Ph.D. Theses

Development of new effective bactericides-inhibitors on the basis of a research into the causes and levels of infection with microorganisms through the example of Zhetybai field

Bisenova Miua Allaberdiyevna

2525.01 - Development and exploitation of oil and gas fields

Underground and aboveground oil field equipment constantly contacts with emulsion-type heterogenous systems, or a system of fluids immixing at interface.

In this case, the major source of oil production-transportation-storage system corrosion activity is mineralized injected, waste, produced water containing Сl-, SO42-, Fe3+ -ions, acid gases- H2S, CO2, depolarizer - O2, different-type microorganisms.

It is known that oils of West Kazakhstan fields, and particularly Zhetybai (Jetibay) field contain sufficiently great amount of corrosive gases H2S,CO2 tragically strengthening corrosive processes of pitting character. In equipment, rust-through damages occur that result in frequent failures and environmental degradation. Moreover, great problems arise in oil producing wells, particularly in places of oil well tubing thread connections leading to breakage and tubing string parting.

Therefore, in the dissertation, results of researches into the causes and levels of infection with microorganisms of Zhetybai (Jetibay) field were presented and a number of new bactericides-inhibitors and lubricants were suggested on their basis.

It was established that in the long-term usage process of Zhetybai (Jetibay) field oil equipment, corrosive processes progress through sulphureous mechanism of biogenous origin (microbiological corrosion). St.20- make steel corrosion rate values were obtained directly in pressure and production wells.

It was identified that long-term usage of Zhetybai (Jetibay) field surface injection waters led to its high infection with microorganisms and, as consequence to equipment hydrogen-sulfide corrosion. It was shown that we should intimately examine impact of used surface waters on cationic and anionic composition, concentration, salt load, availability of SO42- – anion, gases, and temperature of produced waters during their mixing with underground waters with the view of eliminating favourable conditions for microorganism reproduction in Zhetybai (Jetibay).

On the basis of available raw product, as well as Kazakhstan production, blend compositions with highly inhibiting properties were developed.

It was shown that vacuum gasoil and soap stock can be used as admix for regulating oil rheological properties in Zhetybai (Jetibay) and successfully applied in the case of difficulty occurrence during well production exploitation and transportation.

Sealing composition for hydrogen-sulfide corrosion protection of thread connections was developed. With regard to raw product availability and high efficiency from hydrogen-sulfide corrosion, it is recommended to jointly use it with a bactericidal and inhibitory protection method.

Developed bactericide-inhibitor “Oilgas-2013” was successfully tested on a gas pipeline in “Oil Rocks” field. With regard to identity of process mediums and corrosion activity with Zhetybai (Jetibay) field, bactericide-inhibitor “Oilgas-2013” is recommended for microbiological corrosion protection of oil field equipment of this field.