Underground Loss Research Articles

Methods for Large-Scale Monitoring of District Heating Systems Using Airborne Thermography

District heating is a common way of providing heat to buildings in urban areas. The heat is carried by hot water or steam and distributed in a network of pipes from a central power plant. It is of great interest to minimize energy losses due to bad pipe insulation or leakages in such district heating networks. As the pipes generally are placed underground, it may be difficult to establish the presence and location of losses and leakages. Toward this end, this work presents methods for large-scale monitoring and detection of leakages by means of remote sensing using thermal cameras, so-called airborne thermography. The methods rely on the fact that underground losses in district heating systems lead to increased surface temperatures. The main contribution of this work is methods for automatic analysis of aerial thermal images to localize leaking district heating pipes. Results and experiences from large-scale leakage detection in several cities in Sweden and Norway are presented.

Analysis of Oil-field Water Problems

The underground losses of oil exceed by hundreds of thousands of barrels allthe oil that has been lost in storage, transportation, or refining. Thequantity lost is, of course, indeterminate; but when it is considered that thecontents of an entire oil field have been excluded from recovery by invadingwaters, some idea of the amount wasted may be gained. Similarly, enormousquantities of gas have been lost underground. Conservation of the oil, therefore, should start before it is brought to the surface rather than afterit is placed in storage tanks. Water is one of the most important causes for underground losses and theoperator should give as serious consideration to an underground flood of wateras he would to a destructive surface flood. The best insurance, of course, isto have the wells drilled in such a manner that water has no access to theproductive oil and gas horizons, and on abandonment the wells should beproperly plugged. The encroachment of edge water and the occurrence of water in the base of anoil sand present a very serious problem to an oil company sooner or later thesewaters are bound to cause considerable damage, if they do not entirely destroythe possibilities of further production. Too often, however, a field has beenconsidered to be in a hopeless condition, whereas wells in as bad a conditionin other areas have been repaired and the life of the field appreciablylengthened. The corrections are very often suggested by technical study. Verysuccessful results have been accomplished by detailed underground work in theCalifornia oil fields, in Cushing, Oklahoma, and in other areas. The purpose of this paper is to outline briefly general methods of analyzingoil-field water problems in a producing or in a producing and developing oilfield, with a view to suggesting repair work on offending wells. Reference iscontinually made to producing oil wells; the same general method of procedure, however, should be adopted in a gas field. AIME 065–27