Temperature Measurements In Wells Research Articles

New estimates of the influence of paleoclimate on the vertical distribution of heat flow

The study of deep continental boreholes revealed significant vertical variations in heat flow. This fact still has no satisfactory explanation. One possible cause could be the effects of past climate changes, namely changes in the Earth's surface temperature. The paper discusses some consequences of accounting for the influence of paleoclimate on the measured heat flow using the example of the platform part of the Republic of Bashkortostan. A numerical simulation of the influence of paleoclimate on the distribution of the thermal field in the borehole was performed using two models of past climate changes. The first model, adopted earlier, includes two major climatic episodes of the past, the Würm glaciation 80–10 thousand years ago, and the Little Ice Age, 600–150 years ago. The second model uses the climatic curve for the Meso-Cenozoic, which additionally takes into account the warming that began about 65 Ma, reached its maximum about 45 Ma, and followed by a cooling that continued with some fluctuations until the present time [Velichko, 1987]. It is shown that, in the analysis of vertical variations in heat flow, the use of a model of past climate changes, taking into account more distant large climatic events than has been done previously, allows us to estimate the paleoclimate influence as much more significant than previously thought. However, at this stage of the research, with the accepted models of temperature changes at the Earth's surface, the vertical variations of the heat flow established by the results of experimental geothermal studies cannot be explained only by the influence of the paleoclimate. To solve the problem, we need a detailed study of the thermophysical properties of rocks, high-quality temperature measurements in wells, and improvement of the model of past climate changes in the region under study.

Methodology Specific Features of Underground Water Thermomonitoring at the Bucher-1 NPP Site in the Islamic Republic of Iran

The article presents some of the possibilities of thermometry when monitoring groundwater at the Bushehr-1 NPP. Possible sources of local anomalies of the temperature field recorded in the wells are considered. It is shown that temperature measurements allow, incl. to determine the important features of the operation of the monitoring system wells, their design characteristics, the integrity of the casing strings and the power sources of the aquifers. And in the conditions of the Bushehr-1 NPP site, which is known to be in a complex seismotectonic environment, temperature monitoring is of particular additional importance. Monitoring temperature measurements in wells provide more information about changes in the hydrogeodynamic field before tectonic events compared to traditional measurements of the liquid column level. For this reason, temperature monitoring at the Bushehr NPP site should become a part of specialized seismic monitoring aimed at the safe operation of the NPP in difficult seismotectonic conditions in the Zagros zone and the adjacent part of the Iranian coast of the Persian Gulf.

Predicting Flow Distribution for SAGD Producing Wells By Use of Permanently Installed Fiber Optics

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper SPE 102159, "Predicting the Flow Distribution on Total E&P Canada's Joslyn Project Horizontal SAGD Producing Wells Using Permanently Installed Fiber-Optic Monitoring," by P. Krawchuk, SPE, and M.A. Beshry, Total E&P Canada, and G.A. Brown, SPE, and B. Brough, SPE, Schlumberger, prepared for the 2006 SPE Annual Technical Conference and Exhibition, San Antonio, Texas, 24-27 September. During the startup and early operation of horizontal steam-assisted gravity-drainage (SAGD) wells, it is important to understand the flow distribution of bitumen and water along the horizontal reservoir interval so steam distribution can be adjusted to optimize the startup and early operation of the SAGD pair. The injector/producer interval between SAGD wells was modeled with a thermal reservoir model. The results highlight the need for distributed temperature measurements in SAGD wells to understand the temperature response over time. Introduction The Joslyn field is west of the Athabasca River in Alberta, Canada. The McMurray formation is a 50-m-thick high-permeability sand at 60 to 100 m below the surface and contains high-viscosity bitumen. On the western part of the lease, the recovery method is SAGD, which requires injection of steam into an upper horizontal well, creating a steam chamber and reducing the viscosity of the bitumen. The bitumen and condensed steam flow by gravity down into the producer well 5 m below the injector, and from there they are pumped to the surface. A pilot horizontal injector/producer pair was installed in the Joslyn field in 2004 as Phase I of reservoir development. During completion of the SAGD pair in Phase I, a fiber-optic distributed temperature system (DTS) was installed in the producer well, and data from this were monitored as the well was put on production. In January 2005, a workover was performed. Temperature monitoring along the wellbore with the DTS system continued through 2005. Joslyn Completion The upper and lower horizontal wells were completed with slotted liners along the reservoir interval. The upper steam-injection well had injection tubing to the toe of the well, allowing steam to be injected at the heel, toe, or a combination of both. The production well initially was completed with no tailpipe along the reservoir interval. The downhole instrumentation string consisting of bubble tube and optic fiber in its 1/4-in. control line was deployed inside 1 1/2-in. coiled tubing (CT), which was inserted along the reservoir interval. In addition to the optic fiber, three vertical observation wells intersected the horizontal well trajectory between 1 and 2 m from the SAGD wells. These were at the heel, midway, and at the toe of the horizontal wells. Temperature measurements in these wells were provided by a string of 30 thermocouples that were monitored regularly.

Reconstruction of the surface temperature of arctic glaciers from the data of temperature measurements in wells

Consideration is given to the problem of reconstruction of the surface temperature of a glacier from the data of measuring the temperature in a well. Mathematically this problem is an inverse problem for a heat‐conduction equation and refers to a number of incorrectly formulated (ill‐posed) problems. For the reconstruction of the surface temperature, the Tikhonov regularization method has been used. A model that takes into account the vertical advection of the annual layers has been adopted as a mathematical model that describes the propagation of heat in a glacier. The boundary temperatures have been reconstructed from the results of temperature measurements in wells obtained for certain glaciers of the Arctic. The effect of the initial temperature distribution, the accumulation rate, and the magnitude of the geothermal heat flux on the reconstructed boundary temperature has been investigated.

Temperature Measurements in Wells in Southeastern Turkey: GEOLOGICAL NOTES

Temperature Measurements in Wells in Southeastern Turkey: GEOLOGICAL NOTES