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Equinor
Understanding the synergistic impact of stress release and cementation on sandstone using sound waves — Implications for exhumation estimation
Yu, Jiaxin (Norwegian University of Science and Technology) | Duffaut, Kenneth (Equinor) | Avseth, Per (Dig Science, Norwegian University of Science and Technology)
ABSTRACT Exhumation is the process that encompasses uplift and erosion, leading to the removal of overburden and the release of effective stress exerted on rocks. When estimating exhumation magnitude using the compaction trend method, it is commonly assumed that the physical properties of rocks are insensitive to stress reduction. However, recent laboratory evidence has indicated that porosity exhibits weaker sensitivity to stress release compared with velocity that can be significantly affected by stress release. This raises questions regarding the validity of irreversible compaction assumed by compaction trend method. It remains unclear whether the impact of stress release can be observed in real rocks in exhumed areas because there is a lack of methods to directly measure the impact of stress release on field data. In addition, studying real rocks is further complicated by the presence of rock diagenesis and its interaction with stress release. To address these knowledge gaps, this study uses stress-dependent burial and uplift modeling and interprets an extensive well-log data set using the modeling-derived evaluation metrics. Conceptual modeling suggests that methods that neglect the combined effect of cementation and stress release tend to underestimate the exhumation magnitude. Furthermore, we discover that the disparity between porosity sensitivity and velocity sensitivity to stress release can be leveraged to derive a metric we call “porosity inconsistency” that can serve as a qualitative and quantitative measure for identifying and evaluating stress release in sandstone using geophysical field measurements. We gather a significant amount of sonic velocity and porosity data from normally compacted and uplifted clean sandstones in the Norwegian Sea and the Barents Sea. Notably, we observe significant porosity inconsistency in the exhumed well 6510/2-1 in the Norwegian Sea. In the Barents Sea, which has experienced extensive Cenozoic exhumation, the well data reveal a varying pattern of porosity inconsistency increasing toward the north and decreasing toward the west. This distribution of porosity inconsistencies in the Barents Sea wells not only aligns with the spatial variation of exhumation reported in various studies but also exhibits a positive correlation with the magnitude of exhumation. Furthermore, the exhumation magnitude derived from velocity-depth trends is considerably lower than the magnitude obtained from porosity/density-depth trends for wells displaying significant porosity inconsistency. These observations provide support for the predictions made by the conceptual modeling. The results of this study enhance our understanding of the synergistic impact of stress release and cementation on sandstone. Moreover, these findings have implications for pore pressure prediction and core evaluation in exhumed areas. They also provide insights into the feasibility and interpretation of time-lapse data of reservoir injection, for which the effective stress is likely to decrease due to pore pressure buildup.
- Europe > Norway > Norwegian Sea (0.68)
- Europe > United Kingdom (0.68)
- Phanerozoic > Cenozoic (1.00)
- Phanerozoic > Mesozoic > Jurassic (0.93)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Sandstone (1.00)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (0.48)
- Geophysics > Seismic Surveying > Seismic Modeling > Velocity Modeling (0.93)
- Geophysics > Borehole Geophysics (0.67)
- Oceania > Australia > Western Australia > Perth Basin (0.99)
- Oceania > Australia > Victoria > Otway Basin (0.99)
- Oceania > Australia > South Australia > Otway Basin (0.99)
- (12 more...)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Reservoir geomechanics (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Geologic modeling (1.00)
- (3 more...)
Abstract Accurate level measurement in process vessels is important for safety, production optimization and control as well as for optimization of chemical additives. Most of the level measurement sensors used in oil and gas production today are Differential Pressure (DP) transmitters, displacers and, sometimes, Guided Wave Radar (GWR). More advanced profiler-type sensors are used more rarely and most often only for process analytics. Almost all of the commercially available level measurement instruments are intrusive, meaning that they require a flange or penetration for installation and maintenance. In practice, this implies that installation and maintenance on an existing installation have to be conducted during a turnaround. This makes such a project prohibitively expensive considering the cost of turnaround time and the fact that a turnaround on an offshore platform is only performed once every 1-4 years. This work describes pilot trials with a novel non-intrusive level measurement system that utilizes Guided Elastic Waves (GEW) for attenuation tomography. Pilot experiments were carried out in a model separator with an internal diameter of 1.00 m and length 3.75 m. The pilot separator which was filled to pre-determined levels with tap water, mineral oil and construction sand. Flow of water was induced in some of the experiments. Phase levels were recorded manually through a sight glass and compared to readings generated by the novel measurement system. Experiments showed that the novel level measurement system is able to detect levels of sand and liquid as well as clean water/oil interface levels with very high accuracy. Flow had no significant influence on the measurement results and the sensor output remained stable over the cause of one month. After the successful testing, the system has been qualified for its first trial on an offshore installation. In addition to an offshore pilot, more R&D needs to be conducted in order to develop capabilities to measure emulsion and foam interface layers as well as to determine how fouling by scale, waxes and other impurities present in a full-scale separator influence the measurement.
A Mathematical Model and Numerical Simulation of Waterflood Induced Dynamic Fractures of Low Permeability Reservoirs
Du, Kai (China University of Petroleum, Beijing) | Rui, Zhenhua (China University of Petroleum, Beijing) | Dindoruk, Birol (University of Houston) | Yang, Tao (Equinor) | Patil, Shirish (King Fahd University of Petroleum & Minerals)
Abstract As a powerful technique for reservoir simulation, the embedded discrete fracture model (EDFM) has been widely used for unconventional fracture reservoirs. However, the appearance of dynamic fractures caused by fracture extension during well stimulation brings significant challenge to reservoir simulation. We presented a new numerical method to model the dynamic fracture performance for horizontal wells in unconventional reservoirs by using EDFM in this study. The proposed method includes a numerical model and a workflow to simulate water-oil flow in an unconventional fracture reservoir. The fracture dynamics are not only considered into the pressure-dependent properties of fractures (such as fracture permeability, porosity), but also incorporated into EDFM by activating or deactivating grid blocks of fractures at each time step. Fracturing treatment data during stimulation and microseismic data after hydraulic fracturing provide a quantitative understanding of the dynamic fracture behaviors, including fracture location and geometries with time. We conducted a comparative analysis with respect to static fracture properties and dynamic fracture properties. In comparison to static fractures, dynamic fractures have a substantially higher bottomhole pressure. We also analyzed how production was impacted by shut-in time and water injection rate. Different production systems have varying cumulative oil and water production, and an optimal production system was identified. The quantitative understanding of fracture dynamics for field application examples helps to achieve more accurate production estimation.
- Energy > Oil & Gas > Upstream (1.00)
- Water & Waste Management > Water Management > Lifecycle > Disposal/Injection (0.74)
- Asia > China > Shanxi > Ordos Basin (0.99)
- Asia > China > Shaanxi > Ordos Basin (0.99)
- Asia > China > Gansu > Ordos Basin (0.99)
DeepStar Innovative Technology Development & Deployment Outlook
Shamshy, S. (Chevron) | Lee, C. (CPC Corporation) | Joseph, J. (Equinor) | Sun, W. (ExxonMobil) | Gayneaux, J. (Hess) | Sakurai, T. (INPEX) | Gomes, J. (Offshore Operators Committee) | Thompson, C. (Oxy) | Lima, C. (Petrobras) | Patni, S. (Shell) | Mateen, K. (TotalEnergies)
Executive Summary To meet the growing dual energy challenges of meeting growing demand for energy while reducing greenhouse gas emissions, it is crucial that the energy industry, including oil and gas companies, engineering firms, manufacturers, suppliers, regulators, energy-related academic institutes, and research organizations can collaboratively develop new technologies together to unlock offshore especially deepwater resources in safe and efficient manners. This DeepStar presentation will discuss the key challenges and technology development outlook that the industry can collaborate with. Leading collaborative examples of the DeepStar Program will be shared to understand how industry pioneers work together to reduce the cost and risks of developing novel technologies. By leveraging collective wisdom in areas absent of competitive advantages and unlocking collaborative capabilities between technology providers and commercial operated assets, DeepStar provides a unique platform whereby the joint industry needs of offshore deepwater energy producers can be addressed in a cost- and time-efficient manner. In order to address these needs, Deepstar has access to venture and research funding from various resources to unlock deepwater offshore energy potential that would otherwise be stranded due to technological limitations. What is "normal today" was "impossible 10 years ago"; what is "impossible today" will be normal 10 years from now. In offshore development, in 1878, the world's first modern oil tanker was built; in 1949, the first offshore mobile drilling platform was built; in 1977, the first FPSO was manufactured; in 1991, the first guideline-less subsea tree was available; in 2003, first semi-submersible facility in Gulf Of Mexico; in 2011, drilling water depth exceeded 3,000 meters; in 2015, the first subsea gas compression was put in operations; in 2018, the first autonomous offshore robot came in action, this groundbreaking development revolutionized the way operations are conducted in the offshore environment, opening up new possibilities and transforming the industry's approach to safety, efficiency, and cost-effectiveness. DeepStar is a global offshore technology development consortium founded in 1991. Its current members include 10 energy operators (Chevron, CPC, Equinor, ExxonMobil, Hess, INPEX, Oxy, Petrobras, Shell, and TotalEnergies) as members, and 30 plus tech service companies, research institutes as associate members that provide technical solutions to energy operators and industry. Utilizing its increasing image and significant leverage, DeepStar is to collaboratively deliver the most needed innovative technologies, including in engineering optimization, standardization, offshore drilling and interventions, reservoir monitoring, long-distance tie-back, advanced risers, all electrics, subsea separation, subsea boosting, autonomous subsea, autonomous FPSO, offshore wind, offshore carbon capture/decarbonization, for the energy industry. The key success of the DeepStar program is to let industry partners collaboratively work together to efficiently develop innovative technologies via significant leverage and cost savings to improve offshore operations. The program fosters collaboration among various stakeholders in the energy industry, including energy operators, tech service companies, and research institutes. This collaborative approach enables the pooling of resources, knowledge, and expertise, leading to the development of innovative technologies that address key challenges in offshore and deepwater operations. By bringing together industry pioneers, DeepStar harnesses collective wisdom and leverages funds to reduce costs and risks associated with technology development and increase the industry voice for solving common problems. DeepStar has several technical subcommittees which cover the key areas such as field development including drilling & completions, reservoir, facilities, autonomous operations, greenhouse gas emission and carbon abatement, flow assurance, subsea, etc. These subcommittees work together to identify the industry's key challenges and develop innovative technologies needed. DeepStar also promotes the adoption of innovative technologies through various initiatives, including conferences, workshops, and publications. Five technologies developed in DeepStar will be highlighted, which include 1) Hibot Robotic System, 2) Baker Hughes Veros Sensors Systems, 3) Baker Hughes REACH™ wireline-retrievable safety valve 4) Damorphe - Daido Steel - Baker Hughes Salinity Insensitive Metallic Barrier Assembly (SIMBA) with Smart Dissolvable Plugged Nozzle Assemblies (DPNAs), and 5) Damorphe-NaganoKeiki: High-Pressure High-Temperature (HPHT) - Flowable Sensor Ball. The selection of these five technologies in the DeepStar program was based on several criteria. Firstly, these technologies were chosen based on their relevance to the industry's current needs and challenges. They address critical areas such as engineering optimization, offshore drilling, reservoir monitoring, subsea operations, and autonomous systems. The selection also considers the maturity of the technologies, ensuring that they have reached a stage where they can be effectively deployed and commercially available and completed field deployed. Additionally, the technologies have demonstrated significant potential for cost reduction, risk mitigation, safety improvements, and environmental considerations, making them prime candidates for development and adoption within the industry.
- North America > United States (0.88)
- Asia > Middle East > UAE (0.28)
- North America > United States > Gulf of Mexico > Central GOM > West Gulf Coast Tertiary Basin > Walker Ridge > Block 628 > Julia Field (0.99)
- North America > United States > Gulf of Mexico > Central GOM > West Gulf Coast Tertiary Basin > Walker Ridge > Block 627 > Julia Field (0.99)
- North America > United States > Gulf of Mexico > Central GOM > West Gulf Coast Tertiary Basin > Walker Ridge > Block 584 > Julia Field (0.99)
- (2 more...)
The Evolution of UDAR Technologies for Risk Mitigation in Geostopping Applications
Sinha, Supriya (Equinor) | Antonsen, Frank (Equinor) | Clegg, Nigel (Halliburton) | Walmsley, Arthur (Halliburton) | Vicuña, Brígido (Halliburton) | Danielsen, Berit Ensted (Equinor) | Constable, Monica Vik (Equinor) | Prymak-Moyle, Marta (Equinor)
Abstract Complications during drilling and completion operations caused by subsurface geology have a significant impact on rig time, cost, assets, and even human life, if risk and incident severity is not well understood. Risk and tolerance evaluation processes are essential for completing successful drilling programs and final casing designs. While log-based correlation methodologies can be used, they are limited to scenarios where appropriate offset well data control exists, and they only provide information after the hole has been drilled. The development of technologies that provide warning of a hazardous zone before it is penetrated are therefore desirable. Ultradeep Azimuthal Resistivity (UDAR) tools are deployed for such scenarios and provide high value when used in integrated interpretations to identify hazards ahead of drill bit. Seismic data is used as a first step to predict and map subsurface characteristics such as pressure regimes, faults, and fluid contacts. Offset and pilot hole data further complements assessment of these features enabling more precise risk assessment. Commonly, near-bit measurements such as resistivity and gamma ray have been used for these correlations in conjunction with sonic and density measurements. The mapping of horizons from seismic data can have 10s to 100s of meters of vertical uncertainty, while offset data in exploration campaigns is typically sparse and near-bit measurements require drilling into the zone of risk. Pilot holes therefore become a costly necessity, however, if sufficient resistivity contrast exists UDAR can be used for remote boundary mapping, without drilling into the geohazards, thus reducing cost and de-risking the operation. This paper presents several case studies where UDAR technology was deployed in near vertical to horizontal wells to map geohazards before they were penetrated using different techniques, allowing optimization of the stopping point in diverse scenarios. This includes a case where the technology was used to geostop in a horizontal section prior to penetration of a major structural sealing fault plane that bounded the productive reservoir interval. UDAR has been successfully used to manage seismic uncertainty, support the decision-making process for core point selection, reduce exposure of unstable overburden shales and geostop above abnormal and subnormal pressure zones. Mapping a geohazard and proactively stopping at a particular depth is a complex operation and evaluation of the rock properties with respect to the sensitivity of the measurements and uncertainty in the models is important. Limitations in measurement sensitivity can lead to potential masking of top reservoir picks and increased uncertainty in both boundary positions and the inverted resistivity. Improvements such as new UDAR transmitter designs being embedded into Rotary Steerable Systems allow near-bit placement of this technology, demonstrating the continual evolution of this technology and how it assists risk mitigation in geostopping applications.
- North America (1.00)
- Asia (0.93)
- Europe > United Kingdom (0.67)
- Geology > Structural Geology > Fault (0.68)
- Geology > Geological Subdiscipline > Geomechanics (0.48)
- Geology > Geological Subdiscipline > Stratigraphy (0.46)
Semi-Automated Rock Classification for Permeability Estimation Using High-Resolution Computed Tomography Scan Images, Core Photos, and Well Logs
Gonzalez, Andres (Hildebrand Department of Petroleum and Geosystems Engineering, The University of Texas at Austin) | Sahu, Pallavi (Hildebrand Department of Petroleum and Geosystems Engineering, The University of Texas at Austin) | Heidari, Zoya (Hildebrand Department of Petroleum and Geosystems Engineering, The University of Texas at Austin (Corresponding author)) | Lopez, Olivier (Equinor)
Summary Reliable estimation of petrophysical properties can be challenging, especially in geological formations with rapid variation in the spatial distribution of rock components. The spatial distribution of rock components, also known as rock fabric, is often not captured by conventional well logs that are typically used for the estimation of petrophysical properties. The aforementioned challenge is rooted in the limited vertical resolution of conventional well logging tools. Alternatively, specialized tools and techniques, such as nuclear magnetic resonance (NMR) and computed tomography (CT) scan images, can provide information on the variation in the rock fabric of geological formations. The objectives of this paper are (a) to use 2D CT scan images and core photos, conventional well logs, NMR logs, and core-measured properties for semi-automated rock classification, (b) to develop class-based rock physics models for enhanced petrophysical properties estimation, and (c) to provide a method to expedite the detection of quantitative image-based rock classes in cored wells. First, we conducted conventional formation evaluation (CFE) for the initial assessment of petrophysical properties. Then, we implemented three different rock classification techniques for class-based estimation of petrophysical properties. The first of the rock classification techniques uses routine core analysis (RCA) data to define hydraulic units. The second rock classification technique uses NMR data to characterize the changes in pore-size distribution of the evaluated formation. The last rock classification technique integrates quantitative image-based features from CT scan images and core photos with NMR data. Finally, the obtained rock classes from the abovementioned rock classification techniques are used to derive class-based permeability models. We applied the proposed workflow to a pilot well drilled in a saline water aquifer formation that will be used for CO2 injection and storage in the Northern Lights carbon capture and storage (CCS) project. The extracted image-based rock fabric features were in agreement with the visual aspect of the evaluated depth intervals. The detected rock classes captured the fluid-flow behavior using a permeability-based cost function in two of the implemented rock classification techniques, the variation in petrophysical and compositional properties through well logs, and quantitative rock fabric of the evaluated depth interval through the core image data. Finally, the use of class-based rock physics models improved permeability estimates, decreasing the mean relative error by up to 37% compared with formation-based permeability estimates from a conventional method (formation-based porosity-permeability correlations). One of the key contributions of the proposed workflow is that it integrates conventional well logs, core-measured properties, NMR logs, and high-resolution image data. As a result, the obtained integrated rock classes capture key petrophysical and geological parameters of the evaluated depth intervals that are typically not included in rock classification efforts. The obtained integrated rock classes can potentially improve the development of accurate geological models, which are used in simulation efforts as a screening tool for the selection of geological formations for CO2 storage as well as for storage capacity, selection of CO2 injection intervals, and containment forecasting.
- Geology > Geological Subdiscipline > Geomechanics (0.54)
- Geology > Rock Type > Sedimentary Rock (0.46)
- North America > United States > Texas > Permian Basin > Midland Basin (0.99)
- North America > United States > Texas > Haynesville Shale Formation (0.99)
- North America > United States > Louisiana > Haynesville Shale Formation (0.99)
- (2 more...)
UNDERSTANDING THE SYNERGISTIC IMPACT OF STRESS RELEASE AND CEMENTATION ON SANDSTONE USING SOUND WAVES - IMPLICATIONS FOR EXHUMATION ESTIMATION
Yu, Jiaxin (Norwegian University of Science and Technology) | Duffaut, Kenneth (Equinor) | Avseth, Per (Dig Science, Norwegian University of Science and Technology)
Exhumation is the process that encompasses both uplift and erosion, leading to the removal of overburden and the release of effective stress exerted on rocks. When estimating exhumation magnitude using the compaction trend method, it is commonly assumed that the physical properties of rocks are insensitive to stress reduction. However, recent laboratory evidence has shown that porosity exhibits weaker sensitivity to stress release compared to velocity that can be significantly affected by stress release. This raises uncertainties regarding the assumption of irreversible compaction. It remains unclear whether the impact of stress release can be observed in real rocks in exhumed areas, as there is a lack of methods to directly measure the impact of stress release on field data. Additionally, studying real rocks is further complicated by the presence of rock diagenesis and its interaction with stress release. To address these knowledge gaps, this study employs stress-dependent burial and uplift modeling and interprets an extensive well log dataset using the modeling-derived evaluation metrics. We discover that the disparity between porosity sensitivity and velocity sensitivity to stress release can be leveraged to derive a metric porosity inconsistency which can serve as both a qualitative and quantitative measure for identifying and evaluating stress release in sandstone using geophysical field measurements. We have gathered a significant amount of sonic velocity and porosity data from normally compacted and uplifted clean sandstones in the Norwegian Sea and the Barents Sea. Notably, we observe significant porosity inconsistency in the exhumed well 6510/2-1 in the Norwegian Sea. In the Barents Sea, well data reveals a varying pattern of porosity inconsistency that not only aligns with the spatial variation of exhumation reported in various studies but also exhibits a positive correlation with the magnitude of exhumation. These observations provide support for the predictions made by the conceptual modeling.
- Europe > Norway > Norwegian Sea (0.68)
- Europe > United Kingdom (0.67)
- Phanerozoic > Cenozoic (0.93)
- Phanerozoic > Mesozoic > Jurassic (0.92)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Sandstone (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (0.47)
- Geophysics > Seismic Surveying > Seismic Modeling > Velocity Modeling (0.93)
- Geophysics > Borehole Geophysics (0.66)
- Oceania > Australia > Western Australia > Perth Basin (0.99)
- Oceania > Australia > Victoria > Otway Basin (0.99)
- Oceania > Australia > South Australia > Otway Basin (0.99)
- (13 more...)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Reservoir geomechanics (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Geologic modeling (1.00)
- (3 more...)
ABSTRACT Quantitative description of the reservoir rock stress sensitivity is critical for seismic modeling and interpretation. Laboratory studies have indicated that the wave velocity of high porosity cemented sandstone is asymmetrically much more sensitive to stress unloading than stress loading. However, there is a lack of a simple rock physics model that is capable of describing the asymmetric stress sensitivity of reservoir rock. A new rock physics model is developed by extending an existing rock physics model based on contact theory combined with elastic bounds. The new model relates the stress softening of rock to cement cracking and crumbling induced by stress release. The diluting factor is introduced to describe the weakening of effective cement and analyze the increase of stress sensitivity when the stress is gradually removed. The combination of the new model and its base model forms a rock physics modeling workflow that can accurately describe the evolution of velocities measured in samples undergoing stress loading and unloading. The model performance is compared with samples representing synthetic weakly cemented glass bead pack and sandstone manufactured with different cements at different forming stress levels. The modeling results are in accordance with the measured stress sensitivities of wave velocities. The sequential model calibration using a simple constraint optimization approach yields important calibration parameters that are indicative of the elastic stress sensitivity and damage behavior in the studied rocks. The model can be particularly interesting for time-lapse monitoring of fluid injection and seismic interpretation of overpressured reservoir rock.
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Sandstone (0.99)
- Geophysics > Seismic Surveying > Seismic Interpretation (0.66)
- Geophysics > Seismic Surveying > Seismic Modeling (0.48)
- Oceania > Australia > South Australia > Cooper Basin (0.99)
- Oceania > Australia > Queensland > Cooper Basin (0.99)
- Europe > Norway > North Sea > Northern North Sea > East Shetland Basin > License 120 > Block 34/8 > Visund Field > Ststfjord Formation (0.99)
- (4 more...)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Reservoir geomechanics (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Exploration, development, structural geology (1.00)
ABSTRACT Polyester ropes change length after experiencing high loads in operation. In benign waters, mooring systems with polyester ropes have been used to a large extent, where the length change has not been reported to be an issue or has been handled by mooring line length adjustment. When moving to harsh environment installations, length change becomes a potential issue, both for offset and mooring system performance. The length changes in a polyester rope taut mooring system in operation in harsh environment has been studied, and the findings with respect to both elongation, contraction and stiffness are presented in this paper. INTRODUCTION Polyester ropes have been used for many years in long term mooring of offshore installations, typically in deep waters with taut mooring lines. A particular challenge has been the increase in line length, referred to as permanent stretch, following higher tensions than previously experienced by the polyester ropes. As these mooring lines tend to be very long (typically 2000-3000 m), even the smallest change in length (in percent) can make a significant impact on the total line length. If not actively adjusted during operation, this will affect the mean tension in the mooring system, which is an important parameter for both extreme line tension and offset during storm events. For long term mooring with taut mooring lines in deep waters, the permanent stretch has typically been handled by either (i) tensioning the ropes to the highest possible load during or just after installation, (ii) designing the mooring system to allow for increased line length, (iii) use winches to pull in the ropes after elongation, or (iv) a combination of these strategies. This has worked well, especially as many of the polyester rope mooring systems have not been in very harsh environment areas, and/or have been equipped with winches enabling line length adjustments after peak loads leading to an elongation of the ropes. For mooring systems on installations not able to adjust length in operation, predicting the final length of the ropes can be challenging. This now becomes an issue for turret moored FPSOs in deep water (taut mooring) and harsh environment, and for floating wind turbines with hybrid semi-taut mooring systems in shallow water. Understanding the change-in-length becomes vital for design of the mooring systems, and experience from taut systems in benign environment may not be covering the upcoming applications.
Summary The Assisted Cement Log Interpretation Project has used machine learning (ML) to create a tool that interprets cement logs by predicting a predefined set of annular condition codes used in the cement log interpretation process. The development of a cement log interpretation tool speeds up the log interpretation process and enables expert knowledge to be efficiently shared when training new professionals. By using high-quality and consistent training data sets, the project has trained a model that will support unbiased and consistent interpretations over time. The tool consists of a training and a prediction tool integrated with cased-hole logging interpretation software. By containerizing the code using an “API First” design principle (API: application programming interface), the applicability of this add-on tool is broad. The ML model is trained using selected and engineered features from cement logs, and the tool predicts an annular condition code according to the cement classification system for each depth segment in the log. The interpreters can easily fetch a complete cement log interpretation prediction for the log and use that as a template for their final interpretation. The ML model can easily be retrained with new data sets to improve accuracy even further. To improve cement log interpretation consistency in the industry, the code will be made available as open source.
- Europe (0.68)
- Asia > Middle East (0.67)
- North America > United States > Texas (0.46)