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Due to the progressive exploitation of natural gas fields pipeline designers facing more and more challenging demands to ensure durable and safe operation conditions for their products. Besides a reliable application in arctic areas, in the deep sea or in seismically active regions the HIC resistance for H2S containing fluids is a key requirement which has to be fulfilled. Here, sophisticated pipe material and tailormade solutions for specific projects have to be developed.
Over the last decades EUROPIPE is looking back on a successful history in the delivery of sour service material based on TMCP plates. This paper gives an overview about EUROPIPE´s development activities and the contribution in actual pipeline projects to fortify the confidence in the use of TMCP material:
In the beginning adequate steel making practices for sour service material are presented. Afterwards the requirements for sour service steels and the benefits of TM rolling with accelerated cooling are introduced. Furthermore it is explained how the design concerning material grades and corrosion testing has developed in the past. An outlook on further developments will be given as well.
During a controlled TM rolling process the precipitation stages, grain refinement and microstructure of line pipe material can be adjusted to meet requirements which are needed for later operation. Accelerated cooling ensures a homogeneous material and restricts carbon redistribution and banded microstructures. These effects lead to a reduction of HIC and SSC initiation sites due to inhomogeneity. Nevertheless recent operator experience has questioned the general suitability of TMCP rolled products for sour service. From the pipe manufacturers position lean alloy designs below material grade X60 are considered unsuitable due to the resulting heavy wall thicknesses and the higher deformation rates in processing plates to pipe. On the other hand the developments towards even higher grades are influenced by discussions concerning an increased carbon content and local hard spots. The presented information will show that the use of grade X65 is technically justified and the recent research activities towards the implementation of higher grades shall be further considered and developed.
Due to given results pipeline operators and manufacturers are encouraged to maintain their fruitful cooperation in the development of high quality-products even for application under severe sour service conditions.
Floating LNG (FLNG) technologies are being deployed to monetize mid-sized offshore gas reservoirs, avoiding constructing a sub-sea gas pipeline to a land based LNG facility and export jetty. A previous OTC-Brasil paper (OTC-26158 Gas Pretreatment Considerations for Floating LNG) has discussed marinization and pre-treatment options available for FLNG, and an OTC paper (OTC-27940 Liquefaction Technologies and Mechanical Drive Considerations for Floating LNG) has discussed space, weight, and safety consideration in liquefaction technology selection. This paper is a continuation, focusing on the thermodynamic and efficiency considerations of the liquefaction technology options. For those not familiar with the previous work, there is some discussion of the marinization and safety drivers within the focus topic. Offshore liquefaction technologies are often novel and many lack offshore references. The available offshore liquefaction technologies will be presented by Licensor and Technology name. Because of the diversity of liquefaction technologies, and to remain Licensor agnostic, the technologies are grouped by refrigeration method, with Nitrogen expander and SMR (Single Mixed Refrigerant) groupings of technologies examined with an emphasis on overall liquefaction efficiency, efficiency focus areas and design flexibility. DMR (Dual Mixed Refrigerant) is compared with the other two technology groupings. The paper provides an overview of the FLNG state of the art in liquefaction.
In this work a nonlinear model predictive controller (NMPC) applied to an offshore petroleum production facility is presented. The facility was simulated using Hysys dynamic simulation, and the used NMPC controller with phenomenological mathematical model was the BRNMPC. Some comparisons were conducted regarding the use of NMPC, linear MPC and traditional PID controllers. The results showed that for level control of the separator vessels, the MPC and NMPC have similar performance, but for pressure vessel control, the NMPC are superior because the system has more nonlinearities and many information were lost in the linearization process.
This paper highlights the challenges to drilling risers and running equipment for offshore drilling operations from dynamically positioned mobile offshore drilling units (MODUs) in extreme water depths. Whereas nearly all exploratory drilling has occurred in water depths shallower than 3,000-m, Total recently set the water depth record with its Raya-1 well (3,400-m water depth, offshore Uruguay) using the Maersk Valiant drillship. Petrobras has also set a new Brazilian record for exploratory drilling by reaching a water depth of nearly 3,000-m. The 3-BRSA-1296-SES well was drilled to a water depth of 2,988-m the Moita Bonita area, located in the Sergipe Alagoas basin off northeastern Brazil. Several operators have leases that extend into significantly deeper water depths. This paper discusses approaches and criteria to evaluate the suitability these systems for operations in such depths. As drilling water depths increase, candidate MODUs may require additional and/or upgraded subsea and running equipment to perform drilling operations.
The purpose of this work is to present the development of low-manganese pipes containing 1% Cr and Boron manufactured by the HF-ERW process according to standard
The chemical composition of the steel was designed in such a way to ensure good weldability, high hardenability and low mechanical properties variation after tempering. Low levels of Manganese was established and increase the resistance of hydrogen induced cracking due the tendency of formation of MnS inclusions in the continuous casting. Additionally, levels of 1%Cr were incorporated to ensure corrosion resistance in water injection wells. Hollomon model was used to set the tempering temperature as a function of the aim mechanical property. To characterize the tube, the follow tests were performed, tensile, Charpy, hardness, microhardness, optical microscopy, SEM and CO2 corrosion tests.
The seam weld presented excellent results under UT inspection. The low variability in the mechanical properties shows that the quench and tempering process was stable, which is able to meet the
In view of the results we conclude that the low manganese tube containing 1%Cr manufactured by the process HF-ERW meets the requirements of Standard
Saad, H. C. (National Agency of Petroleum, Natural Gas and Biofuels) | Bergamaschi, M. B. (National Agency of Petroleum, Natural Gas and Biofuels) | Tavares, G. R. (Universidade Federal Fluminense) | Santos, M. D. (Universidade Federal Fluminense)
This paper aims to discuss the role of the National Agency of Petroleum, Natural Gas and Biofuels (ANP) in the inspection of fluid measurements, and to present a history of improvement of the issuance of infraction notices, related to the violation of the current resolutions, in addition to their sanctioning implications to regulated agents. In order to carry out this study, the data of all infraction notices issued by the Nucleus of Insspection of Measurement of Petroleum and Natural Gas Production (NFP) from 2010 to 2015 were analyzed, showing the process of finding nonconformities on the measurement systems and how infraction's amount is calculated. In addition, the results of court judgments will be present and, finally, a comparison between the number of infraction notice issued, the infraction committed and the punitive pedagogical implications applied. Futhermore after a critical analysus of each infraction notice issued and its respective nonconmities, it is observed that the most common infraction is the divergence between the values declared in the Daily Production Report and those recorded in the flow computer of the measurement system monitored by NFP. These and other infraction notices generate financial penalties whose are set to force operators to follow the recommendation given by ANP.
As drilling muds evolve to satisfy well requirements, cementing preflush technologies need to change to ensure proper mud removal during cementing jobs. A new component—engineering-designed fiber—was added to a preflush fluid and tested in the laboratory, with promising results. The system was then implemented in Latin America.
Obtaining proper mud removal is very important for achieving zonal isolation at cementing jobs. The new technology consists of the addition of an engineering-designed fiber to cementing preflush fluids to significantly improve the removal of nonaqueous fluids from the well during cementing operations. The fibers are compatible with both cement slurries and mud. They work by removing the mud from the casing or formation through two mechanisms: by mechanical cleaning and by attracting the nonaqueous compound of the mud toward itself by hydrophobic-hydrophobic interaction. Two different methodologies were used to evaluate the fiber's ability to enhance the chemical wash and spacer capabilities to clean and demulsificate the nonaqueous mud fluids.
The laboratory tests were performed with cementing preflush fluids with and without the fibers. Results indicated that the preflushes with the fibers were able to clean and demulsificate the drilling mud much more efficiently than preflush without the fibers. Indeed, it was possible to optimize the amount of the preflush surfactants and still obtain excellent results. Some successful cases of field implementation of this technology corroborated the laboratory findings. In both cementing jobs, results indicated very efficient mud removal, and, consequently, zonal isolation and well integrity were achieved.
The fibers were successfully pumped in a field in Latin America. This innovative technology is able to enhance cement bonding in both casing and formation and reduces potential remedial job costs in a wide range of challenging environments.
Control system failures in subsea operations are a leading cause of Blowout Preventer (BOP) down-time. The cost of these failures can increase exponentially with water depth. Legacy BOP control systems are based on 90-year-old hydraulics technology and have been stretched to cope with new regulatory requirements and harsher environments. The industry has responded to these design requirements by increasing component sizes, weights, and system complexities. These adaptations have resulted in unintended consequences, such as reduced reliability and an increase in wellhead loading. As subsea operations move into deeper water and wellhead pressures increase above 15,000 psi, legacy control systems may have reached their design limit. This paper introduces a new concept of an all-electric BOP, a game-changing technology that will not only negate these issues, but also improve the safety, efficiency, reliability, and functionality of subsea BOP control systems.
The objective of this research was to study the formation of water-in-oil microdispersions due to crude oil-brine interactions as a novel mechanism that improves oil recovery with low salinity waterflooding in carbonate formations. This novel interpretation was studied by intergrating petrographic and spectroscopic observations, dynamic interfacial tension measurements, thermogravimetrical analyses and core flooding techniques.
To address this interpretation, this study examines crude oil-brine interactions and the compositional changes that occur in the crude oil when it is in contact with brines of various concentration. Three different brine concentrations ranging from formation water salinity (FWS, 160,000ppm) to sea-water salinity (SWS, 32,895 ppm) and low salinity water (LSW, 2,000ppm) were contacted with a crude oil from the limestone formations of the Lansing-Kansas City group at reservoir temperature of 40 °C. Core flooding was performed on a properly aged Indiana limestone using the same crude oil and brine compositions as the reservoir with the effluent samples being taken for analysis. Another core flooding experiment conducted on a non-aged Indiana limestone rock hightlighted the potential of fluid-fluid interaction as a dominant recovery mechanism. Amott tests show the contribution of wettability alteration due to aging on improved oil recovery using low salinity waterflooding. A quantitative and qualitative analysis of the LKC crude oil-brine samples was conducted using Environmental Scanning Electron Microscopy (ESEM) imaging, Fourier Transform Infrared (FTIR) spectroscopy and Thermal Gravimetric Analysis (TGA) techniques This workflow helped with determination of the compositional changes that occurred when the crude oil came into contact with the various brine concentrations. They also provided a visual evidence to the fluid-fluid interaction phenomena experienced in low salinity waterflooding process.
The data show that LSW brine caused a greater change in the crude oil composition when they were contacted as compared to SWS brine and FWS. FWS created almost no change to the crude oil composition indicating the limited effect of FWS on the crude oil. These compositional changes in crude oil when contacted with LSW were attributed to the formation of water-in-oil microdispersions within the crude oil phase. FTIR data also showed that at brine concentration levels above 6000 ppm, this phenomena was not experienced. Oil production data for non-aged limestone cores showed an improved recovery of about 5% and 3% for SWS and LSW brines, respectively. Although, wettability alteration effect was minimized by the use of non-aged cores, improved oil recovery was still evident. This was interpreted to represent the formation of water-in-oil micro-dispersions of about 50µm in diameter for LSW. The formation of the micro-dispersions is believed to increase the sweep efficiency of the waterflood by swelling and therefore blocking of the pore throats causing the low salinity brine sweeping the unswept pore spaces.
SWS brine also experienced improved oil recovery when used as a displacing fluid. This observation was attributed to the change in dynaminc IFT measurement experienced using SWS brine as the continuous phase as compared to the use of LSW and FWS brines. This change caused a higher surface dilatational elasticity which leads to a suppression of the snap-off effect in coreflooding experiments hence causing improved oil recovery.
This paper presents the results obtained from decommissioning an offshore production loop (7.625 in., 19 km) by flushing with inhibited seawater and compares flow-assurance software simulations to data collected in the field.
After completion of the subsea production system shutdown, the production loop was pigged for dead oil removal, which was routed into the production unit separator. Once the dead oil was removed, the system was configured into a closed loop and flushed with a filtration spread (slurry skid, filter press, and polishing filter) to reduce the oil and grease content. Oil-absorbent additive was added to the typical oilfield diatomaceous earth filtration process, and the system was flushed until the oil-in-water content was reduced to less than 29 ppm (to meet local regulations). The completion of flushing for oil removal allowed for the disconnection and replacement of subsea structures, such as jumpers and manifold, in compliance with local regulations for oil-in-water content.
During the engineering phase before the offshore campaign, flow-assurance software simulations were used to verify that the proposed methodology would achieve the planned results. Based on these simulations, the production loop needed to be flushed 5.6 times its total volume to achieve the oil-in-water content specification. The offshore campaign required 5.9 flushes of the entire production loop volume and achieved an oil-in-water content of 3 ppm. Although software simulations and field results were similar, early filter-press saturation and washout produced issues during operations. For future operations, using an oily water separator before the filter press is recommended to extend the life of filtration/oil-absorbent media. The methodology validates the use of a filter press with oil-absorbent media as a cost-effective solution for oil removal in riser production or water injection loop systems.
The presented application is typically used during routine completion fluid diatomaceous earth filtration with no significant impact on filtration performance. Oil removal in compliance with the environmental limitations of oil and grease was successfully implemented for the production loop decommissioning and can be used in other systems with similar configurations.