Grishagin, Aleksandr (SamaraNIPIneft) | Kologreeva, T. I. (SamaraNIPIneft) | Smirnov, A. V. (SamaraNIPIneft) | Shashel, V. A. (Rosneft) | Vakulenko, S. N. (Rosneft) | Savinova, I. V. (Impex Electro) | Kamashev, R. A. (Impex Electro)
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Following the problems related to transportation of high paraffine content oil at one of the fields of O??? "Samataneftegas?? we have investigated rheological properties of well products with abnormally high temperature of solidification (+36°?).
The essential dependence of viscosity vs temperature in the interval of velocity gradients from 20 to 300 sec-1 was determined: at 20°?- from 2799 up to 356 MPa*sec; at 30°? - from 177 up to 67.8 MPa*sec; at 40°? - 14.1 MPa*sec (Newton); 50°? - 7.8 MPa*sec (Newton).
Thus it was revealed, what at temperatures lower than 25°? it is possible to face the issue of paraffin fraction depositions into a solid phase, as well as the jellying of the product. This has been proved by numerous complete shut-downs of 159 x 6 mm operating pipeline and significant expenses for its rehabilitation.
The results of rheological tests have predetermined the search of means that allow resolving this problem. The only acceptable strategy in this case (in view of connecting new licensed areas) was the one to use the system of pipeline heating.
Such systems provide maintaining the temperature of transported product by compensating the heat losses from pipeline surface to the environment.
The problem is in the following, that 210 x 6 mm oil pipeline (having the overall length of 13.5 km of which 12.8 km should be heated) planned for construction, should be laid in a trench at the depth of not less than 1.6 m to the upper surface of the pipe.
The designing of such an object and its commissioning was done in Russia for the first time. To heat the underground sections of the oil pipeline they have used SKIN-system based on "skin-effect?? principle. The construction was carried out between December 2010 and October 2011. Pipeline was constructed between December 2010 and June 2011; installation of "skin-effect?? system was done between June 2011 and October 2011.
Oil pipeline with skin-system (mainitaining the temperature of 40°?) was commissioned on 11.14.2011 and tested in extremely cold period of the year. Till now it has transported around 75 thousand cubic meters of well products (860 m3/day in average).