Research on treating inorganic salt deposition in production wells of Tho Trang oil field

Abstract

The Tho Trang oil field, operated by the Russia - Vietnam Joint Venture -
Vietsovpetro, produced oil from the lower Miocene and upper Oligocene
sediments. After a long time of exploitation, the production wells at the
Tho Trang oil field have problems with salt deposition, which greatly
affects the efficiency of exploitation, a matter of concern to Vietsopetro.
Salt deposition, in general, has a complex composition. At the initial stage
of production, the most common components of deposition are Calcite
(CaCO3), Gypsum (CaSO4.2H2O), Anhydrite (CaSO4), Barite (BaSO4),
Asentin (SrSO4), Halite which is a mineral of NaCl. In addition to the
common minerals mentioned above, inorganic salt deposits may contain
other inorganic minerals such as: MgCO3, MgSO4, Ca(OH)2, Mg(OH)2,
Fe(OH)3, quartz - SiO2, Biotite - MgCl2.6H2O, CaF2,… and some organic
substances such as asphaltenes, resins, paraffins, some aromatic
compounds, high molecular weight compounds, etc. The phenomenon of
inorganic salt deposition has reduced the ability to exploit and transport
oil and gas due to reducing the permeability of the reservoir, causing
blockage of production wells, pipelines, and suction pumping systems.
There are many methods applied to control and deal with salt deposition.
One of them is the use of chemicals with special structures inhibiting the
formation and crystal growth of salt deposits. This paper presents
solutions to improve the efficiency of inorganic salt deposition treatment
at the Tho Trang oil field. The method of using chemicals to inhibit salt
deposition is the preferred method to maintain oil production. This is
considered to be the most advanced and effective method to keep
production well without being stopped