Fiber optic technology is based on exposing the fiber to periodic ultraviolet UV light patterns that induce a "grating" on it. Pressure and temperature variations change the reflection wavelength of the gratings and can be decoded with respect to the fixed, incipient operating wavelength. The system is self-referencing. Every point distributed along the length of the fiber has the potential to generate a different temperature measurement.
The advantages are measurement of a permanent temperature gradient over the length of the fiber and the ability to select specific measurement points. In one reported case, temperature measurements taken along a horizontal wellbore at different times showed steamchests, water breakthrough, crossflow, and flow behind pipe. Pressure is measured by sensors located at discrete, fixed points along the fiber.
At the sensors, the fiber is cut, and its ends are placed face-to-face in a proximal arrangement. The face-to-face spacing is measured by successive reflections of the light wave. Changes in the value of the spacing reflect the environmental pressure around the fiber at that point. The self-referencing technique uses the distributed temperature measurement for suitable corrections.
Although the focus of this article is bottomhole measurements, it is worthwhile to mention a few interesting points about the environments of surface and subsea measurements. The temperature specification in particular presents no obstacle to testing operations in extremely cold areas, such as the Arctic and similar cold-weather territories. Pressure and temperature measurements are sometimes required at the subsea tree level.
The measurements are mainly used to monitor the operating conditions of the landing string near the ocean floor. Applications include ensuring that the maximum temperature rating of the elastomers in the blowout preventer BOP is not exceeded, and providing data to help prevent hydrate formation during deep-sea cleanup and well testing operations.
Use this section to list papers in OnePetro that a reader who wants to learn more should definitely read. Use this section to provide links to relevant material on websites other than PetroWiki and OnePetro. Bottomhole pressure and temperature gauges. Pressure transducer technology. Water has two unique characteristics: it is a very poor conductor of heat and it has a great capacity to hold energy.
In other words, iit takes a lot of energy to raise the temperature of water, but once the temperature is raised, the heat energy is dissipated very slowly. When sunlight strikes the surface of water, it heats the top layers most readily. The sunlight is transmitted by the water only enough to heat lower levels a little bit. In the ocean, most of the light energy is absorbed in the top 50 centimeters. Since water has a high capacity to hold on to hea - once heated it stays hot for a time, seasonal changes in ocean temperatures lag about 2 months behind land temperatures.
So in temperate climates, the ocean is much warmer for swimming in the fall than in the spring. This temperature lag is even greater in deeper layers of larger lakes and in oceans.
The lag can stretch to as long as 5 months Russell-Hunter, Heat is transferred to lower levels of lakes, ponds, and oceans largely by the circulation of the body of water. Water circulation is caused by the movement of water molecules between areas of different densities. Generating electricity creates a lot of wasted energy in the form of heat, which then needs to be cooled before it can be discharged into the environment.
Related content. New weapon in fight against invasive aquatic weeds. Media Release. Feature story. Measuring copper and zinc in urban waterways. The future shape of water. Eutrophication Explorer. Kappelmeyer O, Haenel R Geothermic with special reference to application. Kutasov IM Applied geothermics for petroleum engineers. Elsevier, Amsterdam. J Geophys Eng — Article Google Scholar.
Kutasov IM, Eppelhaum LV A new method for determining the formation temperature from bottom-hole temperature logs. J Pet Gas Eng 1 1 — Robertson EC Thermal conductivity of rocks. Survey, open file report J Geophys Res — Springer, Berlin, pp 36— Download references. You can also search for this author in PubMed Google Scholar. Correspondence to Mohammad Ali Kargarpour. Reprints and Permissions. Kargarpour, M. Investigation of reservoir temperature in a gas reservoir in Middle East: case study.
J Petrol Explor Prod Technol 7, — Download citation. Received : 22 May Accepted : 31 July Published : 09 August Issue Date : June Anyone you share the following link with will be able to read this content:. Sorry, a shareable link is not currently available for this article. Provided by the Springer Nature SharedIt content-sharing initiative. Skip to main content. Search SpringerLink Search. Download PDF. Abstract Having a good estimation of geothermal gradient and the reservoir temperature has a great impact on the methodological reservoir management in the entire reservoir life, from natural depletion phase up to draining the last portion of hydrocarbon by applying an appropriate EOR method.
Introduction Having a good estimation of geothermal gradient and the reservoir temperature has a great impact on the methodological reservoir management; however, as temperature is measured by wire line tools, its determination encounters the same difficulties as reservoir pressure measurement.
General down-hole temperature profile. Full size image. Unaccomplished temperature change versus time and radius. Individual temperature profile of wells. Temperature profile of wells based on filtered-out data.
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