Prelude Floating Liquefied Natural Gas (FLNG) facility reached a significant milestone in June 2018 when gas was introduced onboard for the first time as part of the facility start-up process, loaded from an LNG carri...
详细信息
ISBN:
(纸本)9780791884317
Prelude Floating Liquefied Natural Gas (FLNG) facility reached a significant milestone in June 2018 when gas was introduced onboard for the first time as part of the facility start-up process, loaded from an LNG carrier moored in side-by-side (SBS) configuration. This first offshore LNG SBS operation allowed Prelude's utilities to switch from running on diesel to running on gas. SBS mooring is the base case configuration for offloading both LNG and Liquefied Petroleum Gas (LPG) into product carriers using Marine Loading Arms (MLA) once the Prelude FLNG facility is fully operational. These complex and weather sensitive operations are expected to take place on a weekly basis. This means critical decisions about weather-window and timing should be supported as much as possible by predictive analysis and modelling of environment forecasts to reduce the risks. Prelude Floating Liquefied Natural Gas (FLNG) is designed to offload Liquefied Natural Gas (LNG) and Liquefied Petroleum Gas (LPG) to carrier vessels moored in a side-by-side (SBS) configuration, using Marine Loading Arms (MLA) technology. For onshore terminals or small/medium FLNG, the traditional design of MLA (Double Counterweight Marine Arm - DCMA), featuring a vertical riser, can be used. However due to the exceptional freeboard of Prelude a new type of MLA was designed, namely the Offshore Loading Arm Footless (OLAF), without vertical riser in order to reach the LNG or LPG manifolds located as far as about 16 meters below the MLA base. Thanks to the OLAF design, the length and weight of the articulated MLA sections is reduced in comparison with conventional DCMA, and so are the dynamic loads applied by the MLA on the vessel manifold, which was mandatory to remain below the acceptable stress limit of standard LNG/LPG carrier manifolds. OLAF employs the field proven targeting system (TS) allowing the connection and disconnection of the MLA to the vessel manifold in dynamic conditions. This paper describes the a
Estimation of environmental and complex structural responses, such as fatigue for risers on deepwater floating production systems, is a critical and generally computationally intensive process. Long term damage estima...
详细信息
ISBN:
(纸本)9781510824294
Estimation of environmental and complex structural responses, such as fatigue for risers on deepwater floating production systems, is a critical and generally computationally intensive process. Long term damage estimates require the determination of host vessel motions used for riser stress calculations. In principle, riser stress could be calculated for each of a large number of directional sea states, a considerable computational burden. However, it might be possible to identify a representative subset of directional sea states for vessel motion and subsequent riser stress analysis, such that estimated fatigue characteristics (from the full set of sea states and the subset thereof) were equivalent. This would be advantageous as it would require considerably less computational effort. In this work we use non hierarchical K-MEANS cluster analysis to partition a large set of directional wave spectra for contiguous sea states at a location offshore Brazil, corresponding to a period of approximately 2 years into a number of clusters. We adopt the set comprised of cluster centroids only as representative sea states for efficient characterization of the environment and structural response. We demonstrate that the representative sea states provide an efficient basis for estimation of overall sea state bulk, wind sea and swell characteristics. We evaluate the effect of cluster size on the performance of the representative sea states using custom built visualization tools utilizing the Kolmogorov-Smirnov test statistics. The representative sea states are further used as input for a VLCC-class FPSO vessel motion analysis. For heave at the turret, roll motions, and relative vessel heading, distributions of vessel motions from analysis of representative sea states are in excellent agreement with those from analysis of all sea states. Guidelines for the application of the methodology are provided. Copyright 2016, Offshore technology Conference.
Centrifugal compressors are considered one of the most critical components in oil industry, making the minimization of their downtime and the maximization of their availability a major target. Maintenance is thought t...
详细信息
ISBN:
(纸本)9781509027798
Centrifugal compressors are considered one of the most critical components in oil industry, making the minimization of their downtime and the maximization of their availability a major target. Maintenance is thought to be a key aspect towards achieving this goal, leading to various maintenance schemes being proposed over the years. Condition based maintenance and prognostics and health management (CBM/PHM), which is relying on the concepts of diagnostics and prognostics, has been gaining ground over the last years due to its ability of being able to plan the maintenance schedule in advance. The successful application of this policy is heavily dependent on the quality of data used and a major issue affecting it, is that of missing data. Missing data's presence may compromise the information contained within a set, thus having a significant effect on the conclusions that can be drawn from the data, as there might be bias or misleading results. Consequently, it is important to address this matter. A number of methodologies to recover the data, called imputation techniques, have been proposed. This paper reviews the most widely used techniques and presents a case study with the use of actual industrial centrifugal compressor data, in order to identify the most suitable ones.
This paper summarizes the laboratory and simulation studies conducted to evaluate the potential of low-salinity polymer flood for the Gao-30 reservoir in Huabei Oilfield, China which has a high reservoir temperature o...
详细信息
ISBN:
(纸本)9781510803527
This paper summarizes the laboratory and simulation studies conducted to evaluate the potential of low-salinity polymer flood for the Gao-30 reservoir in Huabei Oilfield, China which has a high reservoir temperature of 113°C, moderate formation salinity of 9,000 ppm total dissolved solids and in-situ oil viscosity of 25 cP. Our studies have identified GL-100, a specially designed rigid structure modified polyacrylamide, as a polymer candidate for the Gao-30 reservoir because it exhibits adequate thermal stability and acceptable injectivity. Laboratory results show that for GL-100, low-salinity brine has the dual benefits of improved thermal stability and higher viscosity compared to formation brine. Spontaneous imbibition experiments using Gao-30 core plugs show that secondary mode imbibition by softened formation brine recovers more oil than imbibition by formation brine. In addition, significant incremental oil recovery was observed with injection of low-salinity polymer into a heterogeneous Gao-30 core, compared with formation water flooding. Corefloods in secondary mode were conducted with low-salinity and formation brines. Results were history matched to obtain the relative permeability and capillary pressure curves. These results and laboratory measured polymer rheology and adsorption were used as input into reservoir simulations to forecast benefits of low-salinity polymer flood in two pilot locations chosen from full field history matching of 20 years of waterflood in the Gao-30 reservoir. Reservoir simulations were run to compare the incremental oil recovery resulting from injection of various slug sizes of formation-salinity polymer and low-salinity polymer. Our simulations only considered the increase in viscosity due to polymer and the improvement of thermal stability of polymer in low-salinity brine. Low-salinity chemical effects through changes in the relative permeability curves were not included. Results show that injection of 0.3 PV formation-salini
The Majnoon Field was discovered in 1976 and brought online in 2002 by the Iraq South Oil Company (SOC). In December 2009, during the Ministry of Oil's 2nd Petroleum Licensing Round, shell won the right to develop...
详细信息
ISBN:
(纸本)9781634398053
The Majnoon Field was discovered in 1976 and brought online in 2002 by the Iraq South Oil Company (SOC). In December 2009, during the Ministry of Oil's 2nd Petroleum Licensing Round, shell won the right to develop the field under a Development and Production Services Contract. shell Iraq Petroleum Development BV (SIPD) became operator for the Majnoon Field (45%), with partners Petronas Carigali (30%) and Missan Oil Company (25%). In September 2013, first oil from the combination of newly built and the refurbished existing facilities & wells, was established. In accordance with the terms of the contract, a minimum average flow rate of 175k bpd over a period of 90 days was achieved in order to meet the First Commercial Production (FCP) target and thus allow shell to begin cost recovery. This paper will be based on shell's experience executing the Majnoon field development in South Iraq. The project scope was completed in challenging circumstances, with very little subsurface information available to confirm design assumptions. As a result, a number of execution risks were transferred to the commissioning & initial start-up operations. The team ultimately relied on experience, planned contingencies and intelligent workarounds to achieve the FCP production target. The key startup challenges will be discussed in this paper that are relevant to the audience, particularly those involved in field start-up & operations. Conclusions will relate to how the team overcame flow instabilities (slugging) from daisy chained pipelines (linking the multiple wellpads), crude foaming in the process facilities, welding debris in the flare system, dealing with export curtailment (process stops and re-starts) and establishing custody transfer measurement with SOC. In addition, this paper will present a selected number of Majnoon lessons learned during the commissioning & startup period and how shell improves Project Delivery in subsequent projects to achieve Flawless Startups to meet the o
The precipitating carbonate process utilizes the carbonate to bicarbonate reaction for the absorption of CO 2 followed by precipitation and concentration of part of the bicarbonate before entering the regenerator. Thi...
详细信息
The precipitating carbonate process utilizes the carbonate to bicarbonate reaction for the absorption of CO 2 followed by precipitation and concentration of part of the bicarbonate before entering the regenerator. This process can be an attractive alternative for existing carbon-capture post-combustion technologies because of its energy efficiency potential. Screening pilot plant experiments of the precipitating carbonate process have shown sufficiently high cyclic loadings and confirmed the operation at the predicted low stripping steam rates. The CO 2 vapour pressure of lean solvent entering the absorber was low enough to supply sufficient driving force for 90% removal of CO 2 from flue gas containing 4% CO 2 . This needs to be further demonstrated in a further improved pilot-plant set-up.
暂无评论