-placement and drilling engineers as well as an automated quality-control measure for data acquired in real time.
Surface and Subsurface Development Strategy of a Carbonate Stringer with Halite Production in Southern Oman
Authors: Kindi I. Al , Bahluli M. Al , Agrawal P. , Alawiya B. Al , Sulaimi G.
Published: February 2024

Stringer reservoirs in south of Oman are carbonate bodies encapsulated in thick zones of Ara salt. The pressure in these reservoirs is varying from lithostatic to hydrostatic regime. Halite production in field HL-3A has been a major challenge throughout the years of production; hence, a thorough investigation was needed to tackle the issue and come up with a strategy to decrease salt migration to the wellbore. Fluid sampling and pulsed neutron logging (PNX) were done to study salt content and free water fraction variations over the well production timeline. Additionally, well testing was performed to identify the suitable offtake envelope to control halite production by monitoring wellhead pressure, water cut, and salt concentration at different choke sizes. Such an approach led to a reliable well offtake envelope to constraint plugging issues caused by salt; the strategy was more sustainable than previous short-term strategies, like regular freshwater flushing. Plus, it contributed to lowering field development cost by 30%. This paper describes actual experience shared from HL-3A reservoir management and learnings. The approach could be beneficial for comparable depletion cases elsewhere and valuable in deferment reduction, field development planning, and halite production management steering to operational excellence.
Enhancing Fluid Characterization in Oil and Gas Exploration: A Global Approach to GOR- Composition Relationship
Authors: Suman S. , li Z , Satapathy P.
Published: February 2024

This research introduces a fluid characterization tool designed for the oil and gas industry, focusing on improving the understanding of fluid composition by correlating Gas Oil Ratio (GOR) and fluid properties.

The tool was developed using a dataset that includes GOR values ranging from 1000 to 6000 scf/stb, bubble point values between 3500 and 5500 psia, and API gravity values from 40° to 55°. This dataset was collected from over 40 wells in the Delaware Basin, ensuring precision and avoiding the manual errors associated with traditional analog tools.

Traditionally, the process involved finding an analog well, a step prone to errors due to variations in proximity and fluid properties. The tool, however, establishes correlations between GOR, fluid properties, and relevant data points, creating an algorithm for deriving reservoir fluid composition. This composition seamlessly integrates into the Global Fluid Characterization (GFC) Model.

The fluid characterization tool proved to be accurate and reliable in characterizing fluid composition. It provided immediate and trustworthy results through its user-friendly interface. With only GOR values, professionals can get a good estimate of reservoir fluid composition. The tool eliminated the need for laborious and expensive laboratory analyses, making it a valuable time-saving and cost-effective solution.

The dataset used for its development, encompassing a wide range of GOR from 1000 scf/bbl to ~5000 scf/bbl. Additionally, the capability of the tool can be enhanced as new wells are incorporated in the Global Fluid Characterization (GFC) Model. It enables us to use compositions for various purposes like making informed decisions in reservoir simulations, well testing, and production activities.
Learnings from Inflow Control Devices (ICD) Design Optimization Utilizing Dynamic Reservoir Simulation Modeling
Authors: Hidayat W. , Karim M. Abd. , Albassam M.
Published: February 2024

The objective of this paper is to present learnings from designing inflow control devices (ICD) of numerous wells at reservoirs with gas cap with various settings. Key aspects and an efficient ICD design workflow will be presented. The evaluation is based on the application of nozzle ICD for single lateral horizontal well. A synthetic simulation model is utilized to demonstrate example cases.

A horizontal well installed with ICD completions improves well performance by equalizing production along the horizontal section to delay water/ gas breakthrough for an oil reservoir with gas cap and aquifer.

We utilized an in-house reservoir simulator with advanced complex well options. The first step is to develop an ICD completion design workflow, which includes understanding reservoir permeability heterogeneity, its magnitude and well flow behavior under open-hole completion. At well level, this step is to estimate future major gas and water contribution. Optimum well rate is sensitized for the ICD design. The next step is to focus on ICD design optimization which includes numbers of ICD requirements and compartments, ICD choking.

The performance of horizontal well placed under a gas cap was analyzed. An early gas production easily occurs especially for well with high production rate. Controlling gas and water production showed an improvement on oil recovery. We developed the workflow of an ICD completion design optimization for the evaluation. Simulation model with different reservoir properties vertically were created for ICD design case. The ICD design optimization cases with combination of these two factors are evaluated to identify conditions for ICD installation that provide best benefits. Results showed that installation of ICD provides good performance improvement and more even gas oil contact and water oil contact movement toward the wellbore.

The ICD design workflow provides a guideline to do the ICD design systematically utilizing reservoir simulation model for an oil rim reservoir. Learnings obtained from the results provide an understanding on the optimal conditions for ICD installation with the goal to ultimately deliver long-life wells while controlling water and gas production in different levels of reservoir heterogeneity and well lengths.
Comparison of Different Type of Acid Diversion in Acid Frac Stimulation and their Effectiveness to Well Production
Authors: Aldawsari Mudhish A. , Ahmed Mutaz M. , Alshoura Basem F. , Wijaya Rio , Vossen Johannes
Published: February 2024

Acid fracturing has been commonly used to stimulate carbonate formation. Presented in this paper are different types of acid diversion techniques used for one such case. This acid diversion is intended for better acid distribution across long stimulation target intervals. The different types of acid diversion techniques that were used include crosslinked acid, viscoelastic based acid diverter, solid and self degradable fiber acid diverter, and Associative Polymer / RPM based acid diverter. The paper is comparing the effectiveness of the diverter and also the effect of the acid diversion to the well production.

The examples that were selected for analysis are producing from the same formation and located relatively close to each other to enable fair comparison. Acid diversion effectiveness is measured based on pressure increase that was observed during the acid fracturing treatment. As the length of stimulation target intervals are different between stages and wells, the pressure increase was then normalized to the length of the perforation / open hole interval. Other than pressure increase, well deliverability post acid stimulation was also compared between wells and was normalized to the reservoir pressure – flowing well head pressure (from available data during well test post acid frac stimulation). These two parameters: normalized pressure increase from acid diversion and normalized maximum gas rate during the well test were then graphed to see the trend between these two parameters.

Different types of acid diversion give different pressure increases during acid diversion. In general, the higher the pressure increase, the higher the maximum gas rate. There’s an optimum point of pressure increase from acid diversion that correlates with maximum gas production, which is observed from the wells that were studied.

The approach described in this paper is intended to provide the guidance on selecting the type of diverter for acid frac stimulation for better well delivery. This approach is formation specific and the completion type needs to be accounted for when designing similar acid fracturing.
Case Studies in Integrated Fracture Design and Well Spacing Optimization in Shale
Authors: Fowler G. J. , McClure M. W. , Singh A. , Irvin R. , Ratcliff D. , Ponners C. , Rondon J.
Published: February 2024

Well spacing and hydraulic fracture design have an enormous impact on the economic performance of wells in shale. Key design parameters include: (a) horizontal and vertical well placement, (b) stage length, (c) cluster spacing, (d) cluster shot count, diameter, and phasing, (e) proppant and fluid type, (f) proppant and fluid volume, and (g) injection rate. Case studies from the Bakken, Delaware Basin, Midland Basin, and Montney shale plays are presented. Numerical simulation is used to evaluate alternative options and maximize economic objectives.

Numerical simulations are performed with a fully integrated hydraulic fracturing and reservoir simulator. Rather than performing a ‘handoff’ between two different codes, the simulator solves all governing equations (for multiphase flow, crack propagation, non-Newtonian fluid, and proppant transport) in a single system of equations and consistent mesh (wellbore, fractures, and matrix). The workflow involves: (a) construction of an initial model, (b) calibration to field diagnostics, (c) and economic maximization with an automated optimization tool. Diagnostics include: (a) fiber DAS and DTS, (b) microseismic, (c) geochemical analysis, (d) interference testing, (e) downhole imaging, (f) production data, and (g) pressure monitoring wells.

Field observations suggest significant variability in fracture geometry between basins. Height growth varies dramatically and is driven by the vertical stress profile. In one dataset, recently developed ‘viscoelastic stress relaxation’ derived stress profiles are much more consistent with fracture geometry observations than the classical Eaton’s approach. Fracture length and effective toughness show a modest degree of variability between formations. Once calibrated, the models enable economic optimization. Optimization runs suggest opportunities to improve NPV (net present value) or DROI (discounted return on investment) from 10-60%. For some parameters (such as job size and well spacing), optimization results vary significantly depending on the objective function (either DROI, NPV, or NPV/section, with or without including the cost of land). The price of oil and gas also have a major impact on the optimal design. For other parameters, such as landing depth, stage length, and perforation cluster design, optimization results are relatively robust to the objective function and economic assumptions. We show how differences between basins and differences in economic inputs and objectives lead to significantly different optimal frac designs.
A Scalable Numerical Solution Method for Fine Scale Compositional Simulation
Authors: Wang Baohua , Xu Mingyuan , Li Qiaoyun , Li Hua , Jia Han , Fan Tianyi , Wu Shuhong
Published: February 2024

Nonlinear iteration is a very important part of reservoir numerical simulation. If the iteration steps can be reduced, the speed of the iteration and the reservoir numerical simulation will be helped greatly. In this study, a self-equilibrium Newton method has been explored for nonlinear system of compositional simulator, which is composed of inexact Newton method, non-negative constraint line search method of molar concentration and automatic time step selection method. Furthermore, a multilevel preconditioning operator and domain decomposition method are adopted to realize parallel computation of the simulation. Comparison with traditional methods, numerical tests indicate that the self-equilibrium Newton method can improve the overall efficiency of the nonlinear system of the component model.