Towards a Quality-of-Thing based Approach for Assigning Things to Federations

In the context of an Internet-of-Things (IoT) ecosystem, this paper discusses 2 necessary stages for managing federations of things. The first stage defines things in terms of duties and non-functional properties that define the quality of these duties. And, the second stage uses these properties to assign appropriate things to future federations. Specialized into adhoc and planned, federations are expected to satisfy needs and requirements of real-life situations like traffic control that arise at run-time. A set of experiments using a mix of real and simulated datasets, demonstrate the technical doability of thing assignment to federations and are presented in the paper, as well

Geological evolution of the offshore Tunisia (Gabes Basin, Pelagian Domain) since the Cretaceous : constraints from subsidence curves from hydrocarbon wells data

The comparison of subsidence curves obtained from deep wells in sedimentary basins represents a powerful tool to identify major changes in subsidence distribution, both in time and space. The construction of subsidence curves from 19 wells, covering a time interval from the Cretaceous to the present in the Gabes Basin (Pelagian Domain of the eastern Tunisian Platform), provided the opportunity to reconstruct the subsidence patterns across the basin. Changes in the subsidence rates in different wells allowed the identification of six time-intervals (stages). Stage boundaries are defined by major changes in subsidence trends in the 19 wells: each stage is characterized by changes in the subsidence pattern of groups of wells, likely reflecting episodes of re-organization of the distribution of domains with different trends (increase or decrease) of subsidence. Comparisons among the subsidence curves highlighted, for each stage, parts of the basins with higher or lower subsidence, permitting to identify highs and lows and to reconstruct their significance in the different stages identified. The basin-scale changes in the distribution of subsidence rates reflect regional events of basin re-organization, potentially controlled by syndepositional faults or, for some stages, by halokinesis, due to the presence of salt deposits in the southern part of the study area. The comparison of the subsidence curves permitted to identify domains characterized, in different time intervals, by different patterns of subsidence rates, providing important elements for the characterization of the different stages in the stratigraphic and tectonic evolution of the basin

Effect of Compositional Grading On reservoir Performance

In reservoirs with thickness exceeding fifty meters, compositional guiding has been found to cause significant variation in performance. Main fluid properties, governing the magnitude of reservoir performance, such as density; formation volume factor and fluid viscosity experience variation due to varying fluid composition along the hydrocarbon column. These variations cause erroneous estimation of stock-tank oil in place and may infer reservoir engineers to consider inappropriate secondary oil recovery methods, for example. In the presence of gravity segregation within the oil column, heavy ends will form a heavy oil blanket in the lower part of the reservoir. Such a scenario may result in poor displacement and an earlier breakthrough when water drive is the dominant fluid flow mechanism. In this paper reservoir performance due to varying reservoir fluid composition has been examined using  reservoir simulation analysis and recommendations for better characterization of reservoir fluid sampling are outlined

Appropriate Separator Sizing: A Modified Stewart and Arnold Method

Oil and gas separators were one of the first pieces of production equipment to be used in the petroleum industry. The different stages of separation are completed using the following three principles: gravity, centrifugal force, and impingement. The sizes of the oil droplets, in the production water, are based mainly on the choke valve pressure drop. The choke valve pressure drop creates a shearing effect; this reduces the ability of the droplets to combine. One of the goals of oil separation is to reduce the shearing effect of the choke. Separators are conventionally designed based on initial flow rates; as a result, the separator is no longer able to accommodate totality of produced fluids. Changing fluid flow rates as well as emulsion viscosity effect separator design. The reduction in vessel performance results in recorded measurements that do not match actual production levels inducing doubt into any history matching process and distorting reservoir management programs. In this paper, the new model takes into account flow rates and emulsion viscosity. The generated vessel length, vessel diameter, and slenderness ratio monographs are used to select appropriate separator size based on required retention time. Model results are compared to API 12J standards

Field application of phenol formaldehyde gel in oil reservoir matrix for water shut-off purposes

A few wells from a major western India on-shore oil field are either on the verge of being shut in or have already been abandoned due to excessive water-cut (WCT) levels. Low injectivity and extreme temperatures (149C) make it difficult for water shut-off by conventional polymer gel injection. A water-thin monomer-based in situ gelation system has been developed and successfully tried in one of the wells that ceased production due to 100% WCT. The average production of 420 barrel of oil per day (BOPD) with less than 1% WCT, in the first year of production back in 1996, has declined to less than 8 BOPD (with 98% WCT) prior to shut-in in year 2002. A rise in the oil-water contact level in combination with a coning effect was diagnosed as a possible cause of the high WCT, which was later controlled by a newly developed gelant treatment. In fact, the average post-treatment production for the first 3 months was nearly 200 BOPD. Thereafter, production gradually stabilized in the neighborhood of 115 BOPD with a WCT of 48%. Cheap chemicals and a fast treatment method have resulted in a payback time span of 5 days and made an additional profit of U.S. $0.6 M. The water shut-off job resulted in an impressive commercial success; technical success, however, was less than satisfactory due to the fact that, in spite of using a water-thin monomeric solution, only 40% of the designed volume could be injected due to low injectivity resulting in an abnormal pressure build-up. In addition to the gel development and treatment experiences, this article describes in detail the results of further lab investigations carried out to identify the possible reasons causing injection failure