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Decisions in E&P ventures are affected by Bias, Blindness, and Illusions (BBI) which permeate our analyses, interpretations and decisions. This one-day course examines the influence of these cognitive pitfalls and presents techniques that can be used to mitigate their impact. Bias refers to errors in thinking whereby interpretations and judgments are drawn in an illogical fashion. Blindness is the condition where we fail to see an unexpected event in plain sight. Illusions refer to misleading beliefs based on a false impression of reality. All three can lead to poor decisions regarding which work to undertake, what issues to focus on, and whether to forge ahead or walk away from a project. Strategic thinking and planning are key elements in an organisation’s journey to maximise value to shareholders, customers, and employees. Through this workshop, attendees will go through the different processes involved in strategic planning including the elements of organisational SWOT, business scenario and options development, elaboration of strategic options and communication to stakeholders. Examples are provided including corporate, business unit and department case studies. This seminar will teach participants how to identify, evaluate, and quantify risk and uncertainty in everyday oil and gas economic situations. It reviews the development of pragmatic tools, methods, and understandings for professionals that are applicable to companies of all sizes. The seminar also briefly reviews statistics, the relationship between risk and return, and hedging and future markets.
This seminar will teach participants how to identify, evaluate, and quantify risk and uncertainty in everyday oil and gas economic situations. It reviews the development of pragmatic tools, methods, and understandings for professionals that are applicable to companies of all sizes. The seminar also briefly reviews statistics, the relationship between risk and return, and hedging and future markets. Strategic thinking and planning are key elements in an organisation’s journey to maximise value to shareholders, customers, and employees. Through this workshop, attendees will go through the different processes involved in strategic planning including the elements of organisational SWOT, business scenario and options development, elaboration of strategic options and communication to stakeholders. Examples are provided including corporate, business unit and department case studies. Safety leadership focuses on the Human Factors (HF) which complement technical training to optimise reliability, safety, compliance, efficiency, and risks within a team-based environment. The IOGP laid down the HF skills and competencies required, and they form the basis for specialised O&G HF training's delivered by Mission Performance. This 1-day course reviews the key human factors but then also reviews what can be done to accelerate and scale operational roll-out for optimum and sustained impact, including integration with existing safety processes and (reporting) systems, refreshers, assessments, measurements, as well as the role of leadership and culture. Decisions in E&P ventures are affected by Bias, Blindness, and Illusions (BBI) which permeate our analyses, interpretations and decisions. This one-day course examines the influence of these cognitive pitfalls and presents techniques that can be used to mitigate their impact. Bias refers to errors in thinking whereby interpretations and judgments are drawn in an illogical fashion.
Wu, Jiwei (East China University of Science and Technology, Harvard University) | Lin, Haitao (East China University of Science and Technology) | Huang, Yuan (East China University of Science and Technology) | Wang, Hualin (East China University of Science and Technology) | Zhou, Shouwei (China National Offshore Oil Corporation) | Fu, Qiang (China National Offshore Oil Corporation)
Natural gas hydrate is a key future clean energy resource, and sand control is crucial in natural gas hydrate production. However, the sand control is still inefficient, which impedes industrialized development of natural gas hydrate. From production test carried out in the South China Sea, we found the separation of micrometer-sized sand from the fluid is the main challenge in sand control. Based on high-speed motion in our 3D rotating turbulent flow field of hydrocyclone, our study presents a new technology to realize efficient separation of micrometer-sized sand and breaking consolidation between hydrate and sand. As results of hydrocyclone separation experiments, we have the high separation efficiency that is up to 92.23% for silica sand and 98.87% for PP; also only 0.46% 1.05% of PP powder remains in recovered materials. In conclusion, the technology proves the ability of breaking-consolidation and realizes the goal of separation of micrometer-sized particles, and thus improve the sand control in exploitation of marine natural gas hydrate.
An advanced gas analysis heated system (AGAHS) analyzes the gas extracted from a water-based mud (WBM) to estimate the hydrocarbons contents in drilled rock formations. Operating conditions within the gas-extraction device (gas trap) such as the gas concentration in the mud, stirring velocity, mud-flow rate and temperature, and ditch-line flow rate and pressure are studied to maximize the gas-extraction efficiency in the gas trap. The operating conditions that most affect the gas-extraction efficiency are the stirring velocity and the mud-flow rate. The highest and most stable gas-extraction efficiencies are obtained at 1,680 rev/min and 1.0 L/min.
Investigation of the effectiveness of matrix-stimulation treatments for removing drilling-induced damage in the Akita region of northern Japan is of interest because of the presence of large quantities of acid-sensitive minerals, such as analcime. A feasibility study of the subcommercial field redevelopment in the Kita-Akita Oil Field, one of the satellite fields of the main Yabase Oil Fields that produced from 1957 to 1973 and was plugged and abandoned, was conducted. As a part of the studies, matrix-acidizing laboratory experiments were performed. Conventional mud acids and formic-acid-based organic-mud-acid systems cause significant permeability damage because of the instability of analcime when exposed to these acids. This study focuses on the development of a treatment fluid that removes drilling-induced damage and is also compatible with the formation.
Petrology studies and core flow tests were used in conjunction with geochemical modeling to achieve this objective. A petrographic analysis on the untreated cores showed abundant tuffaceous pore-filling mineral phases, ranging from 12 to 20% in volume. Smectite clay and microcrystalline quartz are the major constituents present as alteration products of volcanic glass. Analcime was present in significant quantities in all samples tested.
Six core flow tests were performed on formation cores to optimize the acid preflush and main acid stage. Permeability change resulting from treatment fluids was recorded for the tests. Chemical analysis of the effluent was performed on three core flow tests. Core samples before and after acidization were characterized on the basis of thin section, X-ray diffraction (XRD), scanning electron microscopy (SEM), and mineral mapping.
Core flow tests with conventional retarded organic mud acid (ROMA) resulted in only 75% retained permeability. The permeability damage by the ROMA was surprising, because it usually performs well in acid-sensitive formations. A chelant-based retarded mud acid was tested next and resulted in minor formation damage. It can be potentially used in a field treatment, because its high dissolving power is expected to more than compensate for the damage. The highest retained permeability was obtained with an acetic-hydrofluoric (HF) acid system. It was successfully able to remove drilling-induced damage and was also compatible with the native mineralogy. Core flow tests were used to calibrate the permeability/porosity relationship used in the geochemical simulator. The geochemical simulator was then used to predict the field-level acid response.
The analytic methods presented are general enough to be of interest to sandstone-acidizing studies, where detailed analysis is needed for damage identification and removal. The fluids developed for this formation are good candidates for other formations where conventional acid systems have not performed well. This study also highlights a close collaboration between the operator and the service company to find a workable solution to a challenging stimulation requirement.
Lei, Ting (Schlumberger-Doll Research) | Zeroug, Smaine (Schlumberger-Doll Research) | Bose, Sandip (Schlumberger-Doll Research) | Prioul, Romain (Schlumberger-Doll Research) | Donald, Adam (Schlumberger-Doll Research)
Interpretation of elastic properties honoring fine heterogeneity has garnered recognition recently in petrophysical analysis, bedding failure prediction, and hydraulic fracture job design for unconventional reservoirs. Traditional sonic log processing assumes homogeneity of the formation over a specific sonic tool receiver aperture length, e.g., at least 2 ft. This assumption may not be appropriate for highly laminated reservoirs. Additionally, shear slownesses extracted from low- and high-frequency processing are associated with different wavelengths and different rock volumes. Shear slowness logs from a high- frequency monopole transmitter and a low-frequency dipole flexural mode can exhibit different axial resolutions even when using the same receiver aperture length.
We developed a new interpretation algorithm to improve the layer slowness contrast for thinly laminated formations in vertical wells using borehole sonic data from array-based logging tools equipped with either a monopole, dipole, or a quadrupole transmitter. This novel interpretation method can yield high-quality high- resolution sonic compressional and shear logs. It is based on a robust deconvolution technique that jointly combines all logs processed at different array resolutions. This method yields the sonic log with an optimal apparent resolution better than that estimated from the conventional 1-ft single-resolution subarray method. Finally, the residual is formulated to serve as a log quality-control flag and can be used to switch to more reliable low-resolution logs in depth intervals of poor-quality hole data.
The algorithm was validated with synthetic logs from finite-difference modeling and was then tested on a field dataset collected in a vertical well traversing a thinly laminated formation. The resolution of deconvolved compressional and shear logs from field measurements exceeds that from conventional processing, and is consistent with a higher resolution ultrasonic log from an ultrasonic imaging tool logged in the same well. The field- data application suggests that this deconvolution algorithm enhances the spatial resolution and more accurately captures the layer slowness contrast while removing outliers thereby improving the log quality.
The application of this method results in a superior characterization of the acoustic properties of thinly layered rocks relative to that from conventional processing. The estimated elastic moduli could improve stress profiling and rock-strength correlations for geomechanical modeling.
Submarine hydrothermal ore-deposits are known to be rich in metal resources and are to be found abundant around the Japanese islands. In recent years, several field studies had been carried out and a lot of data on chemical and physical properties of geological samples (ore-deposits, rocks, sediments) have been gathered especially for hydrothermal fields in the Okinawa Trough. However, the mechanism of formation and accumulation of these deposits is not yet clearly understood. In this study, we investigated hydrothermal fluid flow in combination with chemical reactions of a simplified model (2-dimensional radial model) representing hydrothermal activity around a vent fluid conduit beneath the seafloor. The numerical code TOUGHREACT V3.0 - OMP, which is for coupled non-isothermal multiphase fluid flow and geochemical reactive transport was employed. Almost all model parameters are chosen based on available results of geophysical and geochemical surveys of the Iheya hydrothermal fields in the Okinawa Trough. Therefore, the geological structures were set as having diverse permeability, which reflects alternating pumiceous volcaniclastics layer and hemipelagic sediment layer. Chemical reactions including precipitation of minerals (anhydrite, quartz and sphalerite) caused by mixing of hydrothermal fluid and seawater-derived fluid and/or cooling was considered in this setting. Following two features were clarified: First, high velocity venting hydrothermal fluid ascends to the seafloor through the fluid conduit at the center of the model, whereas nearby cold water percolates downward from the seafloor and convection occurs. Second, among the alternating layer structure, preferential horizontal flow is obvious for layers with high permeability, which resulted in primary sulfide precipitation with a lateral extend. These results are likely to be consistent to recent field studies during scientific drilling into the submarine hydrothermal fields.
Submarine hydrothermal ore-deposits are known to be rich in metal resources and are to be found abundant around the Japanese islands. In recent years, a lot of data on chemical and physical properties of submarine hydrothermal ore-deposits in the Okinawa Trough have been gathered due to several field surveys.
Nagata, Masashi (Central Nippon Expressway Company Limited) | Bhowmik, Sharmily (Yokohama National University) | Kikumoto, Mamoru (Yokohama National University) | Fujiwara, Yu (West Nippon Expressway Company Limited) | Sato, Naohiro (Meiji Consultant Company Limited)
Weathering of geomaterials causes degradation of the material, resulting in a surficial collapse in cut slopes. Thus, slope protection methods such as vegetation and shotcrete are empirically applied to retard the weathering. The weathering mechanism has not been fully understood, and the prediction of the progress of the weathering is still challenging. Therefore, we selected 96 cut slopes on Japanese highway routes and have tried to grasp the progress of weathering of the slopes through field surveys such as elastic wave exploration tests. In this study, a cut slope consisting of mudstone on Tomei Expressway in Yoshida, which exhibited a localized collapse in 2016, was studied to investigate the weathering state of the ground. This slope was constructed in 1968 and has experienced more than 50 years after construction. The objectives are to investigate the spatial distribution of the weathering magnitude of the cut slope and to grasp the weathering effect on mechanical properties of rock such as strength and stiffness.
Since the Meishin Expressway was opened in 1965, Japan's expressways have been developed nationwide. The total extension has reached to about 9000 km, 74 % of which consists of soil structures as embankments and cut slopes. As about half of the expressway has experienced more than 30 years of in-service period, several technical issues have arisen gradually due to the aging of the ground. Thus, to maintain the existing highway assets effectively, it is quite necessary to grasp the long-term weathering behavior of the ground.
In this study, we focus on the long-term behavior of cut slopes. Most of the cut slopes remained stable for several decades after the construction. However, weathering of the ground gradually progresses in some of the slopes and eventually caused instability issues such as surface collapse. Thus, in order to clarify the weathering mechanism of the cut slopes, we carried out field surveys on 96 cut slopes nationwide using elastic wave exploration repeatedly for about forty to fifty years since the opening of the expressways (Fujiwara, 2018). We previously reported that the elastic wave velocity near the surface tends to decrease and the thickness of the weathered layer tends to increase with the progress of weathering (Fig. 1) (Nagata, 2019). In this paper, we discuss the mechanical and chemical consequences of the weathering of the cut slope consisting of mudstone through the results of physical tests and X-ray diffraction analysis on the boring cores collected from one of the target cut slopes.
Barros, Adelson (Adnoc Offshore) | Alaleeli, Ahmed Rashed (Adnoc Offshore) | Hamidzada, Ahmedagha (Adnoc Offshore) | El Hassan, Azza (Adnoc Offshore) | Melo, Alexandre (Adnoc Offshore) | Orfali, Mohd Waheed (Schlumberger) | Phyoe, Thein Zaw (Schlumberger) | Salazar, Jose (Schlumberger) | Kapoor, Saurabh (Schlumberger) | Kondo, Kazuyoshi (Schlumberger)
Lost circulation (LC) is an expensive and time-consuming problem. It's desirable to minimize losses before cement job to ensure good cement coverage and maximize well integrity. But quite commonly, wells experience induced losses just before cementing, during casing running and circulation. In such a scenario, the options to control losses have been few, with limited results. The paper demonstrates a viable solution that can be successfully applied to reduce or eliminate such induced losses during the cement job.
To effectively solve lost circulation with the correct technique, it is necessary to know the severity of the losses and the type of lost circulation zone. In UAE fields, the loss rates range from 150 bbl/h to more than 700 bbl/h in the 17½- and 12¼-in open hole sections. During cementing operations, lost circulation causes reduced top of cement, poor zonal isolation, and risks to drill ahead. To solve this problem, a composite fiber-based spacer system based on a novel four-step methodology was designed using advanced software. Before a field trial, rigorous lab-scale and yard-scale testing was conducted to optimize the application.
Initially, no losses were witnessed while drilling the 12¼-in section. But during casing running and circulation, severe losses of 150 bbl/hr were induced. To counter these losses, the specially designed fiber-based lost circulation spacer system was pumped ahead of the cement slurry using standard surface equipment. At the beginning of the displacement—while cement and spacer were still in the casing string—the loss rate increased to 700 bbl/hr (total losses). This high loss rate in the crucial intermediate section would normally have resulted in costly remedial operations, loss of mud and cement, and expensive rig time. It was observed that the loss rate remained at 700 bbl/hr until the lost circulation spacer arrived at the loss zone. Subsequently, the loss rate kept on declining finally resulting in full returns during remaining displacement. The designed excess of cement was received as returns, thereby ensuring the desired top of cement at surface. This proved that the fiber-based spacer was effective in curing the losses. An advanced cement bond log showed complete cement coverage over the entire section. This further proved the spacer's effectiveness in achieving all well integrity objectives.
The successful application of the engineered fiber-based lost circulation control spacer during primary cementing demonstrates a reliable solution to the challenge posed by losses induced immediately before a cement job. The system is easy to deliver and design and can plug the fracture network in the formation during the cement job. Globally, this engineered composite fiber-blend spacer has proved to improve performance during cementing operations by healing losses to maximize well integrity.