Infinite Water: Implementation of Nanofiltration for Optimization of Vessel Stimulation Operations in the Offshore Greater Ekofisk Area, North Sea

2021 ◽  
Author(s):  
Irma Kusumawati ◽  
Samuel Edward Bremner ◽  
Neil McIntosh ◽  
Ingrid Rajkovic ◽  
Tanja Nylend

Abstract The incorporation of a sulfate removal system onto a stimulation vessel has been shown to positively affect vessel utilization, increase efficiency in field development, and reduce freshwater consumption. Stimulation vessels have fixed storage and transportation volumes as well as a fixed total mass that can be loaded. Fresh water occupies the highest proportion of space and mass in most stimulation treatments, which imposes limitations on all other products that can be loaded out. Particularly for acid stimulation treatments, a compromise between the volumes of raw acid and fresh water must be made in order to achieve the best operational efficiency possible. Any method that can reduce, eliminate, or replace fresh water as a component in stimulation fluids will have a significant impact on vessel efficiency. One option is the use of seawater as the base fluid. However, seawater can cause problems for well production due to the high sulfate content in the water leading to the formation of mineral scale. The solution to this problem has been the installation of a sulfate removal system on the stimulation vessel. Driven by membrane nanofiltration, this system can produce up to 100 m3/hr of low sulfate water from seawater for well stimulation operations. By removing the scaling risk from seawater, this system enables the stimulation vessel to maximize the products it loads with the ability to produce low sulfate water as and when it is needed. The sulfate removal system can reduce SO4 content to 4.3 mg/l and reduce other ions present in seawater. With an output of 100 m3/hr and being installed independently from stimulation systems, the unit is able to produce water regardless of ongoing activities. In stimulation jobs, multistage ball drop operations are the most time-critical operations. In the analysis of hundreds of stages stimulated with water from the new nanofiltration system, the average stage completion time was 6 hours, which included ball loading, dropping, and displacement; diagnostic injection testing; and the main treatment. With an average water requirement of 600 m3, the vessel can keep up with water demand and remove water capacity from the utilization equation. The use of a compact nanofiltration system for SO4 removal has improved stimulation vessel operations where scale production is a key concern for operators. In addition to increasing vessel utilization and intervention efficiency, the system will lead to the elimination of approximately 68,000 m3 of fresh water being pumped every year for stimulation operations in the North Sea.

2021 ◽  
Author(s):  
Mona Norbisrath ◽  
Jeannette Hansen ◽  
Kirstin Dähnke ◽  
Tina Sanders ◽  
Justus E. E. van Beusekom ◽  
...  

<p>The Elbe is the largest river entering the German Bight. Its estuary is a heavily used waterway connecting the sea to Germany’s biggest port in Hamburg. The Elbe navigation channel is continuously dredged, and agricultural fertilizer input from the catchment ensuing large phytoplankton blooms in the river Elbe exerts additional anthropogenic pressure. Biogeochemistry in the estuary is additionally governed by the North Sea and its strong tidal cycles, which ensure an exchange of fresh and marine waters.</p><p>The aims were to quantify the release of the carbon species total alkalinity (TA) and dissolved inorganic carbon (DIC) along the Elbe estuary, and to estimate the contribution of aerobe and anaerobe metabolic processes. Therefore, we used water samples collected continuously during a cruise in June 2019, to measure TA and DIC, and the stable isotopes of nitrate. We applied mass balances, to characterize the metabolic activity and detect their effect on the carbon species</p><p>The Elbe estuary could be subdivided into two parts: 1) an outer marine driven part, which is dominated by conservative mixing, also visible in higher TA than DIC values, and 2) an inner fresh water part in which metabolic processes play an important role.</p><p>We found a strong increase in TA and DIC (several hundred µmol kg<sup>-1</sup>) in the Hamburg port area, with higher DIC than TA values. We unraveled the water column impacts of nitrification and denitrification on TA and DIC by analyzing the stable isotopes δ<sup>15</sup>N-NO<sub>3</sub><sup>-</sup> and δ<sup>18</sup>O-NO<sub>3</sub><sup>-</sup>, and identified water column nitrification as a dominant pelagic process in the port of Hamburg and in the fresh water part further downstream. Because nitrification cannot explain the significant increase of TA and DIC in the port region, anaerobic processes such as denitrification in the sediment also appear to play an important role.</p><p> </p>


2020 ◽  
Author(s):  
Ryvo Octaviano ◽  
Erik Hornstra ◽  
Jonah Poort ◽  
Pejman Shoeibi Omrani ◽  
Ruud van der Linden ◽  
...  

2011 ◽  
Vol 51 (1) ◽  
pp. 589
Author(s):  
Kristian Aas ◽  
Lars Bjørheim

Gjøa was the largest field development project in Norway in 2010. Gjøa was proven in 1989 and are now being developed together with nearby Vega satellites. The combined reserves are estiThe recent Gjøa field development in the North Sea has many features that are relevant for the oil and gas developments north of Western Australia. While the field location is not very similar to the north of Western Australia, the field development solution is very relevant. Several subsea clusters are tied back to a semi-submersible platform with export of gas and condensate via pipelines to shore. Other aspects to the project that are relevant to Western Australia are split location engineering between Norway and India, fabrication of the hull in Korea and subsequent heavy lift transport to the assembly yard, pre-installation of the mooring system, and tow to field with ocean going tug boats. The semi concept, which was used for the Gjøa development, is a mature technology with few technical challenges on a conceptual level. On the other hand the building of an oil and gas platform for A$2 billion has many challenges, both economical and technical, that have to be solved to have a successful project for both the client and the contractor.


2020 ◽  
Vol 52 (1) ◽  
pp. 691-704 ◽  
Author(s):  
E. E. Taylor ◽  
N. J. Webb ◽  
C. J. Stevenson ◽  
J. R. Henderson ◽  
A. Kovac ◽  
...  

AbstractThe Buzzard Field remains the largest UK Continental Shelf oil discovery in the last 25 years. The field is located in the Outer Moray Firth of the North Sea and comprises stacked Upper Jurassic turbidite reservoirs of Late Kimmeridgian–Mid Volgian age, encased within Kimmeridge Clay Formation mudstones. The stratigraphic trap is produced by pinchout of the reservoir layers to the north, west and south. Production commenced in January 2007 and the field has subsequently produced 52% over the estimated reserves at commencement of development, surpassing initial performance expectations. Phase I drilling was completed in 2014 with 38 wells drilled from 36 platform slots. Platform drilling recommenced in 2018, followed in 2019 by Phase II drilling from a new northern manifold location.The evolution of the depositional model has been a key aspect of field development. Integration of production surveillance and dynamic data identified shortcomings in the appraisal depositional model. A sedimentological study based on core reinterpretation created an updated depositional model, which was then integrated with seismic and production data. The new depositional model is better able to explain non-uniform water sweep in the field resulting from a more complex sandbody architecture of stacked channels prograding over underlying lobes.


1991 ◽  
Vol 14 (1) ◽  
pp. 451-458 ◽  
Author(s):  
A. P. Hillier ◽  
B. P. J. Williams

AbstractDiscovered in 1966 and starting production in 1968, Leman was the second gas field to come into production in the UK sector of the North Sea. It is classified as a giant field with an estimated ultimate recovery of 11 500 BCF of gas in the aeolian dune sands of the Rotliegend Group. The field extends over five blocks and is being developed by two groups with Shell and Amoco being the operators. Despite being such an old field development drilling is still ongoing in the field with the less permeable northwest area currently being developed.


2021 ◽  
Author(s):  
Holger Brix ◽  
Norbert Kamjunke ◽  
Ingeborg Bussmann ◽  
Eric Achterberg ◽  
Peter Dietrich ◽  
...  

<p>Understanding river-sea-systems requires a thorough understanding of processes that span different Earth system compartments. To overcome issues related to the interaction of different scientific disciplines and compartments, such as different measurement and calibration standards, quality control approaches and data formats for specific environmental parameters, joint measurement campaigns have been initiated within the Helmholtz Association’s MOSES (Modular Observation Solutions for Earth Systems) project. Following multiple senor comparison and intercalibration campaigns in 2019, MOSES’ Hydrological Extremes event chain working group initiated joint field campaigns in summer 2020 covering the Elbe river from the Czech-German border to the tidal Elbe and further on into the estuary and the German Bight.</p><p>The fundamental objective was to establish scientifically sound and resilient multi-ship applicable sampling procedures and to create reference data for the main environmental parameters for future investigation of extreme events such as flooding and drought and their overall impact on the catchment region and the adjacent estuarine area of a large European fresh water / marine system. The campaign involved four research vessels, four research centers and spanned nearly two months. Measurements included standard hydrological and oceanographic parameters, as well as quantities relevant to the nutrient and carbonate system. Furthermore, selected water quality indicators and atmospheric measurements were performed. In the fresh water section of the Elbe river measurements were taken while drifting with the water mass. In the tidal section of the river sampling was done against the ebb current while in the North Sea a grid covering a large part of the German exclusive economic zone (EEZ) was sampled.</p><p>We detected a longitudinal increase of phytoplankton biomass along the 585 km freshwater part of the river towards the tidal system. In contrast, concentrations of dissolved nitrate and phosphate decreased to low values due the uptake by planktonic algae. The concentration of dissolved CO<sub>2</sub> decreased caused by increasing photosynthesis while the concentration of methane increased along the river stretch, particularly in the most downstream part when sedimentation of phytoplankton increased the organic load of sediments. The tidal part of the transect showed a strong influence of Hamburg harbor on almost all quantities, while downstream towards the estuary, the effects of the tidal cycle dominated variabilities. In the marine area, elevated chlorophyll concentrations were mainly found near the west coast of Schleswig-Holstein, probably mostly influenced by the Eider river outflow or the adjacent tidal flats. While most of the measured parameters showed an expected behavior relative to their individual compartments, the transfer of quantities between the compartments revealed rather complex and sometimes difficult to understand behaviors and patterns, especially when considering a functional quantitative analysis. The first results of this trans-compartment campaign showed that a quantitative understanding of the fate and dynamics of water constituents across compartments from the spring to the sea needs enhanced scientific collaboration and awareness to finally come to a better integrated understanding of physical, biogeochemical and biological processes from the local to the global scale.</p>


2006 ◽  
Vol 56 (7) ◽  
pp. 1539-1545 ◽  
Author(s):  
Håkon Dahle ◽  
Nils-Kåre Birkeland

A novel anaerobic, moderately thermophilic bacterium, strain Cas60314T, was isolated from hot oil-well production water obtained from an oil reservoir in the North Sea. The cells were Gram-negative, motile, straight rods. The salinity and pH growth optima were 2.0–3.0 % NaCl and 6.5–7.0, respectively. The optimum temperature was 58 °C. Strain Cas60314T had a fermentative type of metabolism and utilized proteinous substrates, some single amino acids and a limited number of organic acids, but not sugars, fatty acids or alcohols. Cystine and elemental sulfur were reduced to sulfide. The G+C content of the DNA was 46.6 mol%. On the basis of phenotypic and phylogenetic features, it is proposed that this isolate represents a novel genus and species with the name Thermovirga lienii gen. nov., sp. nov. within the family Syntrophomonadaceae. The proposed type strain is strain Cas60314T (=DSM 17291T=ATTC BAA-1197T).


1991 ◽  
Vol 14 (1) ◽  
pp. 295-300 ◽  
Author(s):  
D. G. Mound ◽  
I. D. Robertson ◽  
R. J. Wallis

AbstractThe Cyrus Oilfield is located in Block 16/28 of the UK sector of the North Sea approximately 250 km (155 miles) NE of Aberdeen and 55 km (34 miles) NE of the Forties Field. The trap consists of a broad, very low relief four-way dip closure developed over a deeper tilted fault block. The reservoir consists of submarine-fan sandstones of late Palaeocene age, belonging to the Andrew Formation. Provenance was to the NW resulting from the early Tertiary sea-level fall which exposed the East Shetland Platform. The reservoir has been sub-divided into two zones, an upper zone of interbedded sandstones and mudstones with net to gross ratios of 0.4 to 0.6 and sandstone porositites of 12% to 18%, and a lower zone of massive fine-grained sandstones plus subordinate thin shales and limestones, with net to gross ratios in excess of 0.9 and porosities averaging 20%. The reservoir is filled with undersaturated oil of 35° API and is normally pressured. The estimate of initial oil-in-place is 75 MMBBL. Development of the field is centred on the use of BP's SWOPS (Single Well Offshore Production System) vessel using two horizontal field development wells which feed into a single seabed template for offtake. Ultimate recovery from the field is estimated to be approximately 12 MMBBL.


2010 ◽  
Author(s):  
Martin Scott ◽  
Gustavo A. Carvajal ◽  
John Doug Manning ◽  
Nicholas Stuart Hendry ◽  
Michael Clive Rogers

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