Modeling accurate lithofacies and petrophysical properties is a crucial step in the reservoir characterization as it affects reservoir heterogeneity, fluid flow modeling, and history matching, especially in complex geological structures. In this paper, the multiple-point facies geostatistics (MPFG) and sequential gaussian simulation were integrated as an efficient workflow for lithofacies and petrophysical property modeling of a fluvial sand-rich depositional environment of Zubair formation in South Rumaila oil field, Southern Iraq. The lithofacies features of the upper sandstone member has three main lithotypes derived from the core data analysis of 20 wells: sand, shaly sand, and shale.
In the MPFG, the surface map of the fluvial depositional system of the upper sandstone reservoir in Zubair formation was created through a 2D user-defined training image. The training image body and channels were pointed to the three aforementioned lithofacies as an alternative to the variogram to create the 3D facies system. Then, the surface map was sampled and trained by neural networks to create the discrete template of 3D facies distribution pattern into the 3D grid construction. The resulted pattern represents a numerical geomodel that captures all the features of the fluvial depositional environment of the reservoir, which then was adopted for 3D lithofacies modeling.
The resulting MPFG-lithofacies model reflected a more reasonable facies architecture than the sequential indicator simulation by preserving the fluvial features of the geosystem. Many realizations were generated and cross-validated to determine the most appropriate lithofacies model, which was considered later for the permeability and porosity modeling by the sequential gaussian simulation. To attain history matching, the resulting MPFG and petrophysical model was upscaled and incorporated into the compositional reservoir flow simulation for history matching. A near-perfect and fast history matching with the least mismatch was obtained with respect to observed and calculated cumulative and rates of oil production and water injection for the entire field in addition to all producers and injectors within the whole production history. The results reflect how is efficient considering multiple-point statistics to reconstruct the complex geological features to capture reservoir heterogeneity and achieve fast history matching.
This paper examines the effects of ocean currents on the vortex-induced vibration response of deepwater tubulars, such as umbilicals, production risers, tendons, and drilling risers, in proximity. This issue has received very little attention by the industry yet potentially has substantial importance to the design of deepwater tubulars and platforms.
Experiments have been conducted in a current flume on tandem flexible tubulars with diameter ratios of 2:1 and 4:1. The smaller diameter tubular was placed in both the upstream and downstream positions, with the top and bottom locations spaced apart at three different distances. The tension was kept constant, but the current speed was varied. While both uniform flow and sheared flow tests were conducted, only the uniform flow tests are reported herein.
The response modes varied from about 1-6, so that they were sufficiently high to easily allow both single mode and multiple mode responses, of which both were prevalent throughout the testing program. While all of the tests were conducted at low Reynolds numbers, the results can be thoughtfully translated to most field applications.
The results describe the vibration and response characteristics of both the upstream and downstream tubulars for various configurations that were tested. Since a myriad of diameter ratios, separation distances, and flow velocities are possible with tubulars in the field, these tests have attempted to provide general insights into the responses of tandem tubulars with unequal diameters and, in some cases, offer guidance on limitations to the responses that can be used for offshore field designs.
Digital well planning, construction and maintenance have a lot of potential for cost reduction and improved HSE. Developing a software model to replace many of the tasks performed by humans can reduce administrative tasks and enables more focus on the quality of plans and operations. One single model to overlook engineering and activity through the life cycle of wells from the planning phase, through construction, production, maintenance to the final plugging unlocks many potential improvements. One possible feature for a Life Cycle Well Integrity Model (LCWIM) is to embed industry standards to supply guidance and recommendations during the life cycle of a well. Changing the format of standards so both computers and humans understand their content can benefit the planning and operational phases of well construction, intervention, production and finally plugging.
Typically, standards are used broadly in the planning phase. However, in the later phases of the life cycle of the well, it is often more difficult to accommodate both changes in operations and updates to industry standards. Embedding the industry "best practice" into software for planning well construction and maintenance, can prevent potential human errors and ensure an appropriate well construction. Having standards as "digital eye" on the engineering and well construction parameters can help to ensure safer operation and help to ensure that no regulations are overseen due to human error.
Standards can be considered a collection of experiences gathered over decades in the industry, and they represent the common ground for description of methods and procedures for safe and sustainable operations. When digital well planning gradually replaces the traditional manual planning processes, the vast experience of standards can support engineers more actively and directly compared to text documents. This paper describes an approach to merge the digital version of a standard into the LCWIM so it actively provides relevant information to ongoing operations similar to a help function. The user would experience this as "relevant information" by just a mouse-click. The method of choice elaborated in this article shows a life cycle standard in the shape of an active support module to the LCWIM. The reasons behind the selected approach is twofold: (1) LCWIM is a life cycle tool, which incorporates life cycle standards to support all activities in all phases, (2) Standards support LCWIM by verifying that tests and procedures are in compliance.
The focus of this paper is to demonstrate how a life cycle standard like the NORSOK D-10 Rev. 4, June 2013 can be completely digitalized to take an active part in planning and operations. The scope is limited to section 5.6 "Casing design" with elaboration of section 5.6.3 "Load cases" to stepwise show one way the standard can become interactive.
The HPHT Metal-to-Metal Annulus Seal Assembly provides an all metal gas tight seal for the annulus between the 18 3/4″ wellhead housing and in-wellhead casing hangers. The seal is weight set with running string weight to achieve a low-pressure seal, then energized and locked using the running tool by applying pressure below the BOP. It locks directly to the casing hanger via the casing hanger lock ring while the wellhead housing lock ring secures the seal assembly and casing hanger to the wellhead housing. Both lock rings provide a verification that the casing hanger and seal assembly are installed correctly. The seal is run in a single trip with the casing hanger, and if the seal fails to set, it is automatically retrieved with the running tool, leaving the casing hanger installed; the seal can then be re-run on a separate tool.
The seal is API 17TR8 compliant and qualified to 20,000 psi bore pressure and 15,000 psi annulus pressure from 0°F to 350°F. It is also fit for sour service as it is made from NACE MR0175 compliant materials.
This design is based on the field-proven technology of an existing Metal-to-Metal Annulus Seal Assembly. The design process involved detailed elastic-plastic finite element analysis and a FMECA-driven qualification approach involving a crossfunctional team consisting of experienced personnel. The FMECA was essential in developing the Metal-to-Metal Annulus Seal Assembly by defining necessary additional testing beyond that required by the industry or customers.
The following qualification tests were successfully completed on two independent annulus seal assemblies (proving repeatability):
Seal #1: PR2 per API Specification 6A, 20th Ed., Annex F, Subclause F.2.23: 20,000 psi bore x 11,000 psi annulus, 0°F-350°F Ambient temperature hydrostatic extended cycle testing per API Specification 17D, 2nd Ed., Subclause 5.1.7: 200 × 20,000 psi bore pressure cycles, 200 × 11,000 psi annulus pressure cycles
PR2 per API Specification 6A, 20th Ed., Annex F, Subclause F.2.23: 20,000 psi bore x 11,000 psi annulus, 0°F-350°F
Ambient temperature hydrostatic extended cycle testing per API Specification 17D, 2nd Ed., Subclause 5.1.7: 200 × 20,000 psi bore pressure cycles, 200 × 11,000 psi annulus pressure cycles
Seal #2: Worst case discharge simulation: 20,000 psi bore × 11,000 psi annulus, 0°F-350°F PR2 per API Specification 6A, 20th Ed., Annex F, Subclause F.2.23: 20,000 psi bore × 15,000 psi annulus, 0°F-350°F Ambient temperature hydrostatic extended cycle testing per API Specification 17D, 2nd Ed., Subclause 5.1.7: 200 × 20,000 psi bore pressure cycles, 200 × 15,000 psi annulus pressure cycles
Worst case discharge simulation: 20,000 psi bore × 11,000 psi annulus, 0°F-350°F
PR2 per API Specification 6A, 20th Ed., Annex F, Subclause F.2.23: 20,000 psi bore × 15,000 psi annulus, 0°F-350°F
Ambient temperature hydrostatic extended cycle testing per API Specification 17D, 2nd Ed., Subclause 5.1.7: 200 × 20,000 psi bore pressure cycles, 200 × 15,000 psi annulus pressure cycles
This paper presents the application of a reliability based design methodology for interference between trawl gear and pipelines, and the associated cost savings in subsea rock installation.
As part of Wintershall Norge's Maria development project, a 26 km long 14″ production flowline with DEH (Direct Electrical Heating) and a 46 km (43 km + 3 km infield) long 12″ water injection pipeline has been installed and left exposed on the seabed. The seabed topography in the area is un-even and scarred by iceberg ploughmarks, leading to a significant number of large free spans. Furthermore, fishing activity must be taken into account in the design of these pipelines. According to DNV-RP-F111, if the trawl gear hits in a free span, the pull-over load will be significantly higher than if it hits a section in contact with the seabed.
Preliminary analysis indicated that by using the LRFD (Load and Resistance Factor Design) approach as per DNV-RP-F111, a large number of free spans would require rock infill in order to limit the trawl pull-over load. In order to optimize the design and potentially reduce the requirement for free span infill, an optimised methodology based on SRA (Structural Reliability Analysis) was proposed by Wintershall, developed by DNV GL and implemented by Subsea 7 during detail design phase.
The optimised methodology involves FE analyses of the sensitivity to various parameters and Monte Carlo simulations, in order to quantitatively assess the probability of failure. Specific FE models analysing the bending moment capacity and response were established. The various input parameters were assessed and included as distributions if deemed required from the sensitivity analysis. Finally, a Monte Carlo simulation was performed to calculate the probability of failure.
It was demonstrated that the target safety levels defined by DNV-OS-F101 were reached without free span infill, and hence significant savings in subsea rock installation could be achieved without any deviation from the DNV-OS-F101 code. Cost saving due to reduced subsea rock installation scope is estimated to 7.6 mill Euro. Wintershall facilitated a close dialogue between DNV GL and Subsea 7 throughout the work progress. This resulted in a constructive and open approach, ensuring efficient delivery of the detailed design in line with project schedule.
The work carried out has demonstrated two relevant examples where performing a SRA, as opposed to a LRFD, has resulted in a significant reduction of seabed intervention requirements and an associated cost saving, while still being in compliance with DNV-OS-F101 target safety levels. To our knowledge this is the first time the SRA method has been applied for trawl interference design on a live project, and on a CRA (Corrosion Resistant Alloy) lined pipeline with DEH system attached. The success was made possible by close collaboration between the parties involved; Wintershall, DNV GL and Subsea 7.
Mounir, N. (Advantek Waste Management Services) | Guo, Y. (Advantek Waste Management Services) | Panchal, Y. (Advantek Waste Management Services) | Mohamed, I. M. (Advantek Waste Management Services) | Abou-Sayed, A. (Advantek Waste Management Services) | Abou-Sayed, O. (Advantek Waste Management Services)
The E&P industry is rich in all types of data. Without proper database and analytics, companies are not able to retrieve and analyze the data they need in an efficient way. The result of the data management problems is that decisions are often made using incomplete or incorrect information. Even when the desired data is accessible, requirements for gathering and formatting it may limit the amount of analysis performed before a timely decision must be made.
Strong data management is required to transform wells-related data into an integrated system of information. The key to successful data management is in the use of sophisticated platform-independent codes that doesn't need any special setup or systems which allows easy transfer of information and data over the internet. This paper describes the data management and accompanying analytics approach taken in support of operations in Egypt to provide a shared knowledge system.
This innovative cloud application provides a common interface to multiple systems in the organization, allowing a richer and more complete source of data to be used for decision making. Moreover, it enables the integration of static data, such as well logs in a particular region, with a real-time system to facilitate integrative real-time analyses using artificial intelligence, cloud-hosted physics-based simulators, or both.
To support deepwater needs such as those in Egypt, the system incorporates productivity optimization analysis, reservoir geomechanics (pore pressure prediction, log interpretation, reservoir collapse, fault activation, subsidence, compaction, etc.), and data mining of key development uncertainty and well performance drivers.
The Parque das Conchas (BC10) field offshore Brazil, operated by Shell and owned together with ONGC and QPI, has challenging reservoir conditions. Several subsea fields with viscosities ranging from 1 to 900 cP and gas volume fractions between 5% and 70% require subsea boosting to lift production fluids to the FPSO facility. Since first oil in 2009, a unique method of subsea separation and boosting has been deployed on BC-10, utilizing vertical caisson separators with Electrical Submersible Pumps (ESP's) to pump well fluids from up to 2000m water depth to the FPSO facility. Maintenance of the ESP assemblies requires an intervention using a MODU (Mobile Offshore Drilling Unit).
Shell pursued an alternative subsea boosting solution using Mudline Pump (MLP) technology, with the objective to reduce field Opex and increase redundancy. The MLP was conceived as a retrofit module, which was to be fully compatible with the existing infrastructure. This includes using existing variable frequency drives, high voltage umbilicals, subsea mechanical interfaces, controls, hydraulics, and chemical injection. Despite the prior development of a 3 MW (megawatt) MudLine Pump (MK1), the specifics of the BC10 application required further development and qualification. The design pressure was increased from 5,000 psi to 7,500 psi, which required requalification of motor and barrier fluid circuit components. Additionally, the challenging multiphase flow conditions led to the development of an innovative control strategy to maximise the production window, whilst ensuring safe operating conditions for the pump within the existing system constraints.
The O&G industry and renewables industry are integrating more and more through the use of energy conversion systems to cut costs. This paper describes the testing and applications of a renewable generated power source.
Müller, D. T. (Petrobras) | Nogueira, D. C. (Petrobras) | Gonzalez, E. C. (Petrobras) | Nicolosi, E R. (Petrobras) | Dutra, E. S. S. (Petrobras) | Campello, G. C. (Petrobras) | Muniz, T. J. C. (Petrobras) | Capella, M. M. (Petrobras)
The integrity management of Campos Basin platforms, subsea systems and wells and its risks control due to ageing process are key priorities for HSE. With this awareness, Petrobras is implementing initiatives to improve the production viability of mature fields and to extend the life of current facilities.
This paper will describe some of these initiatives, which include: carrying out platforms maintenance campaigns using UMS (Units for Maintenance and Safety); subsea facilities and platforms life extension studies; well integrity evaluations; compliance with the new regulatory aspects of ANP (Brazilian National Petroleum, Gas and Biofuels Agency); development of business decision-making methodology based on break-even point; implementation of decommissioning projects of non-operating structures that have reached their technical and economic limit. As an example, it will be presented the extension of the concession contracts for the Marlim and Voador fields until 2052, which were originally due to expire in 2025.
The design of a long gas flowline laid on a rough seabed and in which HP/HT gas is circulating shows that the numerous spans along the line were all acceptable and that some acceptable lateral buckles will occur at some key features (crests).
A long section of the line was expected to be anchored preventing any walking. A first analysis with the steepest P/T transients showed no walking behaviour of the line. However it was observed that, when the line is gradually heated to the highest HT/HP profiles, unacceptable walking is observed at hot end. This paper will present how this line was designed and how an effective mitigation design was performed to prevent unacceptable walking and how that was implemented at the appropriate time in the overall design process.
Design activities were performed with non-linear finite-element software able to model the pipeline and its interaction with the rough seabed. The standard design activities were done, specifically; on-bottom roughness, lateral buckling analyses and their conclusions combined at the end of the design process into a global model built to simulate potential interaction between buckles and spans. This is a stepped process that should be followed in any pipeline design activities.
All spans and all potential rogue buckles were found acceptable, and the steepest HP/HT transients did not induce walking behaviour, as per conclusions from preliminary engineering studies. However, combining the most severe HP/HT scenario (corresponding to restart of the wells one after another) found spans along the line and the most probable scenario for locations of buckles led to unacceptable walking at hot end. This phenomenon is explained by the interaction between buckles and spans, as they evolve with the applied loadings. Mitigating this walking was achieved by integrating a padeye in the end structure. This particular padeye was linked by a chain to a single suction pile installed nearby. The integration of the mitigating padeye was done without any interruption to the overall schedule. This was achieved by an effective design process which listed the Key Interface Datas (KIDs) which in turn defines the important milestones between engineering disciplines (pipeline, structure, installation, fabrication).
There is no one single scenario that can lead to pipeline walking, particularly for lines laid on rough seabed with many spans and buckles. It is recommended to always study a case where several cycles of maximum operational profiles are applied. The overall design process should also list the Key Interface Datas in the overall schedule in order to ease the interfaces between engineering disciplines.