bluuebunny/crossref_metadata_2025 huggingface dataset:
Automatic Simulation Data Update: A New Innovative Way to Expedite Historical Data Extension for Models
Authors: Tayeb Yousef , Naseef Faisal , Ghamdi Amell
Published: March 2021

Historical data in reservoir simulation models becomes outdated with time and the gap between the latest history matched model and the current situation increases. Time is essential, especially with escalated numbers of simulation models. Therefore, updating models in a frequent manner requires a new approach to maximize human resources and deliver timely answers. Engineers must also ensure that the existing quality checked input is secured and that data integrity is maintained during updates.

In the conventional method of updating simulation model data, engineers go through several steps to acquire new data from corporate databases and fill the extended missing periods. This procedure involves interacting with many applications, which is very time-consuming. To expedite this process, a new methodology is applied that automates each of the single interactions together in a one-step procedure. A smart in-house tool connected to the corporate database extracts all necessary data and generates consistent inputs, including rates, pressures and well completions as data is developed. The tool then incorporates the new data into the existing simulation model's data input.

The smart automation tool shows the positive impact of the one-step methodology in the updating process. As an example, the new tool was tested on a mega-field, where a vast number of wells were perfectly updated and extended to the current simulation date. The updating time was drastically reduced using the indroduced process and engineers were able to keep their existing files. In addition, the smart automation tool was able to connect to the corresponding geological model seamlessly to generate the specified perforation data after incorporating all trajectory and completion data automatically.

This paper illustrates that the automation of the updating process is essential to increasing workflow efficiency. The opportunity for fast and frequent simulation model updates leads to a better understanding of reservoir behavior and improves forecasting.
Advanced Completion Optimization ACO: A Comprehensive Workflow for Flow Control Devices
Authors: Ahmed Elfeel Mohamed , Goh Gordon , Biniwale Shripad
Published: March 2021

There is a growing interest in downhole flow control devices (FCD) as they can be used to counter the effects of reservoir heterogeneity and improve hydrocarbon recovery. The variety of FCD types, sizes, and specifications makes it challenging to select the right device, providing an optimal investment return. Reservoir engineers play an essential role in identifying and evaluating the possible options based on numerical simulation models. This paper utilizes a transient numerical optimizer, designed for FCD with active controls, as a generic tool for lower completion optimization, including passive and autonomous FCD.

The workflow consists of five steps. The first step is to determine a practical number of completion zones in a well, given the reservoir heterogeneity and completion string considerations. The second step is to explore the potential gains of downhole control without accounting for device-specific limitations. Here, we integrate a local optimization method to run several simulations with reactive and proactive strategies. In the third step, we contrast the local optimization simulations results to determine the suitable family of FCD: passive, autonomous or active. In step four, we ensure the selected FCD family is correctly modelled in reservoir simulation, particularly for autonomous devices, based on a recently published method to calculate equipment specific flow coefficients. Finally, optimization runs are performed using the selected FCD family and specific coefficients.

The workflow is demonstrated on a synthetic carbonate sector model with a ~2,000 m horizontal well. It can be shown that analyses of the local optimization results provide quick guidelines to screen and select suitable lower completion equipment for the well and reservoir. Furthermore, the local optimization results can be used to design the selected lower completion string. The suggested workflow is the first of its kind in that it caters to all FCD families. The workflow uses an efficient local optimization method in a next-generation reservoir simulator. The efficiency gains from using the optimizer allows the decision-making time required for FCD evaluation to be an order of magnitude less than the logging and completion operation timeframe. Hence, the workflow enables efficient real-time design, planning and optimization of FCD.
The Model of Sandbody Controlled by Dynamic Provenance System and its Exploration Significance in Superposition Area of Strike-Slip and Extension Stress in the South of Bohai Sea
Authors: Zhen Huang , Bo Yang , Guoying Li , Jian Ren , Xiaoling Wang
Published: March 2021

Laizhouwan sag in Bohai Bay basin is a fault basin controlled by extensional fault depression and strike slip pull apart, which is an important oil and gas exploration area in Bohai Bay. Exploration practice shows that the prediction of high quality reservoir is the core problem of exploration in this area. Based on the analysis of drilling, seismic data and structural physical simulation in Laizhouwan depression, this paper analyzes the structural deformation under the stress field of strike slip extensional superposition, and points out the dynamic source controlled sand model in the strike slip extensional superposition area. Firstly, The structural response of "pressure relief settlement, pressure boosting uplift" under the mechanism of strike slip extension stress superposition stress is the root cause of block uplift drop alternation transformation. As a result, the southern slope zone of Laizhouwan depression shows the structural pattern of early uplift and late uplift in the East and early uplift and late uplift in the west, forming a "seesaw" structural evolution pattern. Secondly, the unique paleogeomorphology controls the orderly distribution of sedimentary system in time and space. In the Paleocene, the east uplifted, forming a local provenance system. In the denudation area above the slope break developed fracture weathering shell type reservoirs, and the subsidence area under the slope break developed fan delta deposits; In the early Eocene, the relatively flat platform palaeogeomorphology was developed, which created favorable conditions for the development of mixed sedimentary body of lacustrine carbonate and delta; At the end of Eocene, the West was pressurized and uplifted, the East was released and subsided, and the braided river delta sediments of Western provenance were developed. Under the guidance of this recognition, the hidden dynamic provenance was successfully identified in the study area.
Case Studies for the Successful Deployment of Wells Augmented Stuck Pipe Indicator in Wells Real Time Centre
Authors: Meor Hashim Meor M. , Yusoff M. Hazwan , Arriffin M. Faris , Mohamad Azlan , Tengku Bidin Tengku Ezharuddin , Gomes Dalila
Published: March 2021

The restriction or inability of the drill string to reciprocate or rotate while in the borehole is commonly known as a stuck pipe. This event is typically accompanied by constraints in drilling fluid flow, except for differential sticking. The stuck pipe can manifest based on three different mechanisms, i.e. pack-off, differential sticking, and wellbore geometry. Despite its infrequent occurrence, non-productive time (NPT) events have a massive cost impact. Nevertheless, stuck pipe incidents can be evaded with proper identification of its unique symptoms which allows an early intervention and remediation action. Over the decades, multiple analytical studies have been attempted to predict stuck pipe occurrences. The latest venture into this drilling operational challenge now utilizes Machine Learning (ML) algorithms in forecasting stuck pipe risk. An ML solution namely, Wells Augmented Stuck Pipe Indicator (WASP), is developed to tackle this specific challenge. The solution leverages on real-time drilling database and supplementary engineering design information to estimate proxy drilling parameters which provide active and impartial pattern recognition of prospective stuck pipe events. The solution is built to assist Wells Real Time Centre (WRTC) personnel in proactively providing a holistic perspective in anticipating potential anomalies and recommending remedial countermeasures before incidents happen. Several case studies are outlined to exhibit the impact of WASP in real-time drilling operation monitoring and intervention where WASP is capable to identify stuck pipe symptoms a few hours earlier and provide warnings for stuck pipe avoidance. The presented case studies were run on various live wells where restrictions are predicted stands ahead of the incidents. Warnings and alarms were generated, allowing further analysis by the personnel to verify and assess the situation before delivering a precautionary procedure to the rig site. The implementation of the WASP will reduce analysis time and provide timely prescriptive action in the proactive real-time drilling operation monitoring and intervention hub, subsequently creating value through cost containment and operational efficiency.
Improving the Directional Behavior of PDC Bits Affected by Stick-Slip: A Statistical Approach
Authors: Reboul Sébastien , Al-Mulaifi Mohammad , Al-Othman Ahmad , Shata Atef , Mohamed Ibrahim , Pelfrene Gilles , El-Genidy Ehab , Gamal Mohamed , Cuillier Bruno , Amran Fatheeni A. , Maïga Abiboulaye
Published: March 2021

Torsional vibrations are a very common phenomenon affecting drilling operations by limiting efficiency, increasing the risk of downhole equipment failure and generating additional costs, particularly when their most severe form is encountered, the stick-slip. It is less known that torsional vibrations also strongly affect directional drilling operations reducing directional stability and tool face control. In this paper, the highly variable solicitation induced by torsional vibrations is addressed with a statistical approach. This approach, used successfully in Kuwait applications, resulted in an operational savings of 30% of the cost per foot over a panel of more than 15 runs analyzed.

Steerability and directional stability is critical on directional wells, especially when using push-the-bit systems with PDC bit due to side force distributed unevenly over one bit revolution. Most of today bit design comparisons are made with an average steerability factor computed over one full revolution of the bit. The method described in this paper is going further in details and looks at the evolution of directional performance indicators within one bit revolution. With the help of a state-of-the-art 3D bit-rock interaction model, which simulates the drilling environment considering the drive system mechanism and both the drill bit and the hole being drilled as a set of 3D meshed surfaces, an accurate picture of the directional stability of the bit design is available. This approach is complemented by a statistical analysis which allows to simulate a multitude of input parameters combinations and to map the directional response of a bit design in a more robust way.

Based on the results of the statistical analysis, an optimized design was selected and manufactured for a 12 ¼’-in. rotary steerable system (RSS) directional application known for having torsional vibration limitations. As revealed by the simulation results, this design was expected to exhibit a better directional stability than previous bit design iterations. This optimized design was run on RSS and positive displacement motor (PDM) assemblies and successfully drilled several wells in different fields of Kuwait operations ground. It experienced smooth and stable directional control while reducing the risk for torsional vibrations and resulted in tremendous reduction of the overall cost per foot.

PDC bit selection and design process have considerably evolved in the last decade with the use of increasingly accurate simulations models. This paper presents the next step of evolution dedicated to delivering the best adapted solution to any given scenario by examining in greater detail the directional response of a drill bit.
Understanding the Effect of Rock Compressibility on CO2 Storage Capacity Estimation in a Depleted Carbonate Gas Reservoir
Authors: Chidambaram Prasanna , Tewari Raj Deo , Mohd Ali Siti Syareena , Tan Chee Phuat
Published: March 2021

Avoiding or reducing greenhouse gases emission in the atmosphere requires extensive application of technologies and one of them is underground CO2 sequestration. Capture and storage of CO2 in depleted hydrocarbon reservoirs can reduce greenhouse gases released into the atmosphere effectively. Hydrocarbon reservoirs are considered one of the ideal geologic storage sites as they have held hydrocarbons over millions of years. Their architecture and properties are well understood due to exploration and production activities from these reservoirs. Storage projects require a large depleted hydrocarbon reservoir with good reservoir properties and are affected by several factors including voidage created by hydrocarbon production, pressure, architecture, formation permeability, aquifer influx, subsidence and compaction, and rock compressibility to name a few. Thus, realistic estimation of the storage capacity of the reservoir is a key step in the evaluation of CO2 storage plan. A good history matched simulation model incorporating the geomechanical parameters is essential to estimate storage capacity of the reservoir.

Three major depleted gas reservoirs in Central Luconia field, located in offshore Sarawak, are being evaluated for future CO2 storage. Reservoir simulation is used as a tool to estimate future CO2 storage capacity of these reservoirs. Reliability of forecast from a reservoir simulation model is dependent on the quality of history match achieved. Hence it is believed that CO2 storage capacity estimates obtained from a good history matched simulation model must be reliable. However, during history matching exercise in these reservoirs, it was observed that an acceptable history match could be achieved with a range of rock compressibility values and aquifer influxes. Generally, a constant value of rock compressibility is used in conventional simulation. For example, in order to obtain an acceptable history match, with a lower compressibility, a larger aquifer influx is needed and vice versa. Interestingly, a forecast using these history match cases yield different CO2 storage capacities. A closer evaluation shows that aquifer influx has a strong impact on future CO2 storage capacity.

An acceptable quality of history match can be obtained for a range of rock compressibility values when aquifer influx is adjusted along with it. Sensitivity analysis shows that future CO2 storage capacity in depleted hydrocarbon reservoir is sensitive to rock compressibility used in the simulation model. A detailed sensitivity analysis along with multiple history match scenarios is necessary to understand the range in future storage capacity when evaluating CO2 storage plan.
Convolutional Neural Networks for the Classification of the Microstructure of Tight Sandstone
Authors: Reyna Flores Ana Gabriela , Fisher Quentin , Lorinczi Piroska
Published: March 2021

Tight gas sandstone reservoirs vary widely in terms of rock type, depositional environment, mineralogy and petrophysical properties. For this reason, estimating their permeability is a challenge when core is not available because it is a property that cannot be measured directly from wire-line logs. The aim of this work is to create an automatic tool for rock microstructure classification as a first step for future permeability prediction.

Permeability can be estimated from porosity measured using wire-line data such as derived from density-neutron tools. However, without additional information this is highly inaccurate because porosity-permeability relationships are controlled by the microstructure of samples and permeability can vary by over five orders of magnitude. Experts can broadly estimate porosity-permeability relationships by analysing the microstructure of rocks using Scanning Electron Microscopy (SEM) or optical microscopy. Such estimates are, however, subjective and require many years of experience. A Machine Learning model for the automation of rock microstructure determination on tight gas sandstones has been built using Convolutional Neural Networks (CNNs) and trained on backscattered images from cuttings.

Current results were obtained by training the model on around 24,000 Back Scattering Electron Microscopy (BSEM) images from 25 different rock samples. The obtained model performance for the current dataset are 97% of average of both validation and test categorical accuracy. Also, loss of 0.09 and 0.089 were obtained for validation and test correspondingly. Such high accuracy and low loss indicate an overall great model performance. Other metrics and debugging techniques such Gradient-weighted Class Activation Mapping (Grad-CAM), Receiver Operator Characteristics (ROC) and Area Under the Curve (AUC) were considered for the model performance evaluation obtaining positive results. Nevertheless, this can be improved by obtaining images from new already available samples and make the model generalizes better. Current results indicate that CNNs are a powerful tool and their application over thin section images is an answer for image analysis and classification problems.

The use of this classifier removes the subjectivity of estimating porosity-permeability relationships from microstructure and can be used by non-experts. The current results also open the possibility of a data driven permeability prediction based on rock microstructure and porosity from well logs.
Application of Geological Modeling Technique Based on Seismic Frequency Division Processing and Fluids Substitution Forward Modeling in Lithologic Gas Reservoir Risk Assessment
Authors: Liu Zongbin , Lv Zuobin , Wen Jiatao , Yan Hao , Yang Zhicheng
Published: March 2021

JZ Gasfield is an offshore sublacustrine fan lithologic gas field located in Bohai Bay Basin, in China, with a buried depth of about 1750m. It is currently in the stage of overall development plan preparation. Two exploration wells have been drilled. They show that the gas field has characteristics of rapid lateral change in reservoir, complex distribution range and connectivity of sand bodies. In addition, the few drilling data, large well spacing and low resolution of seismic data in the evaluation stage make it extremely challenging to establish an accurate geological model of gas reservoir.

In order to solve the above problems, in this paper, an integrated geological modeling method based on seismic frequency division processing and fluid substitution forward modeling is proposed. There are four key aspects to this method. (1) Using seismic sedimentology, the lateral distribution ranges of sublacustrine fan sand bodies are described by seismic frequency division processing and interpretation technique and seismic variance attribute. (2) Based on markers of single-well, logging and seismic faceis, the average instantaneous frequency attribute is selected by optimizing the seismic attributes in the dominant frequency band, and then the distribution ranges of three subfacies including inner fan, middle fan and outer fan of the sublacustrine fan are characterized, and the fine sedimentary pattern of the sublacustrine fan is established. (3) Based on an understanding of the sedimentary pattern, fluid substitution forward modeling is carried out, and the superposition and connectivity of the sublacustrine fan sand body are described. (4) A 3D geological model of the sublacustrine fan sand body is established by using a new four-step modeling method including the concept of facies-in-facies modeling: 1) A model of the distribution of the sand body is established through a deterministic modeling method; 2) Within the sand body, according to the division results of subfacies, the distribution model of sub-facies is established; 3) A fine lithofacies model is established by combining stochastic simulation with deterministic modeling and hierarchical modeling from rough to fine under the constraint of a seismic attribute; 4) Petrophysical models are established by lithofacies control, which provide a more accurate geological model for preparation of the gas field development plan.

Based on this comprehensive study, it is concluded that there is a great possibility of reservoir disconnection between the inner fan and the middle fan, where the gas reservoir is located, and the inner fan in the updip position of the structure has the risk of no gas accumulation, and the drilling risk in the development stage is greater than the potential. Based on this geological understanding, the available reserves of the gas field are reduced by nearly 40%.
Achieving Improved Drilling Performance with Hole Cleaning Technology in Horizontal Shale Gas Wells in Sichuan Basin of China
Authors: Ji Guodong , Wang Haige , Huang Hongchun , Cui Meng , Yulong Feixue , Ma Ying , Sun Xiaofeng
Published: March 2021

The horizontal section length of shale gas horizontal wells in Sichuan Basin in the south-west of China generally exceeds 2000m. Cuttings are apt to accumulate and form cuttings beds along such long and curve horizontal sections due to low cuttings carrying capacity, which often results in excessive torque and drag or even stuck pipes during drilling process. According to the statistics dada inthe period of Jan. - Oct. 2019, more than 25 stuck pipe incidents and 15 rotary steering tools loss in borehole were reported due to inefficient cuttings transportation in the long horizontal wells in Sichuan Basin.

This paper studies the cuttings transportation and cuttings bed formation in horizontal wells. A prediction model for the distribution of cuttings bed was established. A monitoring and analysis software for the cuttings bed and cuttings cleaner with V-shaped spiral blades that is used to agitate the cuttings bed wasdeveloped. The software calculates the distribution and thickness of the cuttings bed according to the well trajectory, wellbore structure, drilling fluid characteristics, etc., and provides the optimal operating parameters for the removal of the cuttings bed by the rotating and reciprocating drill string. Then, the drill cuttings remover in the drill string moves to the predicted position of the drill cuttings, scrapes the drill cuttings and creates a swirling flow during the pipe rotation. The combined application of software and makeup remover can effectively solve the issue of borehole cleaning in long horizontal wells.

One of the field applications was carried out in the well Ning 209H12, a shale gas horizontal well in Sichuan Basin. The well experienced excessive torque and drag issue during the tripping of drill string of long horizontal section. Thesoftware ran based on oil well data, and it determines the placement and thickness of cuttings beds in the well and calculates the optimal operating parameters for a flow rate of about 32L/s and a speed of 100rpm to remove them. By rotatingand reciprocating the drill string with recommended operating parameters along the cuttings bed interval, the removers helped cleaning the cuttings bed efficiently and significant amount of cuttings was observed at vibration screen. After cleaning the cuttings bed interval, the trip smoothly ran to the bottom without any excessive torque and drag, and then continues to drill in cooperation with the removers to the total depth. During the well completion, there was no problem with the operation of electrical logging and production casing.

This cuttings removal technology has been used in other shale gas formations and tight gas formations where horizontal wells are widely used.
Pre-Stack Depth Migration of High Resolution Distributed Acoustic Sensing VSP
Authors: Rusmanugroho Herurisa , Jaya Makky Sandra , Zahir M Hafizal , Rahim M Faizal
Published: March 2021

The performance of pre-stack depth migration (PSDM) on the fiber optic, distributed acoustic sensing (DAS), vertical seismic profile (VSP) data has rarely been reported. We show the results of PSDM for the fiber optic cables, newly developed and tested at a field in Canada. We apply Kirchhoff migration, Fresnel volume migration and reverse time migration (RTM) to the walkway VSP data to obtain high resolution images of the shallow to deeper structures and provide the performance analysis of the migration methods for the DAS VSP data.
Distribution of Volcanic Rocks Porosity of Dissected Kromong Paleovolcano: Analogue of Volcanic Reservoir
Authors: Hadiyanto Imam Fikri , Hanifah Dina , Hamzah Wildan Nur
Published: March 2021

The potentiality of unconventional play on the volcanic reservoir was evaluated for the purpose to deliver an integrated evaluation of shallow reservoir target associated with the Northwest Java Basin (NWJB). This study provides basis discovery for further exploration and dissemination of volcanic reservoir by presenting an overview of geometric and porosity type analysis of Kromong paleo-volcano complex deposits associated with the NWJB comprehensively. Furthermore, reservoir lithofacies and pore space deployment of Kromong volcanic deposits were studied. The detailed lithofacies analysis was carried out based on field observations from several dissected- and obscure dipping-outcrops in Kromong area associated with NWJB. Following this, a set of outcrop samples were processed for megascopic description integrated with thin-section analysis by using the polarized light microscope and XRF, respectively to assess different types of reservoir pore spaces and structure. Subsequently, the physical properties-porosity measurement was conducted using ImageJ software tools to understand the potentiality of high-quality reservoir formation. The results of this study show that rocks in Kromong area associated with NWJB can be comprehensively classified into reefal limestone for carbonate deposit and into 4 categories, including volcaniclastic lava, sheeting joint lava, pyroclastic breccia, volcanic intrusion, for volcanic deposits. The proposed volcanic reservoirs of volcanic play in this study are lithologically composed of autobreccia lava, sheeting joint lava, pyroclastic breccia to andesitic- and andescitic-dikes, which comprises explosive facies and intrusive facies. Pyroclastic breccia reservoirs are primary pore-type reservoirs with devitrified micropores as main reservoir space. Whilst volcanic dikes reservoirs are mainly porous-fractured-type reservoirs with cooling fracture porosity. In conclusion, following factors that control the presence of a volcanic reservoir are lithology, lithofacies, tectonism and vulcanism. Despite worldwide discoveries of volcanic reservoirs, neither the detailed potentiality evaluation nor the postulated assumption of volcanic reservoir development in NWJB field has been examined sufficiently. This contribution offers knowledge benefits by discussing the potentiality of the Cenozoic-Quarternary volcanic reservoir of the NWJB field and providing a reference for future exploration in the petroleum industry.
Fault Detection by Using Instance Segmentation
Authors: Zhu Donglin , Li Lei , Guo Rui , Zhan Shifan
Published: March 2021

Fault detection is an important, but time-consuming task in seismic data interpretation. Traditionally, seismic attributes, such as coherency (Marfurt et al., 1998) and curvature (Al-Dossary et al., 2006) are used to detect faults. Recently, machine learning methods, such as convolution neural networks (CNNs) are used to detect faults, by applying various semantic segmentation algorithms to the seismic data (Wu et al., 2019). The most used algorithm is U-Net (Ronneberger et al., 2015), which can accurately and efficiently provide probability maps of faults.

However, probabilities of faults generated by semantic segmentation algorithms are not sufficient for direct recognition of fault types and reconstruction of fault surfaces. To address this problem, we propose, for the first time, a workflow to use instance segmentation algorithm to detect different fault lines. Specifically, a modified CNN (LaneNet; Neven et al., 2018) is trained using automatically generated synthetic seismic images and corresponding labels. We then test the trained CNN using both synthetic and field collected seismic data. Results indicate that the proposed workflow is accurate and effective at detecting faults.
See the Unseen through Target-Oriented Dip-Steered Seismic Resolution
Authors: Sajid Muhammad , Ghazali Ahmad Riza
Published: March 2021

Seismic resolution plays an important role not only in interpretation and reservoir characterization but also in seismic inversion and seismic attributes analysis. The resolution depends on several factors, including seismic frequency bandwidth, dominant frequency, and layer velocity. This paper presents a spectral resolution enhancement approach that is based on Non-stationary Differential Resolution (NSDR) that honors the local structural dip, better preserves amplitude and improves target-oriented seismic interpretation. The proposed technology is applied to both 2D and 3D seismic volumes and findings are compared with the oil industry common spectral enhancement algorithms. We demonstrate the target-oriented dip steering spectral enhancement method on two 3D field datasets and compare the resulting outcome with those obtained by conventional techniques. It is found that thinly layered subsurface geological features with steeply dipping beds are better defined, with artifacts from the conflicting dips removed.
Parameter Optimization and Application Evaluation of Rotary Percussion Drilling
Authors: Li Bodong , Tu Yulin , Zhan Guodong David , Aljohar Abdulwahab , Sehsah Ossama , Ke Ke
Published: March 2021

Rotary percussion drilling has gained increasing interest in the oil and gas industries because of its high drilling efficiency and good deviation control [1, 2]. In this work, a rotary percussion-based drilling tool is successfully deployed in a test well, and demonstrates a convincing enhancement of the rate of penetration (ROP).

In the test, the rotary percussion tool drilled through a 12 1/4″ hole section with excellent ROP, under a high mud weight (MW) condition of 120 pcf (Pound per cubic feet). The result shows a 22% enhancement on average ROP, and 31% enhancement on instantaneous ROP comparing to the best performing offset well offset well drilled in the same condition.

This paper covers the principle of a rotary percussion-based hammer tool, details in rotary percussion drilling parameters design and bit selection considerations for the effective coupling with the hammer tool. In addition, the paper uses an example of a high MW application to evaluate the overall performance of the tool in ROP enhancement.
Revitalizing Seismic Beyond Geometry Limitations: A Case Study of OBN Survey in Offshore Sabah
Authors: Ngo Lee Sii , Cheah Wai Leng , Sazykin Artem , Menzel-Jones Gavin , Wong Joyce Li , Rong Evonne Yu , B. Muhamad A. Aziz , Supardy M. Iqbal , B. Hashim M. Hakimey , B. Mokhtar M. Afiq , Tee Wei Yong , Shankar Das Prabal , Bt. Bahadon Ima Nazmi , B Harun M. Faeez , Jeevachandran Laletha
Published: March 2021

Ocean-bottom node (OBN) surveys are an increasingly common choice of method for marine seismic acquisition and offer several key advantages. These include recording wide-azimuth data and reliable low-frequency information. Since the start of OBN acquisition almost two decades ago, key challenges remain, not only on equipment handling and data management, but also on the data processing and imaging methodologies as these multicomponent workflows continue to evolve. We present a case study of an OBN survey acquired in offshore Sabah with a cross-spread geometry, in an ultra-shallow-water environment. This study discusses a few key processing challenges encountered due to this sparse acquisition including noise and multiple energy contamination and aliasing on data. We explain the challenges, how these were overcome, and the methodologies we used to enhance the data quality. As the main product for this project is a depth-imaged seismic volume, we also describe the earth model building workflow and imaging tools we used to leverage the advantage of full-azimuth data and multidirectional wavefield recorded in this survey. This includes full-waveform inversion, multi-azimuth tomography, and imaging with multiple.
The Concept of Need for a Downhole Scale Inspection Tool: An Appraisal for an Emerging Technology in Scale Management
Authors: Zoveidavianpoor Mansoor , Rosland Eadie Azahar , Laakkonen Pasi , Aryana Saman , Jaafar Mohd Zaidi , Ibrahim Jamal Mohamad , Kolivand Hoshang , Tewari Raj Deo , Johar Razman Marsoff , Mohamed Zaidi Awang , Salleh Intan Khalida
Published: March 2021

Monitoring techniques in oilfield scale management are expensive, susceptible to error, are not conducted in real-time, and they are non-in situ. Most scale prediction tools (i.e., water analysis and computer-based algorithms) have their deficiency and the need for accurately correlate calculated scaling tendencies with actual field data is evident. Lack of info about type, severity and location of scale deposits can lead to the failure of well intervention jobs. This work aims to serve as an opportunity to provide fertile ground and basis for utilizing new emerging technology for scale management in downhole application.

Research into utilizing sensors along with an advanced computerized imaging procedure in the downhole application has not been explored to the same extent as other applications, such as scale monitoring in pipelines and surface facilities. Downhole Scale Inspection Tool (DSIT) is a new emerging technology which promises to enhance considerably our ability to detect deposits and scale with the aim of sensors and tomography technology. DSIT has enormous potential for application in downhole condition as it uses slickline unit alongside with routine well intervention jobs. The acquired data by DSIT such as temperature, pressure, depth, deposition thickness and permittivity are utilized for downhole scale analysis, monitoring and detection.

When the type of scale is known, it is easier to take the correct steps in preventive maintenance or a cleaning process. Using DSIT, the trend of deposition thickness can be detected and immediately known if it is growing or shrinking. This will help to optimize any chemical feed and also generate substantial savings over time. This paper gives an overview of developing cutting-edge technology in downhole applications for scale management and possible barriers to new technology implementation. Using DSIT can lead to better data acquisition from downhole and contribute to a higher success rate of scale removal in downhole. This technique offers many benefits for scale treatment, monitoring and prediction when filed data is necessary for validation of scaling tendencies.
Research on Intelligent Production Technology of Intermittent Gas Wells in Sulige Gas Field
Authors: Chen Yong , Xie Yonggang , Tian Wei , Wang Xiongxiong , Zhao Zhengyan , Xiao Shuqin
Published: March 2021

An intermittent gas well intelligent production technology is presented that use intelligent methods to determine and optimize the intermittent system of intermittent gas wells and use newly developed remote pressure-controlled well opening equipment that can simulate manual operations and corresponding intelligent control systems. This new approach is based on the research and application of intelligent technology in the production of intermittent gas wells. By establishing the models of gas flow in different types of gas wells, combined with the historical data of typical gas wells, the optimal pen and shut-in well time chart is finally formed. A series of remote pressure-controlled well opening equipment have been developed to replace manual pressure-controlled open well operations at the well site. Through intelligent integration of well site equipment and remote control platforms, an ntermittent gas well intelligent production management system is established. The quantitative determination of the intermittent system of different types of gas wells is realized. The effectiveness of gas well intermittent measures has increased from 72% to 90%. Electromagnetic remote-controlled open well equipment with adaptive decompression and full-open cylinder structure is developed, and can meet the requirements for rapid opening of type Il intermittent gas wells. Needle-valve type remote-controlled open well equipment embedded with intelligent well drilling algorithm is developed, and the fine well opening of class I and Il intermittent gas wells is realized. Hands-free operation is realized, and the workload of operating staff on the well site is reduced by more than 15%. On-site diagnosis of gas well production status, intelligent generation of systems, intelligent analysis and optimization are realized, and intermittent gas wells are transformed from manual management to intelligent management. An intermittent gas well intelligent production management system is established to achieve intelligent management of intermittent gas wells. Complete intermittent gas well intelligent production technology for low ermeability gas fields is described in detail to permit global similar gas field reference. The novelty of the technology lies in the use of intelligent methods to solve the production problems of intermittent gas wells, including reducing the labor intensity ofemployees, improving production efficiency, improving the fine management level of tight gas field gas wells, and reducing the impact of human activities on the natural environment.
Anisotropic Geomechanical Rock Properties Modelling for Unconventional Shale Gas Formation
Authors: Musa Ikhwanul Hafizi , Tan Chee Phuat , Leem Junghun , Altaf Iftikhar , Md Zain Zahidah , Adams Matthew
Published: March 2021

Geomechanical rock properties correlations and modeling approach for conventional reservoirs are inappropriate and unsuitable for unconventional shale gas reservoirs where the shale formation is strong and has very low porosity. These correlations are critical in the development of 1D and 3D geomechanical models which are used for various field applications including drilling optimization, hydraulic fracturing design and operation, and field management. The study investigates various geomechanical rock properties and their relationships to one another using data extracted from rock mechanics testing conducted on shale core samples. For rock elastic properties correlations, dynamic elastic properties determined from compressional sonic velocity, shear sonic velocity and density are plotted against laboratory-measured static elastic properties obtained from triaxial tests. Steps were taken to further refine the properties correlations by separating the data from vertical and horizontal core samples, using data from tests conducted at in-situ confining stress condition, and focusing on data only taken from Field A and nearby fields. Similar steps were also taken to develop the correlations for rock strength properties. Correlations for the shale anisotropic elastic properties were also developed based on ratio of horizontal and vertical elastic properties. Blind tests were conducted on three wells in Field A using the new rock properties correlations which showed good matching of the predicted geomechanical properties with the new correlations and core measured test data.
Prevent Barite Static Sag of Oil-Based Completion Fluid in Ultra-Deep Wells
Authors: Wang Jianhua , Zhang Jiaqi , Yan Lili , Cheng Rongchao , Ni Xiaoxiao , Yang Haijun
Published: March 2021

Oil-based mud (OBM) is the first choice for complex deep wells due to its advantages of high-temperature resistance, good lubrication and borehole stability. But barite sagging under ultra-high temperature during the long-time stationary completion operation may lead to serious problems in ultra-deep wells, for instance, pipe sticking, density variation and well control problems.

In this paper, the influence of high-temperature and high-pressure (HTHP) on the performance of oil-based completion fluid was studied, and a model of rheological parameters was established with HTHP static sag law. The barite sagging stability was evaluated by a high temperature (220°C) and high pressure (100MPa) sag instrument. The results indicated that RM6 value and static shearing force were the main factors of affecting the settlement stability. The viscosity of the completion fluid significantly decreased with the increase of temperature, but increased with the increase of pressure. In addition, the relationship was also studied between HTHP rheology and atmospheric pressure rheology at 50°C. The results showed that when RM6 value was kept above 10, the sag stability factor (SF) of oil-based completion fluid was less than 0.52 at 190°C for 10 days, which proved a good high-temperature sag stability.

Furthermore, the anti-high temperature property of oil-based completion fluid was improved through enhancing the temperature-resistance of the additives. And the high-temperature-resistant organic soil was introduced to raise the RM6 value and the static shearing force. Based on these solutions, the barite sag under high temperature of the oil-based completion fluid was prevented during drilling and completion operation in ultra-high temperature wells.

The oil-based completion fluid was successfully used in Well Keshen 17 (175°C,7475 m) in Kuche piedmont structure and TT 1 well (210°C,6500 m) in Sichuan basin. The casing run smoothly, the oil-test operation was completed smoothly for 15 days, and no barite sag happened. It testified that the oil-based completion fluid had excellent of high-temperature sag stability. Therefore, this oil-based completion fluid is expected to be used widely in ultra-deep wells.
Drilling in the Digital Age: Machine Learning Assisted Bit Selection and Optimization
Authors: Batruny Peter , Zubir Hafiz , Slagel Pete , Yahya Hanif , Zakaria Zahid , Ahmad Alaa
Published: March 2021

Conventionally, a bit is selected from offset well bit run summaries. This method of selection is not always accurate since each bit is run under different conditions which might not be reflected in an offset study analysis.

The large quantities of data generated from real time measurements in offset wells makes machine learning the ideal tool for analysis and comparison. Artificial Neural Network (ANN) is a relatively simple machine learning tool that combines inputs and calculation layers to compute a specified output layer. The ANN is fed over thousands of data points from 17-1/2 in hole sections across multiple wells. A specific model is then trained for every bit with weight on bit (WOB), rotary speed (RPM), bit hydraulics, and lithological properties as inputs and rate of penetration (ROP) as output. The model is finalized when a satisfactory statistical set of KPI's are achieved. Using a combination of Monte-Carlo analysis and sensitivity analysis, different bits are compared by varying parameters for the same bit and varying the bit under the same parameters.

A bit and its optimized parameters are proposed, resulting in an average instantaneous ROP improvement of 32%. Performance benchmarked with individual drilling parameters shows improved ROP response to WOB, RPM, and bit hydraulics in the optimized run.

This project solidifies machine learning as a powerful tool for bit selection and parameter optimization to improve drilling performance. Machine learning will become a significant part of well planning, design, and operations in the future. This study demonstrates how ANN's can be used to learn from previous operations and influence planning decisions to improve bit performance.
Application of Innovative Extended Reach Well Operation Technology in Nanhai East
Authors: Zhang Qiang , Zhang Weiguo , Qin Shili , Wei Yusen , Tian Bo , Jin Yong
Published: March 2021

Extended reach well (ERW) can be extremely drilled to distant reservoirs to reduce the infrastructure and operational footprint. Drilling ERW and extending their reach to greater depths requires both improved equivalent circulating density (ECD) and frictional resistance due to large horizontal displacement, long open hole and borehole unstability.

ECD is one of the keys to safe and efficient drilling, especially in complex formations with narrow pressure profile, and wellbore frictional resistance appreciably influences drilling torque and drag, as well as casing running. This paper presents several methods, including continuous circulating valve(CCV) drilling technology, cuttings bed removal technology and chemical friction reduction technology, to promote the success of ERW drilling. The applications are realized by means of adding CCV, cuttings bed cleaner to the drill string and chemical friction reducer into the drilling fluid.

Respectively the CCV drilling technology realizes the continuous circulation of drilling flooding, and cuttings bed removal technique utilize integrated design of hydraulic machinery with hydraulic parameter adjustment and flow passage design, to enhance turbulence velocity and strength of drilling fluid flow field, which both can effectively improve the efficiency of carrying bit cuttings, and reduce the fluctuation of ECD. Chemical friction reduction technology is mainly composed of chemical frictional drag reduction agent which belongs to organic anion compound products, and has excellent super anti-wear lubrication. Results show that the fluctuation of ECD in the high-risk well section with well loss was controlled within 2.5%, and narrow density window formation (0.18g/cm3) was drilled safely without any caving and leakage. The friction coefficient ranged from 0.4 to 0.25, with 40% decrease compared with previous wells in Huizhou Oilfield. And also the ROP increased by 45% due to effective transmission of WOB.

The technologies shown in this paper comprise key innovative technologies in ERW operation in Nanhai East. Less time is occupied in equipment installation, as well as simple operation flow, however with improved stability and remarkable performance. It lays a foundation for further study of ultra extended reach wells with greater difficulty and challenge.