bluuebunny/crossref_metadata_2025 huggingface dataset:
Casing Elongation Study During Cementing Job on Long Casing Strings
Authors: Corona Mauricio , Ruzhnikov Alexey , Sebbane Slimane
Published: January 2020

This study describes the process followed to explain and understand the mechanical blockage in the flow path observed while displacing the cement slurries in long casing strings set with short rat holes. In most of the cases, those blockages ended with amount of cement left in pipe and significant remedial works.

All the incidents were investigated involving casing design experts, cementing specialists and data analysts to understand the root causes. Mud logging unit, cementing and rig sensors data from several cementing jobs were analyzed in an integrated and holistic approach. Different software's were used to simulate and prove the theory that total elongation of the casing was enough to exceed the rat hole length bringing the casing in contact with the bottom of the well, and therefore blocking the flow path.

In all the incidents, the issue was observed at the beginning of the slurry displacement stage where the entire volume of the cement was still inside the casing. Other possible causes of blockage (cement contamination, mechanical failures, loss control material,…) were also checked and ruled out.

Hookload data was available to be analyzed whenever a conventional wellhead was installed, and the casing was held on the elevators during the cementing job. However, in some cases this information was not available as a compact wellhead was used. For those cases, it was necessary to drill out the shoe track using LWD to detect the location of casing shoe.

Recommendations were made to add new loads the current casing design. Results will define the minimum rathole length and the maximum tension at surface experienced by the casing during the cementing job in both static and dynamic conditions. Also, it is important to properly estimate the rathole the physical measurement of the casing joints in the tally can carry measurement errors.
From Geophone to DAS: Evolution of Q Estimation
Authors: Pierre Bettinelli , Le Calvez Joel
Published: January 2020

The Schlumberger Oilfield Glossary states that Q is ‘the ratio of the peak energy of a wave to the dissipated energy. As waves travel, they lose energy with distance and time due to spherical divergence and absorption. Such energy loss must be accounted for when restoring seismic amplitudes to perform fluid and lithologic interpretations, such as amplitude versus offset (AVO) analysis’.

In surface seismic, we face the problem of characterizing the effect of anelastic attenuation on the seismic signal during propagation. The Q-factor is sought after because it is useful for amplitude analysis, phase compensation and for improving resolution. Though the Q-factor can be estimated from surface seismic data, traditionally the Q-factor is extracted using acquisition methods relying on accelerometers and/or geophones during borehole seismic surveys such as zero-offset vertical seismic profile (VSP), 2D walk-away VSP (2D WVSP) or 3D VSP campaigns. The reason why borehole seismic is the preferred option to estimate the Q-factor is because VSP surveys sample the wavefield by sensors in-situ (depth control), and also it gives robust measures using the direct arrivals. The Q-factor can then be, used to derive a Q-filter, which can be applied to the surface seismic to diminish the effect of anelastic attenuation and can compensate for the loss of amplitude and frequency in the data as well as to correct for the phase difference.

Several methods of Q-factor determination may be used, each with its pros and cons (e.g., continuous (log) Q-factor using spectral ratio, multi-spectral ratio, continuous interval Q-factor).

With recent advances in the fiber optic field, we anticipate (and already see) a surge in VSP surveys being acquired with distributed acoustic sensing (DAS) or heterodyne distributed vibration sensing (hDVS) as this acquisition method is extremely cost-effective from a deployment point of view and required acquisition time.

We demonstrate that with minimum work, one can provide a robust Q-factor estimation using fiber-acquired datasets.
Integrated Approach to Develop Mega-Projects: Challenges and Risk Strategies
Authors: Akimova Irina
Published: January 2020

The ambition of this paper is to provide description of integrated approach that was successfully applied to develop mega-projects in Russia: from development of Yamal, the biggest gas provience in Russia and in the world with several unique super mega-fields located in the area, to the recent ahead-of-time Arctic development in Russia.

Russian oil and gas sector is characterized by high concentration of mega, super-giant and giant fields in two relatively small areas – Yamalo-Nenetskiy District as a gas provience and Khanty-Mansiysk District as an oil provience, which are very remote from the mainland with lack of infrastructure at the time when mega-projects were just a plan and hazardous climate conditions. Most of the territory of the Yamalo-Nenetskiy district is located above the Polar Circle that makes its development so challenging. The aim was not only to develop these oil and gas mega-projects and its infrastructure but to create and maintain high standard of living for local communities and indigenous nationalities. And this goal was successfully achieved by using special integrated approach. This special integrated approach combines territorial, industrial and mega-project joint planning and performing along with cost management of these projects including special agreements between regions and companies, trend that is very special still to the international energy market and this practice was followed by a number of international energy majors already. For the latest and even the most complicated mega-project now, Russian Arctic development, new updated integrated approach was elaborated that combines so called support zones of development, infrastructure development and emerging technologies development. New legislative framework and fiscal incentives along with special investment contracts were introduced to booster this project development and to attract investments. All the zones of development are considered as one project with common planning, financing, cost management and all the zone’s projects implementation.

Yamalo-Nenetskiy District (YANAO) contributes 18% to the world’s gas proved reserves and 65% to the Russia’s total gas reserves. As for the beginning of 2018, 236 fields of hydrocarbons were discovered in YANAO, from them 89 fields are under development now and 147 fields are under exploration works. Main area of gas production in YANAO is in Nadym-Pur-Taz oil and gas provience where world’s biggest concentration of super giant mega fields are located – Medvejie field, Urengoy field and Yamburg field. These fields were put into operation in 1970s-1980s and mainly in the declining production level now. Since the beginning of production in Yamalo-Nenetskiy District, totally 12% of initial gas reserves, 5% of oil and 2% of condencate were extracted. To maintain production level and to secure export contracts, new centers of production are under development now. Yamal’s peninsula development started in 2012 with the launch of the giant Bovanenkovo field.
Should We Waterflood Low Permeable Reservoirs?
Authors: Naugolnov Mikhail , Sednev Alexey
Published: January 2020

The aim of work is to ensure that it is possible to realize effective water injection system for low permeable reservoir with hard-to-recover deposits and an average permeability less than 1 mD. The results of oil field pilot works and computer modelling are shown and compared.

The novelty of the work are rare enough field experiments in water injection system organization in low permeability reservoirs and injection system full comprehensive studding. Some empirical correlations between the values of permeability, heterogeneity, sweep efficiency and injection effectiveness for different well completion types will help reservoir engineers to select the best well pattern and to decide do we need any injection or not without labor intensive actions.
Effect of Temperature on Fines Migration during Water Disposal
Authors: Wang Yamin , Yu Muhan , Le-Hussain Furqan
Published: January 2020

Recent experimental studies show that fines migration effect in sandstone rocks is more prominent at higher temperature. However, increased fines migration is generally attributed to temperature dependant zeta potential. In this study, laboratory studies were designed to investigate if mineral dissolution induced more fines migration at high temperatures.

In this experimental study, Berea sandstone core samples are used and performed single-phase flooding experiments at three temperatures, 25°C, 50°C and 70°C. Core samples are characterized using X-Ray Powder Diffraction (XRD) and X-Ray Fluorescence (XRF) before the flooding experiments. Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) analysis are also conducted to identify the changes of rock surface before and after the flooding experiments. All core samples are subjected to single-phase injections of water at salinities 40, 10, 2.5, 0.5 and 0g/L NaCl. To calculate permeabilities, pressure drops are recorded using pressure transducer during the flooding experiments. The produced water is collected and used to measure the concentration of produced fines. Inductively coupled plasma-optical emission spectrometry (ICP-OES) is applied to analyze the types of produced minerals in each experiment.

The analysis of produced water showed that an increase in Ca ions at 50°C and 70°C. Chemical reation led to dissolution of carbonate minerals increasing pore opening. Therefore, the permeability damage due to fines migration is less pronounced at high temperatures.
Safaniya Lagoon Biodiversity Sanctuary
Authors: Al-Sinan Ali , Al-Juman Moayad
Published: January 2020

Among the many goals of environmental management in Saudi Aramco, protection of special environmental areas is recognized as high priority to both the company and the Kingdom of Saudi Arabia. In line with this objective, Safaniya Onshore Producing Department (SONPD) designated Safaniya area sea water lagoon as Biodiversity Area. The area is estimated to be 6 km2 peninsula, which is located in the north east of the Safaniya Producing Plant, where undisturbed native flora combines with a pristine shallow sea water lagoon, and provide a safe place for land wildlife (foxes, rodents, reptiles), marine wildlife (turtles, shrimps, fish, mollusks) and birds (flamingos, seagulls, etc.). Establishment of the Safaniya Lagoon started with surveying Safaniya and Tanajib Area, in collaboration with Saudi Aramco Environmental Protection Department (EPD) to select the most suitable region for biodiversity development. An establishment procedure was followed to secure the area with fences to limit the accessibility and prevent improper usage. A signboard was installed to identify the area as a sanctuary, forbidding entrance or any type of land use. Site development included mangrove plantation, already existing trash clean-up, and observation any type of waste dumped in the area, to ensure no contamination or danger to the habitat in the lagoon. The department successfully cooperated with Saudi Aramco EPD to plant more than 9,000 mangrove seedlings at the first two years of development. SONPD in collaboration with Society of Advocates and Volunteers for the Environment (S.A.V.E) invited employees with their respected family members to participate in a biodiversity beach clean-up campaign. The campaign helped collect more than 300 kg of waste, consisting of plastic bottles, old ropes, wood, and other waste materials. SONPD, along with its partners and programs, has now established the Safaniya Lagoon ecological and biological diversity sanctuary as a permanent refuge, with in-place protection and future mangrove planting events planned, the area is expected to expand in biodiversity with native flora and fauna, and expand a natural breeding and hatchery. During the winter season, migratory birds — such as flamingos and Amur Falcons, with flyways that pass over Safaniya Lagoon — are seeking warm weather and abundant food supplies. Creation of biodiversity is just the beginning of further area development. The next phase of sanctuary enhancement will be reutilization of tertiary treated wastewater for trees, which will form a wind barrier for mangroves.
De-Risking a Large-Scale Unconventional Gas Field Development
Authors: Khan Farooq , Elphick Matthew
Published: January 2020

Unconventional gas developments in the Middle East are relatively new, compared to the established shale developments in the US. The Middle East developments are generally owned or controlled by a single entity, e.g. the national oil company, rather than the model often seen in the US of multiple operators focused on their particular ‘block’. This can lead to a different approach to the full field development (FFD), with more emphasis needed on de-risking projects, particularly during their early stages. This de-risking process is essential to limit the exposure of the single owner to the inherent uncertainties of an unconventional development as the scale of the project increases.

This paper considers multiple areas of uncertainty and risk associated with an unconventional gas field development. From the necessity for clear project drivers and team alignment, through to the uncertainties of well production and water management, risks are identified with recommendations to help projects avoid pitfalls and manage the inherent risks of developing a large unconventional field in the Middle East. The paper concludes that a Middle Eastern project can't, in all cases, simply adopt the practices used in the US. The project may choose to take guidance from the US but since the operating environment is different, the risks, and therefore management of risks, will in many cases need to be addressed differently.
State-of-the-Art Review of Lost Circulation Materials and Treatments – Part II: Probability and Cost Analyses
Authors: Alkinani Husam H. , Al-Hameedi Abo Taleb T. , Dunn-Norman Shari , Al-Bazzaz Waleed H.
Published: January 2020

Lost circulation is a major problem in drilling operations. As the drilling environment is getting more complicated nowadays, the problem of lost circulation can lead to a significant additional non-productive time (NPT). The objective of this work is to provide in-depth insights into probability and cost analyses of the current lost circulation materials and treatments used around the world. This is the second part (Part 2) of the state-of-the-art lost circulation materials and treatment, the other part (Part 1) focuses on the trends and uses.

Lost circulation data of more than 2000 wells drilled worldwide were gathered from many sources such as daily drilling reports, final well reports, technical reports, petroleum literature, etc. The treatment data were classified based on the type of loss as treatments for partial, severe, and complete loss. Descriptive data analytics and visualization tools were used to analyze the data. A dashboard was created to help to analyze the data.

The results of this work revealed that there are simply two criteria to be used in the decision-making process to choose the best lost circulation treatment. The first one is that the treatment has to have a high probability of success, and the other criterion is that the treatment has to have a relatively reasonable cost based on the type of loss. In different words, optimization has to be conducted to choose treatments based on the type of loss. However, some treatments with a high probability of success may have a low number of usage which might be the reason behind the high probability of success. Thus, careful attention should be given for the number of uses of each treatment when calculating the probability. On the other hand, some treatments have a low probability of success and high cost, which indicates that the high cost does not always correlate with a high probability of success. In addition, the type of loss will play a major rule in selecting the treatments since some treatments are too expensive to be applied for partial loss as an example, and usually, other options are available.

In short, this study will provide clear insights into the cost and probability of the state-of-the-art lost circulation treatments and materials used in the oil and gas industry. The recommendations provided by this study can be utilized to make better future decisions to treat lost circulation.
Environmentally Acceptable Shale Inhibitors for High Performance Water-Based Muds
Authors: May Preston , Deville Jay , Miller Jeffrey , Burrows Kim
Published: January 2020

The water reactivity of clay-containing shale minerals remains a long-standing problem when drilling wellbores with water-based fluid systems. Complicating this issue, the environmental effect of chemical additives used in water-based drilling fluids continues to receive heightened scrutiny in various regions across the world. This study addresses these challenges by expanding the molecular toolbox of environmentally friendly additives that are available to manipulate shale reactivity. To this end, a shale inhibitor package is introduced and discussed that leverages chemical synergy to impede the uptake of water in shale minerals while also increasing the structural integrity of shale cuttings. The main component, a natural-based hybrid organic/inorganic inhibitor blend, is highlighted.

Simple fluids systems were prepared with potassium-based brines and combined with shale inhibitors for initial shale erosion screening experiments. These simple fluids isolated the shale inhibition effects of the inhibitors of interest and excluded the possible influence of additional chemical additives typically found in drilling fluids. Subsequently, fully formulated, water-based drilling fluids were prepared with these inhibitors and compared to fluids with traditional inhibitors. These fully formulated drilling fluids were characterized by rheological testing, fluid loss, shale erosion, accretion, and linear swell testing.

An inhibitor combination of a hybrid organic/inorganic inhibitor blend, along with a nitrogen-rich oligomeric hydration suppressant, was determined to be the most effective inhibition mixture in simple fluid screening. The dual mode of action of the two inhibitors, disparate in both molecular size and chemistry, likely achieved optimal interfacial shielding on the clay minerals to effectively diminish the rate of reaction with water. More importantly, the shale inhibition was successfully translated to fully formulated fluid systems without affecting rheological properties or diminishing fluid loss control. The results achieved were comparable to a current high-performance, synthetic-based shale inhibitor; however, the new shale inhibitor package features a more favorable environmental profile.

Natural-based materials and their derivatives are continually revealed to contain useful properties, particularly for water-based drilling fluids. In this study, high-performance functionality and environmental friendliness were united with an innovative natural-based hybrid organic/inorganic inhibitor blend that is believed to function by encapsulating shale minerals. In addition, a synergy was discovered between hybrid organic/inorganic inhibitor blends and nitrogen-rich oligomeric compounds. Ultimately, the materials developed have achieved yellow environmental ratings in the North Sea and have been successfully validated in field applications in Norway.
Effectiveness Well Integrity Management for Casing Leak Detection Utilizing Temperature Profile in Offshore Oil Field
Authors: M. Al-Dhafeeri Abdullah , Fouad Abo Zkery Shebl , A. Al-Aklubi Sultan , Ahmed Al Sdeiri Saad
Published: January 2020

As part of well integrity and safety campaigns in offshore fields, downhole Temperature surveys were obtained as record of temperature values measured with respect to depth steps (logs) in a well. The downhole condition for each well is an essential factor to determine the well status and to prevent a serious reservoir damage if there is a cross flow phenomena. Therefore, temperatures measurement at varies depths were used to establish the temperature profile which is reflecting the downhole condition. Several oil wells are subject to be evaluated through the campaigns in terms of downhole integrity especially casing leaks problems. Due to long period of shutdown for the field, close monitoring surveys with more focus on the aged wells are required to avoid flow behind pipe and cross flow phenomena, which will lead to the formation damage and production losses.

The applied approach which is related to Well Integrity Management (WIM) started by creating a baseline in terms of temperatures profile for each well at cost effective time-lapse. The reference is a geothermal gradient log recorded in shut-in condition. Slickline operations were performed to execute the bottomhole temperature surveys. The temperature profile interpretation added great value in terms of confirming the wellbore integrity and detecting anomalies such as a sustained casing pressure and casing leaks. Effectiveness Well Integrity Management (WIM) included the methodology of monitoring, detecting, and localizing leaks phenomena across shallow aquifers was used to extend the well operability life.

The approach was implemented on several field cases in order to detect casing leaks in offshore oil wells. A capture of temperature anomalies were found with a clear deviation from the baseline gradient. Based on the evaluation results, many of anomalies were related to the entry of fluids into the borehole. However, there were some cases indicated that the fluid flow was upward. It is noted that the temperature was affected by the type of occupied fluid into the outside casing and by the type of movements. As a result, the temperature profile was sensitive to not only the borehole condition but also the formation type and the casing-formation annulus.

The paper covered field wells completions evaluated and interpreted their temperature profiles to capture the temperatures anomalies leading to casing leak, flow behind pipe, and a cross flow phenomena. The approach applied further investigation by integrating technique with other integrity surveillance logs. In addition, the results from the workover operation with the remedial actions shared in order to validate the findings.
Combining Two- and Three-Phase Coreflooding Experiments for Reservoir Simulation Under WAG Practices
Authors: Moghadasi Leili , Ranaee Ehsan , Renna Dario , Bartosek Martin , Maddinelli Giuseppe , Masserano Franco , Cominelli Alberto , Inzoli Fabio , Guadagnini Alberto
Published: January 2020

Enhanced oil recovery (EOR) processes may often involve simultaneous flow of two or three immiscible fluids inside the reservoir. A precise evaluation of relative permeabilities is critical to quantify multi-phase flow dynamics, assisting improved management and development of oil- and gas- bearing formations. This study illustrates the results of laboratory-scale investigations of multiphase flow on a sandstone reservoir core sample to evaluate relative permeabilities under two- and three-phase (i.e., water, oil, and gas) conditions. We use the ensuing information to simulate WAG injection at reservoir scale.

The experiments are conducted at high temperature, consistent with reservoir conditions, to obtain two- (oil/water and oil/gas) and three-phase (oil/water/gas) relative permeabilities through Steady-State (SS) technique. Our laboratory workflow allows for an improved investigation by combining coreflooding experiments with in-situ X-Ray evaluation of local saturation distribution. The latter technique permits to asses slice-averaged phase saturation along the rock core, enabling to compute saturation profiles and average saturations while flooding, thus yielding significant advantages over traditional methodologies based on mass balance.

Three-phase steady state (SS) experiments are performed by following diverse saturation paths, and the complete experimental dataset is provided to (a) assess the occurrence of local three-phase saturation conditions and (b) possibly investigate hysteretic effects of relative permeabilities. We evaluate three-phase relative permeabilities across the entire three-phase saturation region by leveraging a Sigmoid-based model (Ranaee et al., 2015).

The resulting set of experimental two- and three-phase coreflooding results constitute a unique dataset which is then employed for reservoir simulation studies mimicking WAG injection and results are discussed in comparison with reservoir production under a waterflooding scenario.
Using the Product-Process Matrix to Identify Repeatability in Capital Project Activities to Improve Project Execution Efficiency
Authors: Shenoy Ramachandra
Published: January 2020

Project teams in oil & gas major capital projects usually believe that large oil & gas capital projects typically have unique scope and are comprised of highly customized elements. We show that large capital oil & gas projects have a lot of inherent repeatability, using a well-known analysis from Operations Science of processes and products called the Product-Process Matrix. We use this observation to show Operations Science methods, specifically a technical framework known as Project Production Management (PPM), can be applied to the execution and delivery of all projects, large or small, customized or standardized, improving project performance over prior conventional project management practices.

We elaborate upon the Operations Science foundation underpinning the PPM framework, showing how it allows for a scientific analysis of the repeatability occurring in project work activities in different forms – knowledge, process and products. We start by identifying the assumptions of repeatable knowledge implicit in the disciplines used in conventional project management. We review the prior literature and taxonomy of a production system. All manufacturing systems are production systems. However, not all production systems are manufacturing systems. Manufacturing systems are but one type of production system. We explain that the belief that PPM is a simple application of line flow – also known as high volume manufacturing – is an overly simplistic characterization of PPM. A deeper analysis of the work activities of projects shows different types of production systems embedded within a typical project. Describing the work activities encountered in a project as a set of inter-connected production systems makes them amenable to the modeling and analysis tools of PPM, such as Little's Law and Kingman's Formula, which can be used to predict the limits of project execution and where best to manage variability by the strategic allocation of buffers such as capacity, inventory and time. We illustrate the concepts by identifying examples of repeatability present in an actual oil & gas capital projects.
A New Tool for Searching Sweet Spots by Using Gradient Boosting Decision Trees and Generative Adversarial Networks
Authors: Tang Jizhou , Fan Bo , Xu Ganchuan , Xiao Lizhi , Tian Shouceng , Luo Shaocheng , Weitz David
Published: January 2020

High-density completions prevail in shale oil formation in China due to the difficulty of identifying the sweet spot with high accuracy. Knowing the location of sweet spots benefits the horizontal well drilling and the selection of perforation clusters. Generally, field engineers determine sweet spots from the well logging interpretation. However, a group of prevalent classifiers based on gradient boosting decision trees were introduced to automatically determine sweet spots according to datasets from the well logging. Based on boosted tree algorithms, Extreme Gradient Boosting (XGBoost), Unbiased boosting with categorical features (CatBoost) and Light Gradient Boosting Machine (LightGBM) are utilized to control the over-fitting issues. Compared with linear support vector machines (SVMs) or kernel machine, these robust algorithms can deal with comparative scales of the features and learn non-linear decision boundaries via boosting. Moreover, they are less influenced by the presence of outliers. Another prevailing approach, named Generative Adversarial Networks (GANs), was implemented to augment the training dataset by using a small number of training samples. In terms of the training purpose, we randomly selected 60 horizontal wells. In each well, tens to hundreds of datasets of different formation intervals were collected. Features, such as resistivity, interval transit time, layer thickness, shale content, porosity, permeability, oil saturation, and coordinates in three dimensions, were extracted from well-logging datasets and regarded as inputs for classifiers. Datasets of remaining wells were used for testing. Compared with conventional SVMs, the prediction accuracies of sweet spots by XGBoost and CatBoost were significantly improved to 81.61% and 82.5%, respectively. Additionally, GANs, as an unsupervised machine learning tool, have been attempted to augment the dataset by utilizing a relatively small number of training samples. A generative model is used for capturing the data distribution, and a discriminative model aims at predicting a label to which that data created by the generative model. Without special pre-processing of the input datasets and fine tuning CTGANs model, the fake dataset could still bring 68.58% accuracy for all detections and 59.01% of the label corresponding with oil formation that showing its potential in data augmentation. This paper illustrates a new tool for categorizing the reservoir quality by using gradient boosting decision trees and GANs methods, which further helps search and identify sweet spots. An extensive application has been built for the field cases in a certain oilfield. This tool provides a guideline for covering more sweet spots during the drilling and completion treatment, which immensely decreases the exploration cost.
New Approach to History Matching of Simulation Models with Discrete Fracture Networks
Authors: Maucec Marko , Zhang Shu , Meza Camargo Otto , Olukoko Olugbenga
Published: January 2020

Simulations of fractured reservoirs are usually performed by dual porosity, dual permeability models. Traditional deterministic workflows that model prominent fracture lineaments often fail to integrate quantification of uncertainty, inherent in fracture spatial distribution and properties. This poses significant challenges on history matching and frequently requires extensive manual beyond geological consistency to achieve the match. We present a method for assisted history matching (AHM) that calibrates models of fractured reservoirs by dynamically updating matrix properties and discrete fracture networks (DFN), while retaining the highest levels of geological consistency and model predictability. The new workflow simultaneously interfaces between applications for building the geo-model and the DFN model "on the fly" and integrates them into a Closed-Loop framework for global stochastic optimization using evolutionary algorithms. Rigorous uncertainty quantification is performed with sensitivity analysis and variability refinement, using the multi-level design of experiments (DoE). We deploy the workflow on the model of a fractured and faulted reservoir developed under natural aquifer drive. Geo-modeling uncertainty workflow generates multiple realizations of seismic-inverted acoustic impedance, used as a 3D trend for populating porosity, with varying variogram parameters. Uncertainty in porosity-permeability correlation coefficients is leveraged to generate multiple, spatially diverse permeability models. Realizations of porosity and permeability are used to generate corresponding realizations of water saturation. By sampling probability distributions of fracture density, geometry, aperture and orientation, 3D realizations of fracture porosity, fracture horizontal and vertical permeability and matrix-fracture transfer parameters are generated. The workflow produces statistically and geologically diverse ensemble of matrix and DFN model realizations that results in excellent variability in dynamic simulation response and confines the observed data. The multi-objective misfit function (OF), subject to minimization in the AHM process, incorporates static well pressures and was evaluated with a reservoir simulator that employs Massive Parallel Processing to achieve practical computation times, even with large-scale simulation grids. The presented AHM workflow demonstrates a unique functionality that enables the integration of DFN geo-mechanical properties (e.g. paleo-stress, pore-pressure) as predictors for fracture network attributes in the process of Closed-Loop model inversion and optimization. The method enables a robust, multivariate reservoir uncertainty quantification and dynamic calibration and delivers geologically consistent fractured reservoir models for reservoir forecasting under uncertainty.
Wireless Activated Drilling Microchip for Wellbore Temperature Measurement
Authors: Shi Zhaorui , Li Bodong , Gooneratne Chinthaka , Zhan Guodong David
Published: January 2020

Small-sized drilling microchips become useful and efficient logging devices for distributed downhole temperature and pressure measurement. In this paper, new generation of temperature and pressure microchips are developed. Advanced technologies including micro-size wireless charging and light weight protective material have been used to improve reliability and durability as well as the recovery rate of the microchips. Tests have been conducted both in the laboratory and in the field for evaluation.

During drilling operations, initialized microchips are dropped into the drill pipe while making pipe connections. The microchips travel downwards in the drill pipe and pass through the bit nozzle carried by the mudflow. Then microchips are pushed upwards in the annular section and are eventually recovered at the shale shaker. Distributed downhole parameters such as temperature and pressure measurements are recorded periodically in the memory of the microchip, which can be downloaded entirely after the recovery process.

The lab test result shows the new generation microchip is able to work longer in lower power consumption under simulated extremely harsh conditions. By applying different light weight protective material, microchip can adjust its own density close to the mud density to make it easier for flowing upward in the annular section. This way the microchip recovery rate can be increased in the field. The field test results show an excellent correlation between the measurements and the pump flow rate. The wellbore in-situ temperature profile processed from the microchips could be of significant importance for optimizing cement formulation.

Unlike other downhole measurement method, microchips provide valuable pressure and temperature data in front of the drill bit while drilling. It is an efficient diagnostic tool for identifying problems encountered in drilling process, such as seepage, lost circulation and local overheating. Microchip technology can be considered as an open distributing sensing platform for integrating other sensor units and creating downhole sensor networks, which will be a digital evolution to achieve internet of things (IoT) in oil and gas industry.
Improving the Reliability for Remote Functioned Barrier Valves. A Truly Multicycle, Remote Activated Barrier Valve
Authors: Croucamp Leandre , Munro Christopher , Murdoch Euan
Published: January 2020

The reliability of subsurface barrier valves has long been an industry problem. This can lead to costly interventions, especially in deepwater subsea markets. This paper describes the world's first deployment of multicycle barrier valves in 2 subsea wells in Australia. These valves use innovative methods of both remote activation and triggering, previously unavailable on the market, to attain a step-change in reliability.

The remote activated barrier valves were deployed as part of a subsea gravel pack system. They were initially run in hole (RIH) in the open position as part of the lower completion, then closed mechanically. The valve was subsequently opened via radio frequency identification (RFID) tags and then closed again mechanically, to allow running of the upper completion. Frequency modulated pressure cycles were applied to the well to open the valve and enable the well to flow.

The valve functioned exactly as planned, and it demonstrated that it could be closed multiple times on a semi-sub vessel. The valve was then opened via RFID tags conveyed on wash pipe. This is a much more reliable method when in high-debris environments. The valve was opened for the final time via frequency modulated pressure cycles. These pressure cycles are better able to be transmitted through debris and are not affected by other hydraulic events in the well.

The hydraulic pump that actuates the tool provides a constant force directly to the ball valve mechanism and is not subject to failures over time, unlike existing gas charges, ratchet mechanisms or springs. The RFID, mechanical or pressure cycles that trigger the valve offer a huge increase in operational flexibility that have never been able to be realized with existing technologies.
New and Advanced PDC Bit Design with Innovative Backup Layout Cutters Helps Extend Bit Life without Sacrificing Rate of Penetration During a Heterogeneous Application, Northwest Kuwait
Authors: Boussahaba Hocine , Sugumar Jayaram , Vrnak Kyle , Benyoucef Lyes , Fadtare Ashish , Al-Shammari Altaf , Al-Failakawi Khaled , Dutta Abhjeet , Al-Khaldy Meshal
Published: January 2020

The 9 1/4-in. polycrystalline diamond compact (PDC) bit is a unique size necessary for long-interval deep-drilling casing programs in Kuwait. Drilling the section is a major challenge because the long interval consists of nonuniform lithology with variations in compressive strengths, and it contains an abrasive ultra-hard sandstone, a compact hard shale with a low rate of penetration (ROP) performance, and carbonates with shale, oolite, and sand traces. The interval is commonly drilled using either two or three new PDC bits, and extra trips are expected.

Efforts were made to substitute the numerous PDC bit runs with one customized and reliable design that can overcome formation hardness and variations in compressive strength and maintain the same ROP to total depth (TD) with limited success, even though the idea of backup cutters has existed for decades. A new, durable PDC design was implemented with the objective of helping improve the ROPs across all intervals. The innovative backup cutter placement design and minimal critical depth of cut for each primary and backup cutter in the same radial position are the most desirable solutions.

The new and innovative PDC cutters’ distribution structure using the new bit design software coupled with an innovative backup cutter placement minimized the calculated bit wear and maintained the cutters’ sharpness along the entire section without needing an extra trip or a new second bit, which produced the best performance achieved in the northwestern Kuwait fields.

The new bit design achieved the longest footage drilled in Kuwait for a single bit of 9 1/4-in. size with a competitive ROP compared to previous cases. The used bit came out of the well in excellent condition with minimal normal wear.

A case study of an innovative PDC cutting structure layout using the new PDC bit design with efficient backup cutter placement, bit formation interaction modeled to help predict cutting structure wear, and advanced rock mechanics analysis are discussed. The new backup cutters’ layout procedure extended bit life without sacrificing ROP.
Understanding the Limit of Wellbore Cleanliness During Connection Via Theoretical Study and Field Implementation
Authors: Ruzhnikov Alexey
Published: January 2020

One of the most common operations while drilling is the connection of drill pipes after every stand drilled. The main concern prior and during this operation is to ensure that annulus around the bottom hole assembly (BHA) and drill string is clean of any cuttings, when often excessive time spent to achieve it. This manuscript discusses modeling, field implementation and operational observations of changing the standard practices, what led to significant time reduction while drilling vertical, deviated and extended reach (ERD) wells.

The most common worldwide practice is to wash / ream a stand up and down prior to connection to remove any potential cuttings around BHA. Having this in mind the objective was set to minimize this time as much as possible towards full elimination. To accurately predict the cuttings lifting forces, annulus cleanliness, hook load fluctuations advanced modeling combining torque, drag and hydraulics was developed. The model considers all the key parameters such as drilling fluid density and rheology, BHA configuration, pumping rates, wellbore geometry, temperature and pressure effects, etc. and can estimate the time required to spend at the end of every stand.

A total of up to one hundred jobs were simulated and followed by the field implementation in the different sections, which were ranged by bit size (from 17-in. to 6-in.), inclination and complexity (from zero to 90 degrees, including ERD wells) as well as other affecting parameters such as losses, wellbore stability etc. The data from the initial wells were crosschecked vs available MWD/LWD data (as equivalent circulating density, annulus pressure while drilling, temperature etc.) to confirm the results of the simulations.

As a result, new connection practices were developed with minimum clean out time prior to a connection. Two examples: in the vertical wells the pre-connection time was reduced almost to zero and only two minutes drill-off now done; in deviated wells including ERD a standard approach of washing up / reaming-down a stand was replaced to 2 - 3 minutes drill-off followed by ream up and down of 10 ft only. Together with other changes it not only allowed the decrease a connection time by up to 60% without the negative incidents like stuck pipe, but also minimized impact on the bottom hole assembly (BHA) components happening due to off bottom stick / slip. This resulted in great time savings, where around 2 days can be saved for 20,000 ft wells vs previously applied practices.

The manuscript describes an engineering-based approach to connection practices which allows to shorten well construction time and decrease the well cost without additional risk.
Non-Productive Time Reduction In Overpressured Reservoirs Through Seamless Integration of MPD, LWD And RSS Technologies.
Authors: Amorocho Claudia , Galindo Jhonny , Hernandez Julian , Stich Chad , Valecillos Juan , Oliver John , Scherer Gary
Published: January 2020

This case study shows a cooperative implementation of managed pressure drilling (MPD), logging while drilling (LWD) and rotary steerable system (RSS) technologies to prevent non-productive time (NPT) while drilling through a section with a tight pressure window in a highly over-pressured reservoir in the US. Drilling risks were proactively reduced by providing real time data transmission for reservoir characterization and identification of critical well sections.

The bottom hole assembly (BHA) was designed to be able to provide high quality measurements according with specific priorities in real time formation characterization and post mortem evaluation. The data transmission was also optimized to be able to monitor the performance of the rotary steerable system (RSS) as well as provide logging measurements that allowed decision making in real time. The implementation of MPD and the continuous monitoring of pressure while drilling (PWD) data allowed to adjust the downhole pressure profile to minimize the impact of drilling hazards by early detecting micro influxes and micro losses reducing considerably their size and impact to control them.

Acquisition and transmission of high-quality logging while drilling data in real time allowed to identify the formations being drilled using Gamma Ray and resistivity logs anticipating the risk associated with each formation. The accurate identification of the pore pressure ramp, a consequence of using real-time MWD GR logging to correlate incoming formation tops with offset data, and the monitoring of the PWD data help to proactively respond to the imminent drilling hazards allowed to drill through these problematic sections using an underbalanced mud weight with the help of MPD which can adjust the pressure profile immediately reducing the risk of NPT. In addition to LWD and MPD technologies, the implementation and monitoring of RSS reduced the risk of downhole mechanical problems. Furthermore, acquired high-resolution sonic and density data from memory provided means to tie together the seismic data, in time, and LWD data, in depth, in order to make accurate predictions of incoming formations tops for future wells. This improved predictive capability to identify the depth range of the pore pressure ramp, while the correlative in-formation log signatures provided robust analysis of offset producing trends.

Drilling scenarios that otherwise deemed unattainable due to the big potential for drilling hazards, can currently be tackled safely while also optimizing capital expenditure through the implementation and monitoring of reliable LWD, MPD and RSS systems. The designed BHA allowed reliable data acquisition and the use of MPD enabled the versatility of instantaneously adjusting the downhole pressure profile leading to a flawless drilling operation with reduced NPT associated to pressure-related issues.
Saudi Aramco Drives Technological Initiatives for Groundwater Conservation In Oil & Gas Production Facilities
Authors: Ahmed Syed A. , Koleshwar Vilas S. , Yousef Khaled K. , Albluwi Saif F. , Owaidhi Sultan H.
Published: January 2020

This paper describes Saudi Aramco's efforts in conserving groundwater in Kingdom of Saudi Arabia. Driving corporate-wide water conservation initiatives, Saudi Aramco has identified several technologies to pilot test and deploy. One of these initiatives involves the unique idea of treating relatively low salinity produced water, from crude oil desalters at Gas Oil Separation Plants, for use as a wash water stream for crude oil desalting. The concept, known as Desalter Effluent Reuse Technology (DERT), was successfully field-tested and is now being deployed on a commercial scale.

The idea of treating & reusing desalter effluent water as desalter wash water and thereby conserving groundwater, was submitted for US patent on September 29, 2017, and assigned a Serial No. 15/719,884 by the US Patent and Trademark office. Saudi Aramco prepared a roadmap to pilot test several Desalter Effluent and produced water-based water conservation technologies, to deploy at GOSPs where seawater is not economically accessible.