An international Energy Company & independent engineering company have performed preliminary studies for an In-Line Robot (ILR) Project including: feasibility study, turbine design (with CFD calculations and flow assurance) and Energy Balance Assessments. This Robot will be a tetherless autonomous device capable of travelling with/against production flow to accomplish pigging and inspection missions inside pipelines with minimum production impacts. This is particularly adapted for single line long tiebacks, thanks to regenerative power management but the complexity of subsea architecture, flow conditions & fluids services raises some challenges. The ILR development is programmed over five phases (Feasibility study, Preliminary Systems design & Energy Balance Assessment, Flow Loop Bench Testing, Prototype Testing and Commercialisation). Phase 2 utilised Computational Fluid Dynamics (CFD) simulation models to assess power extraction levels from production flow across various scenarios whilst minimising pressure drop. The results obtained included the turbine CFD models that were coupled to power conversion and storage modules in order to ensure that system drive and power managementwere captured in a closed loop. An operational envelope was established considering the preliminary turbine design simulations as well as the associated energy balance. This paper will present the results to date along with the key design features of the ILR and how the data will be used to verify the operational envelope during the next phase, Flow Loop Bench Testing which is due to start in late 2019. This will provide data to configure and predict operational envelopes of the robot for different flow patterns and fluid types.
Saudi Aramco studied such algorithms to produce images simulating the flow inside a pipe’s cross section, possibly reducing the need for separator-based multiphase flowmeters. A former technical manager with Petrobras discusses the development of the company’s flow assurance philosophies and strategies. Looped lines are used to reduce pressure drop and increase flow capacity, but information on the flow behavior or predictive methods are not available for these systems. Bypass pigging has advantages over conventional approaches. Its application to multi-phase flow with high wax content crude is discussed.
Completion comes despite two cyclones disrupting the project area during installation, McDermott said. At the 2016 Gulf of Mexico Deepwater Technical Symposium in New Orleans, a presentation discussed the application of sensors and analytics in pipeline integrity management systems. An experimental study was conducted by use of a 6-in.-inner-diameter Use of unmanned aerial vehicles to monitor pipeline networks for theft and other issues is discussed. Bypass pigging has advantages over conventional approaches.
Pipeline pigs are devices that are placed inside the pipe and traverse the pipeline. Pigs may be used in hydrostatic testing and pipeline drying, internal cleaning, internal coating, liquid management, batching, and inspection. Figure 1 shows several types of pipeline pigs. The pig is inserted ahead of the fill point, and water is pumped behind the pig to keep the pipe full of water and force air out ahead of the pig. Pigs are then used to remove the test waters and to dry the pipeline.
When waxy oil is transported through a pipeline and the pipeline operating temperature drops below the waxappearance temperature (WAT), the wax will precipitate and eventually deposit onto the pipeline's interior surface if a temperature gradient between the bulk fluid and the pipe wall exists. However, because of various operational factors, routine pigging might be delayed for an extended period, thus allowing the wax deposit to accumulate. When this occurs, progressive pigging is required to gradually remove the wax accumulation. Typically, it starts by launching a bore-finding pig (BFP), as shown in Figure 1, followed by pigs with progressively increasing diameters until the routine pig can be fully resumed. An example of a series of progressive pigs and an example of an intermediate cleaning (IC) pig are shown in Figs. 2 and 3, respectively.
Li, Weidong (China Universiyu of Petroleum, Beijing) | Huang, Qiyu (China Universiyu of Petroleum, Beijing) | Wang, Wenda (China Huanqiu Contracting & Engineering Co., Ltd.) | Ren, Yijie (China University of Petroleum, Beijing) | Dong, Xue (China University of Petroleum, Beijing) | Zhao, Qi (China University of Petroleum, Beijing) | Hou, Lei (China University of Petroleum, Beijing)
Widely used as it is, pipeline pigging still holds ambiguities in its mechanisms. In this paper we explore the nature of the wax removal process with a unique pigging facility. Solid wax content, yield stress, viscoelasticity, and microscopic characteristics of wax samples are thoroughly studied with differential-scanning-calorimetry (DSC) trials, rheological tests, and microscopic observations. We found that the relative solid wax content is approximately linearly dependent on temperature, and yield stress can be well-fitted with wax content in an exponential format. An investigation on wax-breaking force indicates that it increases with solid wax content. Wax removal efficiency increases with wax thickness and pipe-wall temperature, decreases with a wax-mixing ratio and solid wax content, and it varies irregularly vs. the scraping-element hardness in the pig. Furthermore, a prediction model of wax removal efficiency was developed on the basis of nondimensional analysis. The absolute average deviation of verification experiments against this model is 5.22%. This model might benefit in estimating the wax-scouring capacity of the wax-in-oil slurry and, therefore, helps to avoid wax blockage and to arrange the pigging program.
Pipeline inline inspection requires a proper cleaning of the pipeline inner walls. In the case hereby described of a 30km 12" offshore line, a significant amount of wax deposits was expected and a series hydromechanical cleaning tools were deployed, after a preliminary series of less aggressive pigs. Normally, the progress of the cleaning process is monitored only by the arrival conditions of the cleaning tools and of the receiving trap. To improve the process, miniaturized pressure, temperature and acceleration sensors were added to the cleaning tools, directly in the field, without any modifications to the cleaning devices and without introducing any additional risks or operating impact. After each instrumented cleaning tool, the sensor data were quickly analyzed and led to the selection of most suitable subsequent tool. In this way, it was observed that the pig conditions and the amount of material collected in the receiving trap did not fully indicate the true cleaning status of the pipeline, while the sensors provided a clearer picture. The pig sequence was thus optimized in number and type of pigs and the intelligent pig run was preformed successfully with no issues or data loss. The advantage of these tiny sensors, not foreseen in the hydro-mechanical pig design, is that they can be applied to almost any pig with minimal-to-no modifications. This information can be used in a number of ways, including detection of flow restrictions (dents, deposits), and can also be used to recreate the line elevation, profile with limited a priori information.
It is well understood that deposits such as corrosion and scale can greatly reduce the flow efficiency and throughput of a transport pipeline system. Regular intervention activities to promote flow assurance such as frequent mechanical pigging, introduction of chemical corrosion inhibitors, and introduction of drag reducing agents all require consistent operational expense, or significant pipeline downtime. Use of interior pipeline coatings and liners are potential long-term solutions which would represent a way to provide long-term refurbishment benefits.
This work describes a novel material designed to interact specifically with highly corroded and weathered pipe, enabling in-place application and refurbishment. The material is applied extremely thinly on the pipeline interior, such that it might be considered a surface treatment, yet it is designed for permanence and for strong adhesion to even severely corroded surfaces. This water-and-oil compatible, chemically resistant material shows extreme resistance to corrosion, particle abrasion and delamination under operational conditions, and is specifically designed to reduce surface roughness by several orders of magnitude. By reducing surface roughness, losses due to frictional drag can be minimized, together with the chance of forming deposits of iron scale and black powder that can constrict pipeline flow and overall production.
A case study is presented in this work which describes application of the coating to a fluid transport system, including a variety of different "challenge" features including: 90° 1.5D bends, valves, weld seams, flanged connections, and heavily corroded surfaces. The pipeline systems were all treated via an in-situ methodology and evaluated for flow performance both through modeling and experimental observation. The study of the practical effects of utilizing a low surface energy, low surface roughness coating that can be effectively applied to severely corroded pipelines with a minimum of surface preparation demonstrates how new material breakthroughs can allow for revitalization of previously mature intervention techniques.
Kollamgunta, Saikiran (National Petroleum Construction Company) | G. V. R. A., Srinivasa Rao (National Petroleum Construction Company) | Singh, Harendra (National Petroleum Construction Company) | Kamal, Faris Ragheb (National Petroleum Construction Company) | Takieddine, Oussama (National Petroleum Construction Company)
One of the major challenges in the upstream oil and gas industry is de-bottlenecking of existing slug catcher/ inlet separator system during facilities up-gradation or due to changes in production rates for any other reasons. It is often found that upgrades or changes result in increased slug volume from the upstream pipelines thus making existing slug catcher or separators inadequate to handle the increased load. Even in cases of normal pigging not involving debottlenecking of existing facilities, production rates are required to be lowered. This is done as excess liquid slugs generated due to pigging may show severe operational problems in terms of level and pressure fluctuations in a separator leading to poor separation, potential liquid flooding, increased flaring, emergency shutdown and production loss. The use of by-pass pigs can effectively reduce the liquid arrival rate at the slug catcher over conventional approach by delivering a more uniformly mixed fluid even at relatively higher production rates. It thereby reduces the slug volume and hence, the requirement of increased surge capacity. Further, in brownfield applications, it enables optimal use of existing assets or avoiding new slug catcher.
Operators are reluctant to reduce the production flow rate to very low value for pigging, as this normally results in reduction in revenue. Bypass pigging, as compared with conventional pigging, is able to reduce the pig velocity even at relatively higher production rates. It, however, requires careful evaluation and design as in many cases, such as well fluid having wax, solids or high asphaltenes may result in blockage of the bypass holes thus impacting the effectiveness of the operation. Transient modeling and simulation of bypass pigging using OLGA Dynamic Multiphase Flow Simulator has been performed to address such issues.
This paper describes the strategies to address de-bottlenecking challenges due to increased surge volumes to be accommodated in the existing slug catcher/ separator system and use of by-pass pigging to overcome these. The application of the technique used i.e. bypass pigging is demonstrated by transient multiphase simulation using OLGA dynamic simulator. Proposed design solutions are based on NPCC's extensive and successful experience in tackling challenging Brownfield projects.
National Oilwell Varco (NOV) announced the commercial availability of its subsea automated pig launcher (SAPL) system. The SAPL is designed to reduce the development costs of subsea tiebacks in wax-prone fields and to remove slug in gas-transportation lines, potentially eliminating the need for a second production line, or loop system, in such scenarios. The SAPL system, which is mounted on a subsea structure and loaded with pigs from a retrievable cassette, enables operational pigging without vessel or remotely operated vehicle support, reducing typical deployment and retrieval costs when compared with conventional subsea pig launchers. The cassette can house several pigs, which can be launched from shore or a platform at a desired time. The SAPL is designed to simplify precommissioning and commissioning operations as well as wax- and slug-control operations.