Melilo Junior, Angelo Celio (Petrobras) | Oliveira da Costa, Carlos Henrique (Petrobras) | Armani Delalibera, Carlos Alberto (Petrobras) | Schwingel Dias, Marco Antônio (Petrobras) | Palmeira de Oliveira, Thomaz Murrieta (Petrobras) | Pereira, Rafael Merenda (Petrobras)
The Libra Extend Well Test (EWT) project is composed of 2 satellite wells interconnected to an FPSO with an external Turret anchor. One well is the producer, with 6-inch service lines and 8-inch production line in lazy wave risers configuration. The other well is the injector, with two 6-inch gas flow lines also in lazy wave compliant configuration. In the project planning several actions were considered in order to guarantee the first oil date determined by the project, while the production unit (FPSO) was not available in the location and ready to pull-in campaign. One of these actions studied and later adopted was the prelaying operation of the flexible lines with floaters in the lazy wave configuration of the production line of the production well. Later on, similar studies were done considering the pre-laying of injection lines also. As this type of operation is not a track records at Petrobras for the ultra-deep water scenario, additional studies were necessary to ensure its feasibility and the safety execution. The objective of this article is to present the previous studies and the result achieved in the pre-laying operation of flexible line with floaters in the lazy wave configuration of the Libra EWT service line.
After years of development, qualification and engineering, subsea compression technology is now a proven solution to increase the recovery factor for offshore gas developments. The first subsea compression system was installed at the Aasgard field in the Norwegian Sea, which was started up successfully on the 17th. of September 2015. This project represents an important milestone for the oil and gas industry, as apart from representing the successful developments of new subsea processing technologies, subsea compression also proves itself a viable alternative field development option to oil and gas operators.
The experience from Aasgard enables tomorrow’s subsea compression solutions. The basis is increased field recovery by subsea compression. In addition it opens for wells stream and deep water applications, as well as CO2 EOR.
This paper aims to share Aker Solutions’ experience on Aasgard Subsea Compression project, from the design and the project execution phases up to the operational phase, highlighting the key learnings from more than 50 000 hours of successful subsea operation.
In addition, the paper will also describe the ongoing development activities to optimize the compression system delivered for Aasgard, with particular focus on increased field recovery and unit size and weight optimization without requiring qualification activities of new technologies. This new generation of subsea compression system will extend the applicability of this technology to a much wider range of fields and offshore regions.
Hazarika, Simanta (Oil & Natural Gas Corporation Ltd) | Rathod, P. Ramulu (Oil & Natural Gas Corporation Ltd) | Burla, Ravishankar (Oil & Natural Gas Corporation Ltd) | Das, Gour Chandra (Oil & Natural Gas Corporation Ltd) | Rao, Bkvrl (Oil & Natural Gas Corporation Ltd) | Deuri, Budhin (Oil & Natural Gas Corporation Ltd)
Subsea flow lines in deep water are typically exposed to high pressure and low temperature conditions which can create problems due to formation of gas hydrate. The gas hydrate formed can plug the flow lines causing not only loss of production, but may also create severe safety and environmental hazard. Moreover, dissociation of these plugs may take weeks or even months. Assessment of the hydrate formation potential during both steady is therefore an essential part of field development studies.
The paper presents a case study of a gas field located in KG basin of India which was brought on production in 2018. The objective of the study was to assist the on-site team on issues related to hydrate inhibition during ongoing initial start-up operation and assess the arrival time of rich MEG in the onshore plant in view of turn down flow conditions during commissioning.
The study also demonstrates how the transient simulations helped to monitor progress, identify and respond quickly to address the challenges during initial start-up operation of the deepwater gas field in Indian east coast. It emphasizes the need for accurate estimation of rich MEG arrival time and the minimum required gas flow rate from the subsea wells to ensure timely return of rich MEG to the onshore plant in order to avoid disruption in hydrate inhibition in the subsea system.
The innovations of marine LNG terminal concepts are a hot area of research for several years. In order to study the towing and sinking hydrodynamic properties of the large-scale concrete LNG terminals, the basin test and numerical simulation was carried out to simulate the dynamic motion of the concrete LNG terminals towed to the site and sinking on the seabed.
When the caission is placed, the caission generates motion under the action of the waves, and the caission is restrained by the control cable during the movement. Based on the stability and safety considerations of caission sinking construction under the marine environment conditions, it is necessary to know the motion state of the entire sinking process of caission. Therefore, it is necessary to numerically predict the motion response of caission.
The force anlysis of the caission structure in water is a viscous wave-making problem a bluff body in a restricted area. In the viscous medium with infinite domain, the flow around the object can only be solved satisfactorily when the Reynolds number is small. The caisson involves not only the blunt body but also the large Reynolds number of the medium and the influence of restricted boundary and free surface. Therefore, it is generally believed that the most reliable method is experimental research. As the caisson section is square and blunt, the flow separation point is stable, which creates conditions for self-similarity in experimental study. Therefore, in theory, the experimental study can obtain quite satisfactory results. The main purpose of the towing tests is to investigate the dynamic behavior and characteristics of the caisson and the line tensions during towing out from the dry dock to the sea area in waves and currents.
Related work on towing of Large-scale structure. Kyozuka, Y.
The ‘Pseudo’ Dry Gas (PDG) subsea concept is being developed to dramatically improve the efficiency of subsea gas transportation by removing fluids at the earliest point of accumulation. The technology will increase the geographical reach from receiving gas terminals, allowing asset owners to prolong production life without the need for more expensive design solutions. This paper will provide an overview of the innovative technology, demonstrating that a 200 km plus tie back can be achieved, without compression.
Increasing the distance of subsea tie-backs increases the liquid inventory, with constraints on pipeline diameter for slug free flow. The PDG concept is based on a main gas line integrated with piggable gravity powered drain liquid removal unit and pumps (a smaller fluid line transports separated liquid). Multiple units are specified to drain liquids as they condense in the line, maintaining near dry service. Liquid free operation removes the constraint on pipeline diameter. Specification of a large diameter pipe (within installation limits) reduces backpressure on the wells, enhancing recovery. Minimum stable flow limits are removed, improving tail end recovery.
Current stranded gas development options (subsea compression, floating facilities, FLNG) generate a step change in costs which can make a project uneconomic. This is even more acute in mature and semi-mature basins where existing gas processing facilities / LNG terminals already exist offshore or onshore along with sunk costs from the exploration. A case study for a 185 km pseudo dry gas subsea tie-back to shore demonstrates the PDG concept feasibility. This result is used to argue that the PDG concept should be included in the suite of subsea processing options considered by Operators in early field development planning.
The pipeline inspection is one of the most critical tasks in the oil and gas industries. The operation of a remotely operated vehicle (ROV) for the pipeline inspection is very costly since it requires both a human operator and the support vessel to which an ROV must be tethered. Furthermore, this tether also limits the surveillance ability of an ROV. Thus, the use of autonomous underwater vehicles (AUVs) can greatly reduce the operation cost of pipeline inspection since an AUV can freely and automatically navigate without tethering to support vessel. In order for an AUV to navigate automatically under the limited vision in the underwater environment, the forward-looking sonar (FLS) is the essential part since the quality of images captured by an optical camera degrade significantly by the turbid water and the low-light condition whereas images produced from an acoustic sonar As a result, in this work, we are interested in the use of a 2-D multi-beam Forward-Looking Sonar (FLS) to capture echo images on a frontal vision since acoustic signals can pass through tiny particles in turbid medium water . This deployment ensures that an image of pipelines can be captured regardless of low underwater visibility conditions. Other types of sonars that are regularly used in underwater visual inspection include the side scan sonar (SSS), synthetic aperture sonar (SAS), and multi-beam echo sounder (MBES). There are a limited number of works that focus on the pipeline detection problem. An optical camera was employed in  for visual feedback and heading control, SSS and MBES were used in ,  and  for pipeline tracking, and, in , FLS was used for linear object detection and tracking.
Ng, Sok Mooi (PETRONAS Carigali Sdn. Bhd.) | Khan, Riaz (PETRONAS Carigali Sdn. Bhd.) | Isnadi, Biramarta (PETRONAS Carigali Sdn. Bhd.) | Lee, Luong Ann (PETRONAS Carigali Sdn. Bhd.) | Saminal, Siti Nurshamshinazzatulbalqis (PETRONAS Carigali Sdn. Bhd.)
The objective of this paper is to share the holistic approach to managing aging fleet for offshore fixed steel structures. PETRONAS is currently operating a fleet of more than 200 fixed offshore structures in Malaysian water. More than half of it has exceeded the original design life. With enhanced oil recovery and other developing technologies, offshore platforms often than not are required to continue operating beyond its original design life.
A holistic approach for life extension of fixed offshore structures are being developed to ensure safe operations of the facilities. PETRONAS has started SIM journey since 2007. The approach of Data, Evaluation, Strategy and Programme in line with API RP 2SIM set the basis for managing the integrity of the offshore fleet. An integrated solution was developed to manage both topsides and substructures. The Structural Integrity Compliance System (SICS) which houses the integrity management of topsides deteriorations to prioritize resources through risk based anomalies management. Risk based underwater inspection also formed part of the solutions, addressing mainly extreme storm in the region. Other Major Accidental Hazards (MAHs) risk ranking included in SICS are vessel collision and seismic. Management of facilities with minimal redundancy such as guyed wire monopod is addressed through time based inspection. A regional hazard curve is also developed to ensure the facilities are meeting the acceptance criteria set forth by the industry.
Besides aging, other integrity triggers including shallow gas and subsidence required a different scheme in managing the integrity of the facilities, primarily addressed through a comprehensive monitoring programme.
There is no one size fit all recipe in managing the aged platforms for life extension. The data plays a crucial role in ensuring the right methodology is deployed in support of digitalization and data driven decision making. Implementation of the system is proven to be reliable in ensuring the offshore fixed structures are intact to support safe and continuous operations to the operator in a cost optimum manner. The data analytics help to enhance the predictive model to optimize the inspection and maintenance programme.
Strong ownership and commitment of the structural integrity engineers in ensuring the data integrity maintain the challenge in sustainability of the system and provide reliable source for data driven decision making to the operator.
Category: Operational Excellence (136 - Managing Aging Facilities)
This paper will discuss further on the recent decommissioning project of fields which has been completed on November 2017. These two platforms had been totally removed and became an artificial reef at Sarawak water in Malaysia. This paper will show the activities and best practices; the team had gone through from early stage until completion of the process based on the decommissioning phases. The decommissioning framework consists of five phases starting from Late Life Planning and Preparation; Regulatory, Compliance and Permitting; Facilities Hook-down and wells make safe; Removal and Remediation and lastly, Post Remediation. In baseline inspection, the underwater inspection had provided some information to the contractor on the scope and revealed some of the uncertainties about the decommissioning project. On an important note, an engineering study is critical to ensure safe operation. After our observation, we noted that actual operation is similar to the engineering's simulation where the team had to follow the engineering accordingly. Reefing engineering crucially needed to be performed to ensure the facilities been placed at the right location and position. During offshore execution removal of facilities, there were challenges we faced such as malfunction of the cutting/dredge equipment which led to a back up plan and innovative solution. We had to utilize other available equipments available onboard (Diamond wire cutter, abrasive waterjet internal cutter, dredger, soil plug removal, airlift, cutting torch etc.). Selection of cutting tools also needed to be considered to minimize the pinch effect of the facilities. Finally, Post decommissioning survey had been carried during the Post Remediation phase to assess the successful of the project. The post-decommissioning/reefing survey had been carried out and the result observed new marine growth and numbers of fishes at the reefed platform. It had been concluded that this decommissioning reefing project was successful. This paper should be an interest to those who will be exploring abandonment and decommissioning project which includes reefing as one of the decommissioning options. This paper will also show on decommissioning process through Engineering, Preparation, Removal and Disposal (EPRD) approach contract. The novelty in this paper is on the assurance that had been made by Company via baseline and post reefing survey to ensure environment aspect had been considered.
Development of marginal deep water fields requires an integrated and cost-effective approach for costs minimization and production enhancement by synergies with existing surrounding infrastructures. This paper details the successful use of Integrated Reservoir and Production Modelling to unlock the development of three marginal deep water oil discoveries in synergy with an existing surrounding subsea development. A marginal field is usually defined as a field that may not produce enough net income to make it worth developing. Deep water satellites are among those, requiring important development optimizations to unlock their potential. Integrated Reservoir and Production Modelling is largely used within the Oil and Gas industry for evaluating production forecasts associated to development assumptions by modeling the fluid flow from pore to process while honoring all required subsurface to surface constraints. This paper describes how the use of such modeling approach has been used to unlock the development of these marginal oil discoveries by evaluating the value of different development concepts from stand-alone to tie-back together with standardized and under-qualification subsea technologies. The Integrated Reservoir and Production Models were made of the three reservoir dynamic models of the three marginal fields connected to the well and network production models capturing the various concepts evaluated. Three main development concepts have been tested: stand-alone, short tie-back to field X and long tie-back to field Y. For all these concepts, many sensitivities have been performed: well implementation patterns, well completion and activation, production and injection networks design including subsea boosting and surface capacities debottlenecking. Tie-back to field X has then been further evaluated to determine detailed bases of design maximizing the value of the project. Integrated Reservoir and Production Modelling has been key to enable cross-functional team work and determine the best incremental value of these marginal fields in synergy with the production of the surrounding existing field.
The oil and gas industry will continue to play an essential role in meeting the growing world energy demand for decades to come. A fact sometimes overlooked is that the industry is also a major consumer of energy and a contributor to Greenhouse Gas (GHG) emissions. In recent years, there has been increasing interest in the use of renewable energy in the oil industry. Various technologies are used to produce renewable energy, from solar radiation to harnessing the power of the wind and sea. The application of different types of renewable energy in oil and gas fields is reviewed. The advantages and limitations of each technology are discussed. This paper presents the state of the art on current and potential applications of the different technologies of renewable energy in the oil and gas industry. The paper demonstrates that using renewables offer many advantages including saving hydrocarbon resources, minimizing the oil industry's GHG emission and enhancing its public image.