Advantages of using Barite in drilling mud
Drilling in high pressure wells is very challenging due to the need for formulation and precise design of drilling mud. One of the advantages of using Barite in drilling mud is the ability to increase the final weight of the mud. Typically, various weighting agents such as Hematite, Calcium Carbonate and Micromax are used in drilling operations. Barite increases the hydrostatic pressure of the drilling mud and thus controls the high-pressure areas under operation. It can be used in drilling deep wells to carry cuttings to the surface.
No abrasion
Barite powder does not wear pipes and drilling bits due to its softness. The high weight of drilling fluids increases the pressure on pipes and drilling bit, in this case hard minerals can cause more abrasion in drilling pipes.
Barite also acts as a lubricant due to its softness. By improving the flow of drilling fluid, it causes lubrication and cooling of the bit.
Neutral properties
Barite does not react with other chemicals used in drilling mud due to its neutrality. furthermore, because of not being corrosive, it does not damage pipes and drilling equipment.
Magnetic properties
Due to non-magnetic properties, it does not interfere with magnetic measurements made in deep wells.
Reasonable price
The reasonable price of Barite compared to other weighting fluids has increased its popularity. Increasing the demand along with its compatible properties compared to similar materials has led to an increase in the price of this mineral, but still the price is reasonable.
Barite specification for drilling
The American Petroleum Institute (API) has defined the Barite specification used in drilling industry. These characteristics mainly take into account the relative density, particle size and maximum amount of impurities. Barite should have a relative density of 4.2 grams per cubic centimeter and should be crushed into a powder with at least 97% passing through a 200-mesh sieve. The amount of alkaline earth metals soluble in water should be less than the recommended amount of 250 mg / kg. In addition to the specifications set by the American Petroleum Institute, the Barite used in the offshore drilling rig must also meet the mercury and cadmium content of environmental regulations.
In which type of drilling mud Barite can be used?
To perform drilling operations in deep wells various types of drilling fluids are used accordingly. Drilling muds are usually divided into two categories; water-based muds and oil-based muds. Water-based muds contain clay, weighting agents and specialty chemicals in an aqueous phase. Oil-based muds, on the other hand, contain a hydrocarbon phase and a brine phase with clay along with weighting agents. Barite can be used in both water and oil-based muds.
Reduction of Barite reserves and its compensation solution
High consumption of Barite in various industries, especially drilling, has reduced its reserves. The main reason behind the high consumption of Barite is due to its low cost and compatible characteristics in drilling. One of the solutions proposed to compensate for the reduction of Barite reserves, has been the implementation of new standards set by API. In the new standards of API 13A, the specific gravity of Barite for use in drilling has changed from 4.2sg to 4.1sg. This standard recommends that contractors use this type of Barite to increase the weight of drilling fluids. The difference between this type of Barite and conventional Barite is in reducing the percentage of purity. Since this decrease in purity of the drilling mud rheology does not change, it can also be used in drilling. By using Barite with a lower percentage of purity and lower specific gravity, it is hoped that Barite reserves will decrease at a slower rate.
Due to the fact that more than 90% of Barite is used in drilling, after drilling operations, a significant amount of Barite along with drilling logs and other fluids is generated as waste. The amount of Barite consumption in different wells depends on factors such as well depth, formation pressure/temperature, and the amount of drilling fluids consumed.
The presence of Barite in drilling mud has created waste which needs to undergo costly crushing operations, and so it can sometimes be economically viable to recover this material from drilling waste.
Environmental issues of Barite consumption
Pure Barite has a specific gravity of 4.5sg but in industrial applications weight of 4.2sg is used. This low specific gravity is due to the presence of impurities in the Barite ore. These impurities include Mercury and Cadmium. Therefore, the issue of Barite-containing waste recovery is important from two aspects; the preventing of the reduction of Barite reserves, the need to find new resources, as well as the reducing environmental issue.