Status of Fungicide Used in Oil Field

There are a large number of microorganisms, including bacteria, molds, viruses, algae and protozoa, that can promote the material circulation in nature, but also bring great harm to the oil field, they can cause the equipment And the plugging of pipelines and water injection wells can also reduce the permeability of the reservoir pores and prevent water injection, and even they can degrade other oilfield chemicals and weaken the efficiency of their use of chemicals, such as degradation of the polymer used in tertiary oil recovery Oil displacement caused by the tertiary oil production ineffective. Therefore, the oil field construction of several important aspects such as drilling, oil production, oil field water treatment are involved in fungicide put, especially in China most of the oil field is the use of water injection, but also to put in order to ensure the production of water injection fungicide. According to the relevant departments, due to the corrupt role of bacteria, oilfield equipment and pipeline corrosion is very serious, and some equipment used less than a year to corrosion perforation, an oil production for one month due to pipeline congestion and forced to stop production. At present the oil field to take "three conspiracy" measures, including the put bactericide.

        At present the fungicide used in the oil field is generally used in civilian water and industrial circulatingwater treatment chemicals, such as chlorine, sodium hypochlorite, chlorine dioxide, potassium permanganate and other inorganic compounds and chlorohydrin phenols, trichloroisocyanuric acid, Ammonium salt, dithiocyanomethane, allicin and other organic compounds. These agents according to their sterilization mechanism can be divided into aerobic fungicides and non-oxygen type fungicide. As the oil field environment and water quality requirements and civil water and industrial circulating water environment and water quality requirements of different types of bacteria and their different hazards, the performance requirements of fungicides are also different. Therefore, the development and development of oilfield fungicide is a hot topic in oil field chemistry field for many years.

        The most harmful bacteria in the field are sulfate-reducing bacteria, iron bacteria and saprophytic bacteria. Therefore, the choice of fungicides to start against these bacteria. Sulfate-reducing bacteria are strictly anaerobic bacteria, anaerobic respiration, that is, oxidation of carbon-containing organic compounds or hydrogen, reducing sulfate, H2S. It exists in a wide range of pH 5.5 ~ 9.0, the field generally exist in the sulfate-reducing bacteria is Vibrio spp., Mainly in groups or colonies attached to the wall, its main hazards in the metal Surface depolarization. Due to its role in hydrogenase, the sulfate reduction to sulfide and primary oxygen state [O], and [O] and [H] to produce H2O depolarization, by its depolarization to accelerate the pipeline and equipment corrosion. The corrosion product, FeS, can also clog the pipeline and water injection wells. Sulfuric acid-reducing bacteria is the most harmful, almost from all aspects of oil production. Therefore, in recent years, people attach great importance to its research; such as the development of new strains of sulfate-reducing bacteria; the scope of its carbon-containing organic compounds. In this not a chelate. Iron bacteria is a wide distribution of multi-mouth bacteria, it is a saprophytic bacteria, mainly ferrous iron into high-priced iron, the use of iron to release the energy of oxidation to meet their survival needs. It is a good aerobic heterotrophic bacteria, and its harm is the equipment and pipes to form oxygen concentration cell Erzhi equipment and pipeline accelerated corrosion, which secrete large amounts of mucus can cause water injection wells and filter blockage, and it to the sulfate-reducing bacteria to provide survival, Reproduction environment. Saprophytic bacteria, also known as mucus forming bacteria, is aerobic heterotrophic bacteria, which secrete large amounts of mucus attached to the pipeline and equipment, resulting in biological fouling plug wells and filters, but also produce oxygen concentration cell caused by equipment and piping Of the corrosion and sulfate-reducing bacteria to provide survival, reproduction environment. 

Bacteria and other organisms, like to be subject to environmental constraints. We choose to kill bacteria Pharmacy, is based on factors that can affect growth:

        (1) hinder the cell respiration;

        (2) inhibition of protein synthesis, or damage the water membrane protein, or protein and electrons, the protein precipitation and loss of activity;

        (3) damage the balance of the environment inside and outside the body, so that the loss of water to dry and die, or filled with water expansion and death;

        (4) inhibiting nucleic acid synthesis, loss and alteration of its nucleic acid activity. In addition, we have to consider environmental factors, and some strong bactericidal agent, but not biodegradable, and some agents can kill the bacteria but it is the nutrient solution of other bacteria, which can not be used as oil field sterilization .

        In addition the geological conditions of the oil field and impurities in the water will affect the bactericidal efficacy.