|Publisher||Society of Petroleum Engineers||Language||English|
|Title||THE CALCULATION OF OIL TEMPERATURE IN A WELL|
|Authors||XIAO, ZU-QI, South Huang Hai Oil Corp.|
Unsolicited. This document was submitted to SPE (or its predecessor organization) for consideration for publication in one of its technical journals. While not published, this paper has been included in the eLibrary with the permission of and transfer of copyright from the author.
|Copyright||1987. Society of Petroleum Engineers|
For the efficient production of heavy crude, it is necessary to predict the temperature of the crude at the wellhead before designing or doing scientific research on oil field wellhead construction. However , to the author's knowledge, a suitable calculation method or formula has not been published except for a few empirical] formulae which are suitable only over a limited range. The author has applied the heat transfer equation and the law of conservation of energy to an oil well situation to develop a differential equation which when solved, gives a formula for the temperature of the crude in the well. A comparison of actual well data with the results as calculated from the formula showed the formula to be reliable and sufficiently accurate for use in design purposes.
In oil fields producing heavy, crude with high pour points, flow and therefore production is frequently only possible if surface production equipment is heated and/or insulated. Therefore before designing a wellhead or flowline in oil fields which produce heavy crude. It is desirable to determine if heating will be necessary. In order to determine if heating is required the temperature of the oil at the wellhead must be known. Thus it is important to know the temperature 04 crude in wellheads before production commences. However this can not be practically determined before production. As yet, this author is not aware of any reliable formula or appropriate method for determining the temperature prior to production. Furthermore, energy conservation has become increasingly important in recent years and the successful prediction of oil well temperature would allow a more precise determination of the quantity of heat required and this should significantly reduce wasted energy as a result of overheating. For example, when a programme of modernization was implemented in the older wells of the Shenli Oilfield, in the 1970's a rise in temperature was seen to be the result of the increase in water content in produced fluids and this increased through the life of the well. However the attendant temperature rise could not be predicted and led to the wellhead being frequently overheated. A reliable calculated method for the prediction of fluid temperature changes would have allowed a far greater efficiency, in the use of the wellhead heaters and this would have led to a significant energy saving. In short, the ability to successfully calculate the exact oil temperature in the wellhead would not only determine if heating is required and if it is, how much is necessary, but would aid the preproduction design of wellheads and surface facilities.
The problem of heating heavy crude was encountered when the DaQing Oilfield was first developed in the 1960's. For design purpose heavy crude temperature in the wellhead was taken as 18-22 degrees C, and this generalization was used in many other oilfields in China.
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