Weighting agents barite

Production and Consumption. About 80% of the world s barite production is used as a weighting agent for the muds ckculated in rotary drilling of oil and gas wells (see PETROLEUM, DRILLING FLUIDS AND OTHER OIL RECOVERY CHEMICALS). Table 2 shows the U.S. production—consumption balance. The 1988 demand for barite increased nearly 40% over that recorded in 1987. However, by the end of 1988, oil prices had declined and renewed economic uncertainties depressed exploration and development activity. Barite demand fell accordingly and imports of lower cost foreign product exceeded domestic production. 

Solids can be classified as those required for drilling and those detrimental to the drilling operation. Required solids are viscosifers (bentonite), filtration control agents, and weighting materials (barite). Viscosifers and filtration control agents are usually colloidal in size, i.e., smaller than 2 pm—Table 4-56 [29]. 

Weighting agents (Table 10-10) are added to increase the density of the cement. They are typically used to combat high bottom-hole pressures. Common additives are powdered iron, ferromat, powdered magnetite, and barite. Hematite ean be used to increase the density of a mixture up to 2200 kg/m (19 Ib/gal). Hematite requires the addition of some water. 

Drilling fluid additives Many of the additives used in the past for drilling fluids have contained potential contaminants of concern, such as chromium in lignosulfonates. Also, barite weighting agents may contain concentrations of heavy metals such as cadmium or mercury. The use of such additives has diminished. However, it is important to select additives that are less toxic and... 

Compounds of barium, especially barite (BaS04), are critical to the petroleum industry. Barite is used as a weighting agent in drilling new oil wells. A weighting agent is a matetial that adds body to petroleum. 

Water-Based Drilling Fluids. Water-based drilling fluids consist essentially of either a freshwater- or seawater-based fluid with a weighting agent (usually barite), bentonite clay and several water-soluble polymers, together with added salts (commonly NaCl, KCl) and sodium or potassium hydroxide for pH control. 

Solid Phases. The commonest weighting agent is barite, which, in its pure form, has a density of 4500 kg/m3. The American Petroleum Institute (API) specification (12) for the density of barite is that it must be at least 4200 kg/m3. Other API specifications are the soluble alkaline metal concentrations must not exceed 250 ppm and a maximum of only 3 wt% of the barite must have a particle size in excess of 75 pm with a maximum of 30 wt% having a particle size of less than 6 m. Other suspended weighting agents are calcium carbonate and iron oxide [hematite (12)], although iron oxide is not often used due to its abrasiveness. 

Weighting agents, such as hematite or barite, to adjust the fluid density. 

Weighting agents these materials are used to control formation pressures, check formation caving, and facilitate pulling dry pipe. They included barite, iron oxides, and calcium carbonate. 

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