At present the majority of oil production companies clearly face the problems with field equipment failure risks through the salt depositions. These problems are allocated to various geological structures while developing the productive reservoirs as well as to physical and chemical properties of produced fluids. The associated water produced jointly with oil is the main source of salt deposition. This water is also used as well killing fluid during geo-physical well survey operations; it is also used during well routine servicing and work-over jobs. The process of salt deposition is mainly referred to drastic water over-saturation with hard-to-dissolve salts due to the reason of non-consistency in physical / chemical parameters of oil production system that is related to the changes of salt-organizing ions in their temperature, pressure and concentration. The chemical composition of inorganic sediments is mainly presented by sulfates and calcium carbonates (anhydrites, gypsum, calcite), barium sulfates (barites) and strontium sulfates (celestite), oxides, carbonates and iron sulfides.
In order to evaluate the risks of salt depositions Samaraneftegas jointly with SamaraNIPIneft have conducted scientific research program where they have studied 10-component formation and well-site water composition at well-killing fluid storage facility at the operating fields of the Company, including the quantitative composition of sedimentation ions (cations of Ca2+; Mg2+; Ba2+; Sr2+; Fegen; Na++K+; anions of SO42-; CO32-; HCO3-; Cl-). Within the frames of these works they have defined the water tendency to salt shows and have conducted physical and mathematical simulation of water compatibility. In course of simulation studied it was found that while mixing water from productive formations with well-killing fluids from storage facilities the strontium sulfate may severely affect the operation of both bottom-hole and surface process equipment and pipelines being one of the salt-generating components.
References
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2. Kudinov V.I., Suchkov B.M., Metody povysheniya proizvoditel'nosti skvazhin (Methods of well productivity increasing), Samara: Samarskoe knizhnoe izdatel'stvo Publ., 1996, 411 p.
3. Chistovskiy A.I., Popov I.P., Izuchenie podzemnykh vod neftyanykh mestorozhdeniy i razvedochnykh ploshchadey na soderzhanie v nikh poleznykh komponentov (The study of groundwater of oil fields and exploration areas for the content of valuable component), Kuybyshev, 1990, 153 p.
