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Abstract Wellbore instability is a major preoccupation during drilling operations and is highly dependent of the physiochemical features of the drilling mud. The hydrophilic clays are used in making drilling mud as they provide extensive viscosity and gel strength, and other rheological properties important for optimum drilling mud performance. However, the segregation of the suspended particles of the once optimum mud to create mud cake against the wellbore formation leads to phases imbalance in the mud system, degrading the physiochemical characteristics of the now worn-out mud after several cycling in and out of the well. Although it is crucial to consider the influence of bottomhole conditions in mud rheological alteration, it is necessary to highlight the direct correlation of most mud physiochemical features with the swelling index of the mud. Therefore, optimization of drilling mud is still up to date mostly about swelling control of the mud thus solid-liquid balancing. Overtime, research papers addressing drilling mud enhancement transitioned from mechanical means such as Loss Circulation Materials (LCM) to chemical additives including polymers which as economically profitable and have swelling abilities. Polyvinyl alcohol one most desirable polymers for future drilling fluid designing as it has proved to influence mud rheology and cake filtration positively. Therefore, this study is an attempt to assess the impact of polyvinyl alcohol on wellbore isolation of a water-based drilling mud. The experiment included two types of Polyvinyl Alcohol (PVOH): Non-ionic PVOH and Cationic PVOH. Each PVOH was added to a set of 3 samples at concentrations 0.1, 0.3, and 0.5 wt.%. An additional sample with no polymer was used as a reference sample. The samples were each subjected to 5h of static pressurized filtration at atmospheric temperature. After which Spectral analysis where performed, and Permeability estimated using Darcy's Law. The results show significant influence on Polyvinyl Alcohol on mud phases distribution. Major dehydration of samples was observed as the sample without PVOH recorded the highest filtrate production while the samples with Cationic, Non-Ionic, and Conventional PVOH had average reduction of 21%,38%, and 43% respectively. The mud cake permeability of samples drastically drops at the least concentration of PVOH with a noticeable difference in permeability despite having the same PVOH concentrations. Those differences are attributed to PVOH-specific structural compositions. This study provides evidence of Polyvinyl Alcohol being responsible for improving mud thermal stability while helping any industry applying drilling activities to expand the range of polymer types that can be used to attain the desired drilling mud for a particular formation.
- Asia > Japan (0.29)
- North America > United States (0.28)
- Research Report > New Finding (0.34)
- Research Report > Experimental Study (0.34)
- Asia > Middle East > Iraq > Basra Governorate > Arabian Basin > Widyan Basin > Mesopotamian Basin > Zubair Field > Zubair Formation (0.98)
- Asia > Middle East > Iraq > Basra Governorate > Arabian Basin > Widyan Basin > Mesopotamian Basin > Zubair Field > Mishrif Formation (0.98)
A Machine Learning Analysis to Relate Flow Pattern and Pressure Gradient During Gas Kicks Under Static Conditions
Obi, Chinemerem Edmond (Texas A&M University) | Falola, Yusuf (Texas A&M University) | Manikonda, Kaushik (Texas A&M University) | Hasan, Abu Rashid (Texas A&M University) | Rahman, Mohammad Azizur (Texas A&M University, Qatar)
Abstract Warning signs of possible kick during drilling operation can either be primary (flow rate increase and pit gain) or secondary (drilling break, pump pressure decrease,). Drillers rely on pressure data at the surface to determine in-situ downhole conditions while drilling. The surface pressure reading is always available and accessible. However, understanding or interpretation of this data is often ambiguous. This study analyses significant kick symptoms in the wellbore annulus while under shut-in conditions. We have tied several observed annular flow patterns to the measured pressure gradient during water- air, and water-carbon dioxide complex flow. This is based on experiments in a 140-ft high flow loop, with a hydraulic diameter of approximately 3 in. The experiments were carried out under static conditions to simulate kick occurrence when the drilling fluid is not flowing, typically the wellbore is shut-in. We used an Artificial Neural Network (ANN) and K-Means clustering approach for kick prognosis. We trained these Machine learning models to detect kick symptoms from pressure response and gas evolution data collected between the kick occurrence and the Wellhead. The Artificial Neural Network (ANN) approach was relatively fast with a negligible difference in accuracy when compared for air influx and carbon dioxide influx for kick prognosis. The ANN resulted in an accuracy of about 90% and 93% for air-based kick prognosis. While the accuracy was 92% and 94% for carbon dioxide-based influx. With K-mean clustering, the Silhouette score were 0.5 and 0.6 for the air and carbon dioxide influx respectively. The estimation of the influx size and type is strongly a function of the duration of kick and bottom hole underbalanced pressure. Based on visual analysis, pit gain, and pressure signals, the quantity of the mass influx significantly controls the flow pattern, pressure losses, and pressure gradient as the kick migrates to the surface. The resulting turbulent flow after the initial kick (After Taylor bubble flow) varied with duration of kick, average liquid flow rate, influx type, and drilling scenario. We have tied the surface pressure readings to the flow regimes to better visualize well control approach while drilling. This is based on relating the significant kick symptoms we observed to the pressure readings at multiple locations and time, then training the Deep learning models based on this data. Although computationally demanding, the Deep-Learning model can use the surface pressure data to relay annular flow patterns while drilling. This work provides an alternative and relatively accessible primary kick detection tool for drillers based on measured pressure responses at the surface.
- Well Drilling > Pressure Management > Well control (1.00)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring > Production logging (1.00)
- Data Science & Engineering Analytics > Information Management and Systems > Neural networks (1.00)
- Data Science & Engineering Analytics > Information Management and Systems > Artificial intelligence (1.00)
Abstract Gas kick is an undesirable problem in the drilling process, which can potentially lead to a blowout. The primary intent of this study is to highlight gas migration and its effect on gas kick mitigation approaches that would benefit the drilling process. The integrated analysis provides valuable insight regarding parameters promoting efficient drilling processes, minimizing the risk of gas kicks. This study aimed to investigate the impact of critical parameters on gas migration during the gas kick in both water-based mud and oil-based mud and to promote an understanding of the dynamics of choke pressure, gas velocity, and bottomhole pressure based on completion and reservoir parameters. This study reveals various factors affecting gas migration during gas kicks, characterized by different interactive parameters. These parameters include wellbore configuration, mud density, kick volume, drill-pipe size, reservoir temperature, and oil-water ratios. A commercial multiphase dynamic well control simulator was used in this study to develop two base models: Oil-Based mud (OBM) and Water-Based mud (WBM). The models were used to perform several parametric studies to investigate the impact of critical parameters on gas migration during the gas kick. Each type of mud acted differently and affected the gas migration discussed in this study. The study explicitly illustrates the different outcomes for each model during gas migration. The parameters that range from most effective to least effective on gas migration are wellbore configuration, kick volume, drill-pipe size, mud density, and reservoir temperature in WBM, while in the OBM, the parameters that range from most effective to least effective are wellbore configuration, kick volume, drill-pipe size, oil-water ratio, mud density, and reservoir temperature. However, the main differences are the gas rise velocity and time in the base models. In water-based mud, the gas velocity is 97.8 ft/min, while the gas velocity in oil-based mud is 75.6 ft/min. The gas is discharged from the well within 48.2 minutes in the water-based mud, while the oil-based mud takes 115.7 minutes.
Minimizing Lost Circulation Non-Productive Time Using Expected Monetary Value and Decision Tree Analysis
Alkinani, Husam Hasan (Missouri University of Science and Technology) | Al-Hameedi, Abo Taleb Tuama (Missouri University of Science and Technology) | Dunn-Norman, Shari (Missouri University of Science and Technology)
Abstract Lost circulation and problems related to drilling present a major challenge for the drilling industry. Each year, billions are spent to treat these problems. There is not a single solution to lost circulation because of the complexity and kind of formations susceptible to this issue. Lost circulation treatment data for the Shuaiba formation (induced fractured formation) were gathered from drilled wells in Southern Iraq (over 2000). Treatments have been grouped according to the volume of mud loss as complete, severe, and partial loss remedies. Detailed costs and probabilities calculations were conducted. The costs of three types of loss treatments (partial, severe, and complete) were handled separately since some treatments of severe, and all treatments of complete losses have to be introducing through open end drill pipe (OEDP). Expected monetary value (EMV) and decision tree analysis (DTA) were utilized to choose the optimal mud loss pathway to treat the lost circulation type. In this study, probability and cost were both considered to select the practical and efficient strategy of stopping mud loss. Too many of the remedy scenarios were investigated. The selection of the optimum strategy for every type of loss was based on the lowest EMV and efficiency. Once both conditions were satisfied, the treatment strategies were selected to treat each type of loss. Treatment strategies were provided for complete, severe, and partial losses as flowcharts that can be utilized as a reference in the field to stop or at least mitigate this troublesome problem. The methods used in this paper have the possibility to be adopted and invested to treat mud loss based on historical data of treatments in any formation worldwide.
- Asia > Middle East > Iraq > Thamama Group > Shu'aiba Formation (0.99)
- Asia > Middle East > Iraq > Basra Governorate > Arabian Basin > Widyan Basin > Mesopotamian Basin > Rumaila Field > Zubair Formation (0.99)
- Asia > Middle East > Iraq > Basra Governorate > Arabian Basin > Widyan Basin > Mesopotamian Basin > Rumaila Field > Shuaiba Formation (0.99)
- (5 more...)
Updated Classification of Lost Circulation Treatments and Materials with an Integrated Analysis and their Applications
Alkinani, Husam H. (Missouri University of Science and Technology) | Al-Hameedi, Abo Taleb (Missouri University of Science and Technology) | Flori, Ralph E. (Missouri University of Science and Technology) | Dunn-Norman, Shari (Missouri University of Science and Technology) | Hilgedick, Steven A. (Missouri University of Science and Technology) | Alsaba, Mortadha T. (Australian College of Kuwait)
Abstract Lost circulation materials (LCM's) have been widely used to avoid or stop losses. Due to a large number of currently available materials, treatments, and their different applications, classification of them is very important. The most recent materials and treatments classification was published a long time ago. This paper intends to present an updated classification including conventional and new technologies. Here, LCM's are re-classified based on their appearance, applications, and chemical and physical properties. Lost circulation control during well construction is more than just selecting the right lost circulation material (LCM), but requires a complete engineered approach. This paper was developed mostly based on the literature with real field data from various Basra's oil fields. More than 200 technical journals papers, textbooks, case histories, real field data, and manuals that address the problem of lost circulation are carefully reviewed and summarized. Lost circulation materials and treatments are extracted from the literature. The results from the lab are compared to what was applied to many oil fields including 800 wells drilled in Basra's oil fields. A new classification for lost circulation treatments and materials is developed. Unlike the current classification, the new classification is based on the applications. Conventional LCM's are currently classified into different categories based on their appearance as fibrous, flaky, and granular or a blend of all three. This paper classifies the lost circulation materials and treatments as corrective and preventive approaches. The corrective treatments can be applied after the occurrence of the lost circulation; however, the preventive techniques can be applied before entering losses zones as a proactive action. The most recent developments in lost circulation materials and treatments have been discussed, in addition to the presentation of a comprehensive summary of today's available LCM's, treatments and alternative approaches with their applications. This paper discusses the most recent developments in materials and treatments with their applications. Treatments and materials are tabulated for each type of losses to provide effective remedies and minimize NPT and cost. The purpose of this study is to develop practical guidelines that are general and not biased towards a particular service company product which will also serve as a quick reference guide for lost circulation prevention and control at the well-site for drilling personnel.
- Europe (1.00)
- North America > United States > Texas (0.69)
- Asia > Middle East > Iraq > Basra Governorate > Basra (0.46)
- Overview (0.54)
- Research Report (0.48)
- Asia > Middle East > Iraq > Basra Governorate > Arabian Basin > Widyan Basin > Mesopotamian Basin > Rumaila Field > Zubair Formation (0.99)
- Asia > Middle East > Iraq > Basra Governorate > Arabian Basin > Widyan Basin > Mesopotamian Basin > Rumaila Field > Shuaiba Formation (0.99)
- Asia > Middle East > Iraq > Basra Governorate > Arabian Basin > Widyan Basin > Mesopotamian Basin > Rumaila Field > Nahr Umr Formation (0.99)
- Asia > Middle East > Iraq > Basra Governorate > Arabian Basin > Widyan Basin > Mesopotamian Basin > Basra Field (0.98)
Abstract Lost circulation is a very common and expensive problem during drilling and cementing operations in the oil and gas industry. The lost circulation problems encountered during drilling or cementing are a result of one of two factors. These factors are the presence of zones of weak fracture gradients and the presence of high permeability or thief zones downhole. Light weight cements are an effective solution for curbing lost circulation caused by the breakdown of weak zones by conventional cement slurries. This paper presents a discussion of the different methods, additives and technologies that have been and are currently employed in the formulation of lightweight and ultra-lightweight cement slurries for cementing oil wells as well as recent developments based on an extensive literature review. This paper also discusses the mechanical performance, cost effectiveness and field logistical considerations of lightweight slurries formulated using different methods as these are important factors that impact decision making on what slurry extension method to choose for any given scenario. The information presented in this paper is derived from an extensive review of information contained in papers, journals and books spanning the last 50 years of well cementing and is summarized in such a way that the paper serves as a quick guide to cement slurry extension technology and techniques. An extensive review of the literature regarding lightweight cements showed that there are three general methods of obtaining lightweight cement slurries. These methods include increasing cement slurry water content (water extension) with the aid of viscocifying agents such as bentonite and sodium metasilicate, adding lightweight materials like glass microspheres and incorporating foam into slurries. Reported test data shows that apart from cement slurries containing glass microspheres and foamed cements, lightweight slurries exhibit lower compressive strength and slower compressive strength development than heavy slurries. Foamed cements pose the greatest design and field logistics challenge while cement slurries with glass microspheres have gained more popularity due to the excellent compressive strength values achievable at ultra-low densities despite their higher cost compared to water-extended slurries and lightweight slurries containing other lightweight additives like fly ash. The literature review presented also indicates a need for more research into improving lab mixing and testing methods that replicate field applications of foam cement. There is also a need for research into more cost-effective slurry extension additives and technology that exhibit acceptable mechanical performance for well integrity assurance and rheological properties favorable to proper cement placement in the annulus.
Abstract The analysis of previous (offshore) oil and gas drilling accidents indicates that Human and Organizational Factors (HOFs), in addition to technology- and work processes-related elements, play a critical role in contributing to those accidents. These HOFs are originated from different layers of key involved decisions-makers, both internal and external to an organization. This paper proposes a system-oriented methodology for the risk analysis of oil and gas drilling industry by integrating the two powerful frameworks of AcciMap and Bow-tie. In the first phase, the AcciMap framework, which was originally proposed by Professor Jens Rasmussen in 1997, is used as a systematic accident investigation methodology for the analysis of the BP Deepwater Horizon (DWH) blowout, as a case study. This graphical representation, by incorporating associated socio-technical factors into an integrated framework, provides a big-picture to illustrate the context in which an accident occurred as well as the interactions between different levels of the studied system that resulted in that event. In the next phase, the results from analyzing the BP DWH accident using the AcciMap framework are used as a foundation for the development of a Bow-tie model. This model, as a barrier-based risk assessment framework, introduces both preventive and mitigation barriers that by incorporating them into an analyzed system, respectively, the likelihood of occurrence of future accidents and their negative consequences will be reduced. The analysis of the BP DWH accident indicates that aside from influencing external components, organizational factors such as economic pressure as well as communication and interoperability issues, both in regular and emergency situations, were the root contributing causes of this accident. This analysis is then used for the identification and development of appropriate barriers in our proposed Bow-tie framework. In addition to organizational factors, human factors and technological elements have contributed to this accident and other cases. Those are also identified and used to develop approporiate barriers in our Bow-tie framework. The integration of the two frameworks of AcciMap and Bow-tie, which are compatible with each other and complement each other, provides a novel comprehensive perspective to better analyze operations in high-risk systems such as the oil and gas drilling industry. It is noteworthy that although the utilized AcciMap framework was developed for the analysis of the BP DWH blowout, our defined preventive and mitigation barriers in our Bow-tie framework are generalized to represent other (offshore) oil and gas drilling cases as well. Therefore, our proposed integrated methodology can be used for the risk assessment of operations in the entire (offshore) oil and gas drilling industry. Furthermore, this paper and its proposed methodology provides a roadmap that can be adopted by any safety-critical industry; e.g. petrochemical processing, transportation and nuclear power, for the risk analysis of its operations.
- Europe (1.00)
- North America > United States > California > Los Angeles County (0.46)
- Energy > Oil & Gas > Upstream (1.00)
- Government > Regional Government > North America Government > United States Government (0.46)
Abstract The investigation of different accidents in offshore oil and gas drilling industry indicates inadequate management systems and miscommunication as one of the major contributing factors leading to these accidents. In this paper, we will identify the common contributing factors of three major offshore oil and gas drilling accidents in the period of 2009 to 2013 using the structure of the AcciMap methodology, as a risk management and accident investigation framework that was developed by Rasmussen in 1997. This methodology analyzes the contribution of different socio-technical factors and involved key players in an accident through its hierarchical structure. This provides a broader perspective to investigate accidents and identify their common contributing factors. The two analyzed accidents in this paper are the Hercules 265 Jack-up Rig Blowout in 2013 and the Montara Oil Spill in 2009 using the structure of the AcciMap framework. The results of this analysis will then be compared with the already developed AcciMap framework by Tabibzadeh and Meshkati (2015) for the BP Deepwater Horizon blowout to find the similarities among these accidents. One of the important findings about these accidents is the fact that they did not occur as the act of individuals (we cannot blame front-line operators), but rather due to highly responsive and combined processes, which involve decisions of several layers of key players. In this chain, companies and their policies affect their management's plans and decisions. These decisions are passed on to lower levels and impact personnel's (crew's) actions, which eventually along with existing processes and conditions could lead to disasterous accidents. In addition, government and regulatory agencies as well as industry codes, standards and best practices, as external factors, play a role in contributing to accidents. Moreover, the analysis of the comparison of the three aforementioned accidents shows that how lack of proper, standard well control procedures and guidelines or lack of knowledge about them when combined with ineffective communication and interoperability can prove to be deadly and harmful in different ways. It causes loss of life, property and revenue. In addition, it endangers the environment, which is already suffereing due to other human activities.
- Oceania > Australia (1.00)
- Europe (0.68)
- North America > United States > California > Los Angeles County (0.28)
- Government > Regional Government > North America Government > United States Government (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Oceania > Australia > Western Australia > Timor Sea > Bonaparte Basin > Vulcan Basin > PL AC/L8 > Montara Field (0.99)
- Oceania > Australia > Western Australia > Timor Sea > Bonaparte Basin > Vulcan Basin > PL AC/L7 > Montara Field (0.99)
- North America > United States > Gulf of Mexico > Central GOM > East Gulf Coast Tertiary Basin > South Timbalier Area (0.99)
- (2 more...)
- Well Drilling > Pressure Management > Well control (1.00)
- Well Drilling > Drilling Operations (1.00)
- Management > Risk Management and Decision-Making (1.00)
- (4 more...)
Abstract Lost circulation represents a very costly, time consuming challenge to drilling through depleted geological zones that has proven difficult to accurately predict and manage. The standard approach relies on the driller's experience with the field to know how best to treat lost circulation when it occurs, or better yet, avoid it altogether, usually by enforcing maximums and minimums to various drilling parameters. This approach, however, ignores the key interplays between all of the variables involved, geological and reservoir performance information in addition to drilling data, where a change in one variable may affect the safe operating range of another. Taking all variables into account can be a prohibitively arduous task, particularly while managing the many other demands of drilling operations. Fortunately, a computer can quickly make all of the necessary calculations, and with programs designed to mimic human decision-making, can even make recommendations. The aim of this project was to create a program that would take into account all of the key variables related to lost circulation and provide drillers in the field on-the-spot recommendations as to the most successful method of remediation, and to provide proof of concept that a such programs could be created to help prevent lost circulation in the first place. The objective was achieved by creating a system using Case-Based Reasoning, which reviews a database of past incidents, determines those most similar in nature, and provides recommendations based on previous successes and failures. This program, when run on test cases, was able to accurately recommend the proper lost circulation remedial method. This paper will cover details on the types of data used, the operating mechanics of this system, example cases, and a detailed breakdown of the results.
Abstract Recently it has been demonstrated that flowback data obtained immediately after fracture stimulation of multi-fractured horizontal wells (MFHWs) completed in tight/shale reservoirs may be analyzed quantitatively for hydraulic fracture properties. However, the initial conditions of fluid pressures and saturations at the start of flowback, which are a critical starting point for flowback simulation, are generally unknown and must be approximated. In order to properly initialize flowback simulations, the pre-flowback fracture stimulation treatment, as well as post-treatment shut-in period, should first be modeled in order to provide a reasonable estimate of fluid pressures and saturations within the hydraulic fracture and adjacent reservoir. In recent work, the authors developed a semi-analytical model to history-match flowback and early-time production data of MFHWs completed in tight oil reservoirs using the "dynamic drainage area" (DDA) concept. The model assumes that each fracture stage consists of a primary hydraulic fracture (PHF) region, and an adjacent enhanced fracture region (EFR) or non-stimulated region (NSR) in the reservoir. However, initial fracture fluid pressure in the PHF, and fluid pressure/saturation distributions in the adjacent EFR/NSR are required for the model initialization and are highly uncertain. In the current work, flowback data from a previously-analyzed MFHW horizontal well completed in a tight oil reservoir is revisited to determine if flowback initial conditions could be constrained rigorously. For this purpose, frac modeling (net-pressure analysis) was first performed using fracture treatment data for the well and commercial and publically-available simulators to constrain PHF property input for the DDA flowback model. The DDA model, run in injection mode, was then used to calculate the frac fluid leakoff rate from the PHF to the NSR during the fracture treatment, using the field frac pressures as input. Importantly, leakoff is modeled more rigorously using the DDA model than for the frac simulator, because it accounts for two-phase flow and stress-dependent permeability. Leakoff after the fracture treatment and before the flowback period was also modeled using the DDA approach to estimate the pre-flowback NSR fluid saturations and pressures, which served as the initial conditions for flowback modeling. The amount of leakoff estimated with the model is relatively small in this case, in part due to the small volumes of fluid used in the fracture treatment and low permeability of the reservoir. The resulting flowback history-match (also performed using the DDA model, in flowback mode) is similar to that achieved previously because the pre-flowback leakoff modeling resulted in only a slightly elevated water saturation estimate over virgin reservoir conditions. The results of this innovative approach to flowback modeling should be of interest to those petroleum engineers interested in quantitative analysis of flowback data to obtain fracture properties, but who are concerned about correct initialization of models for flowback simulation leading to more realistic results.
- North America > United States > California (0.46)
- North America > United States > Texas (0.28)