scholarly journals Elasto-viscoplastic modeling of subsidence above gas fields in the Adriatic Sea

Author(s):  
Fabrizio Gemelli ◽  
Anna Corradi ◽  
Giorgio Volonté ◽  
Stefano Mantica ◽  
Michela De Simoni

Abstract. From the analysis of GPS monitoring data collected above gas fields in the Adriatic Sea, in a few cases subsidence responses have been observed not to directly correlate with the production trend. Such behavior, already described in the literature, may be due to several physical phenomena, ranging from simple delayed aquifer depletion to a much more complex time-dependent mechanical response of subsurface geomaterials to fluid withdrawal. In order to accurately reproduce it and therefore to be able to provide reliable forecasts, in the last years Eni has enriched its 3D finite element geomechanical modeling workflow by adopting an advanced constitutive model (Vermeer and Neher, 1999), which also considers the viscous component of the deformation. While the numerical implementation of such methodology has already been validated at laboratory scale and tested on synthetic hydrocarbon fields, the work herein presents its first application to a real gas field in the Adriatic Sea where the phenomenon has been observed. The results show that the model is capable to reproduce very accurately both GPS data and other available measurements. It is worth remarking that initial runs, characterized by the use of model parameter values directly obtained from the interpretation of mechanical laboratory tests, already provided very good results and only minor tuning operations have been required to perfect the model outcomes. Ongoing R&D projects are focused on a regional scale characterization of the Adriatic Sea basin in the framework of the Vermeer and Neher model approach.

2014 ◽  
Vol 1073-1076 ◽  
pp. 2244-2247
Author(s):  
Hu Sun ◽  
Zhi Jun Ning ◽  
Zu Wen Wang ◽  
Zhen Li ◽  
Zhi Guo Wang

Erosion is a main failure of tubings and downhole tools in Changqing gas field. It is necessary to evaluate the erosion rate for the safety of tubing and strings. In this paper, the erosion of P110 steel, in the 0.2%wt guar gum fracturing fluid which contains sands, is investigated by weight loss method in the self-made jet experiment device. It is indicated that the erosion rate increases with the increment of slurry velocity exponentially. When the slurry velocity is in low velocity area, the electrochemical corrosion of dissolved oxygen dominates in erosion mechanism; when slurry velocity increases into middle velocity area, the weight loss is controlled by the synergism of corrosion-erosion; and when the slurry velocity increases into high velocity area, the weight loss rate is dominantly depended on erosion of particles. The results can provide guidelines for large-scale fracturing work of Changqing gas fields.


2021 ◽  
Author(s):  
Tran Nguyet Ngo ◽  
Lee Thomas ◽  
Kavitha Raghavendra ◽  
Terry Wood

Abstract Transporting large volumes of gas over long distances from further and deeper waters remains a significant challenge in making remote offshore gas field developments technologically and economically viable. The conventional development options include subsea compression, floating topside with topside compression and pipeline tie-back to shore, or floating liquefied natural gas vessels. However, these options are CAPEX and OPEX intensive and require high energy consumption. Demand for a lower emission solution is increasingly seen as the growing trend of global energy transition. Pseudo Dry Gas (PDG) technology is being developed by Intecsea, Worley Group and The Oil & Gas Technology Centre (Aberdeen) and tested in collaboration with Cranfield University. This is applied to develop stranded or remote gas reserves by removing fluids at the earliest point of accumulation at multiple locations, resulting in near dry gas performance. This technology aims to solve liquid management issues and subsequently allows for energy efficient transportation of the subsea gas enabling dramatic reductions in emissions. The PDG prototype tested using the Flow Loop facilities at Cranfield University has demonstrated the concept’s feasibility. Due to a greater amount of gas recovered with a much lower power requirement, the CO2 emissions per ton of gas produced via the PDG concept is by an order of magnitude lower than conventional methods. This study showed a reduction of 65% to 80% against standard and alternative near future development options. The paper considers innovative technology and a value proposition for the Pseudo Dry Gas concept based on a benchmarked study of a remote offshore gas field. The basin was located in 2000m of water depth, with a 200km long subsea tie-back. To date the longest tieback studied was 350km. It focused on energy consumption and carbon emission aspects. The conclusion is that decarbonisation of energy consumption is technically possible and can be deployed subsea to help meet this future challenge and push the envelope of subsea gas tie-backs.


Methane ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 24-37
Author(s):  
Muhammad Alfiza Farhan ◽  
Yuichi Sugai ◽  
Nuhindro Priagung Widodo ◽  
Syafrizal Syafrizal

The leakage of methane from the subsurface on the coalfield or natural gas field invariably becomes an important issue nowadays. In notable addition, materials such as activated carbon, zeolites, and Porapak have been successfully identified as adsorbents. Those adsorbents could adsorb methane at atmospheric pressure and room temperature. Therefore, in this scholarly study, a new method using adsorbents to detect points of methane leakage that can cover a wide-scale area was developed. In the beginning, the most capable adsorbent should be determined by quantifying adsorbed methane amount. Furthermore, checking the possibility of adsorption in the column diffusion and desorption method of adsorbents is equally necessary. The most capable adsorbent was activated carbon (AC), which can adsorb 1.187 × 10−3 mg-CH4/g-AC. Hereinafter, activated carbon successfully can adsorb methane through column diffusion, which simulates the situation of on-site measurement. The specific amount of adsorbed methane when the initial concentrations of CH4 in a bag were 200 ppm, 100 ppm, and 50 ppm was found to be 0.818 × 10−3 mg-CH4/g-AC, 0.397 × 10−3 mg-CH4/g-AC, 0.161 × 10−3 mg-CH4/g-AC, respectively. Desorption of activated carbon analysis shows that methane concentration increases during an hour in the temperature bath under 80 °C. In conclusion, soil methane leakage points can be detected using activated carbon by identifying the observed methane concentration increase.


2020 ◽  
Author(s):  
Sudad H Al-Obaidi

Practical value of this work consists in increasing the efficiency of exploration for oil and gas fields in Eastern Baghdad by optimizing and reducing the complex of well logging, coring, sampling and well testing of the formation beds and computerizing the data of interpretation to ensure the required accuracy and reliability of the determination of petrophysical parameters that will clarify and increase proven reserves of hydrocarbon fields in Eastern Baghdad. In order to calculate the most accurate water saturation values for each interval of Zubair formation, a specific modified form of Archie equation corresponding to this formation was developed.


The Holocene ◽  
2019 ◽  
Vol 30 (1) ◽  
pp. 53-64
Author(s):  
Antonio Cascella ◽  
Sergio Bonomo ◽  
Bassem Jalali ◽  
Marie-Alexandrine Sicre ◽  
Nicola Pelosi ◽  
...  

New information on palaeoenvironmental conditions over the past ~2700 years in the Central Mediterranean Sea have been acquired through the high-resolution study of calcareous nannofossils preserved in the sediment core SW104-ND14Q recovered in the Southern Adriatic Sea (SAS) at 1013-m water depth. The surface water properties at this open SAS site are sensitive to atmospheric forcing (acting both at local and regional scale) and the North Ionian Sea driven inflowing waters. Our data show a relationship between reworked coccolith abundances, flood frequency across the Southern Alps and the North Atlantic Oscillation (NAO) confirming their value as indicator of runoff/precipitation. Changes in the abundance of the opportunistic (r-strategist) species Emiliania huxleyi and deep dweller taxa Florisphaera profunda were used to reconstruct the upper water column stratification and associated changes in coccolithophorid productivity. The negative correlation between reworked coccoliths and the N-Ratio ( r = −0.44; p = 6−7) suggest that fresh water induced stratification is a controlling factor of the SAS coccolithophorid production. High coccolithophorid productivity levels occurred during dry periods and/or time intervals of inflowing salty and nutrient-rich Levantine Intermediate Waters favouring convection while lower levels took place during high freshwater discharge, mainly during the ‘Little Ice Age’ and two centennial scale intervals of weakest NAO around 200 BCE and 500 CE.


2011 ◽  
Vol 51 (2) ◽  
pp. 684
Author(s):  
Peter Cook ◽  
Yildiray Cinar ◽  
Guy Allinson ◽  
Charles Jenkins ◽  
Sandeep Sharma ◽  
...  

Successful completion of the first stage of the CO2CRC Otway Project demonstrated safe and effective CO2 storage in the Naylor depleted gas field and confirmed our ability to model and monitor subsurface behaviour of CO2. It also provided information of potential relevance to CO2 enhanced gas recovery (EGR) and to opportunities for CO2 storage in depleted gas fields. Given the high CO2 concentration of many gas fields in the region, it is important to consider opportunities for integrating gas production, CO2 storage in depleted gas fields, and CO2-EGR optimisation within a production schedule. The use of CO2-EGR may provide benefits through the recovery of additional gas resources and a financial offset to the cost of geological storage of CO2 from gas processing or other anthropogenic sources, given a future price on carbon. Globally, proven conventional gas reserves are 185 trillion m3 (BP Statistical Review, 2009). Using these figures and Otway results, a replacement efficiency of 60 % (% of pore space available for CO2 storage following gas production) indicates a global potential storage capacity—in already depleted plus reserves—of approximately 750 Gigatonnes of CO2. While much of this may not be accessible for technical or economic reasons, it is equivalent to more than 60 years of total global stationary emissions. This suggests that not only gas—as a lower carbon fuel—but also depleted gas fields, have a major role to play in decreasing CO2 emissions worldwide.


Author(s):  
Hualei Yi ◽  
Yun Hao ◽  
Xiaohong Zhou

Abstract For deepwater subsea tie-back gas field development, hydrate tends to be formed in deepwater subsea production system and gas pipeline due to high pressure and low temperature. Based on the gas field A development, this paper studies the selection of hydrate inhibitors and injection points, i.e. different injection points with different inhibitors. Transient and steady flow simulations are performed using the OLGA software widely used for multiphase flow pipeline study in the world. The produced water flow rate affects the hydrate inhibition in case of well opening, including cases of different times with different water temperatures. This paper presents the calculation of the maximum inhibitor injection rate in the subsea pipeline by taking the whole production years into consideration. The measures on hydrate remediation are taken by quickly relieving the subsea pipeline pressure from wellheads and the platform according to different hydrate locations. Now more and more deepwater gas fields are developed in South China Sea and around the world. The experience obtained from the gas field A development will benefit the hydrate inhibition for future deepwater gas field development.


2019 ◽  
Vol 59 (2) ◽  
pp. 803
Author(s):  
Abdul Qader ◽  
Jai Kant Pandit

CO2CRC, in collaboration with the University of Melbourne and the University of New South Wales, is testing two novel CO2 capture technologies designed for both on-shore and off-shore natural gas applications in a state-of-the-art experimental capture rig at CO2CRC’s Otway National Research Facility. The goal is to develop robust and compact technology for high pressure natural gas separation over a range of adjusted high CO2 concentrations mimicking various gas field conditions. These technologies would facilitate developing new gas fields to recover methane in a cost-effective manner which is currently uneconomical with conventional technologies. In the first stage of testing, commercially available materials (adsorbents and membranes) were used for benchmarking. Results from both adsorbent and membrane technologies are encouraging with respect to recovery and purity of CO2 and methane with the prospect of commercial application.


2019 ◽  
Vol 91 ◽  
pp. 07023
Author(s):  
Victor Volkov ◽  
Nikita Volkov

The paper considers the problematic issues of the special aspects of solution of the problems of modern geodynamics and technogenic geomechanics in oil and gas fields based on the results of re-levelling. The disadvantages and fundamental errors traditionally made by mining and land surveyors in organizing and performing re-levelling on the territories of oil and gas fields are given. The results of high precision levelling, obtained on the territory of an oil and gas field using the program and goal-oriented approach for its formulation, are presented. The representativeness and sufficient accuracy of obtaining the results of re-levelling allowed us to establish significant speeds of geodynamic and technogenic displacements of the earth’s surface (0.4 - 3.6 mm/year) in the shortest time possible with high economic efficiency.


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