Brines cementation

Magnesium is removed from brines of the Great Salt Lake in the form of magnesium chloride. This is then used to make elemental magnesium, dust suppressants, and bischofite flake. Magnesium chloride is also used in drilling mud, ion-exchange resins, oxi-chloral cements, fertilizers, and miscellaneous industrial uses. 

Cement and Concrete Concrete is an aggregate of inert reinforcing particles in an amorphous matrix of hardened cement paste. Concrete made of portland cement has limited resistance to acids and bases and will fail mechanically following absorption of crystalforming solutions such as brines and various organics. Concretes made of corrosion-resistant cements (such as calcium aluminate) can be selected for specific chemical exposures. 

An injectivity test is performed using clean, solids-free water or brine. If a low fluid loss completion fluid is in the hole, it must be displaced from the perforations before starting the injecting. This test will give an idea of the permeability of the formation to the cement filtrate. 

Similar copolymers with N-vinyl-N-methylacetamide as a comonomer have been proposed for hydraulic cement compositions [669]. The polymers consist of AMPS in an amount of 5% to 95%, vinylacrylamide in an amount of 5% to 95%, and acrylamide in an amount of 0% to 80%, all by weight. The polymers are effective at well bottom-hole temperatures ranging from 200° to 500° F and are not adversely affected by brine. Terpolymers of 30 to 90 mole-percent AMPS, 5 to 60 mole-percent of styrene, and residual acrylic acid are also suitable for well cementing operations [253]. 

Aq, Aqueous C, cementing Cb, clay based D, drilling fluids FF, fracturing fluids HP, high pressure application HT, high-temperature application LT, low temperature Ob, oil based S, seawater mud SB, salt and brine tolerant. 

Portland cement is susceptible to corrosion by CO2 and H2S. The chemical attack by CO2 is called carbonation. A microsample technique has been developed to study the CO2 corrosion in cements, because the corrosion is difficult to monitor with common test procedures [264]. This technique is also advantageous as an accelerated testing method. A polymer-modified cement has been tested in field studies [694]. The addition of silica also improves chemical resistance [146], in particular brine corrosion. 

The cement slurry is pumped down the casing and up the annular space between the casing and the formation. The spacer and drilling fluid are thus displaced by the cement slurry. A compatible fluid (one that does not substantially alter the set time of the cement slurry) is pumped into the wellbore to displace nearly all the cement slurry into the annular space between the casing and the formation. The well is then shut in to allow the cement to set. This bonds the casing to the formation and isolates oil- and gas-bearing formations from aquifers and brine-containing formations. Fluid communication between formations can adversely affect production operations or lead to contamination of potable water aquifers. 

Fig. 25.4. Oxygen and carbon stable isotopic compositions of calcite ( ) and dolomite ( ) cements from Lyons sandstone (Levandowski et al., 1973), and isotopic trends (bold arrows) predicted for dolomite cements produced by the mixing reaction shown in Figure 25.3, assuming differing CO2 fugacities (25, 50, and 100) for the Fountain brine. Fine arrows, for comparison, show isotopic trends predicted in calculations which assume (improperly) that fluid and minerals maintain isotopic equilibrium over the course of the simulation. Figure after Lee and Bethke (1996).

Leach, D. L., G. S. Plumlee, A. H. Hofstra, G. P. Landis, E. L. Rowan and J. G. Viets, 1991, Origin of late dolomite cement by C02-saturated deep basin brines evidence from the Ozark region, central United States. Geology 19, 348-351. 

In both cases, the CaCb-rich brine is thought to have evolved from the NaCI-rich brine after fluid-rock interactions in the basement. The fault zones and the breccia bodies at the base of the basins represent active drainage zones where different fluid reservoirs were connected, and thus a highly favourable location for fluid mixing. Temperature and pressure changes, combined with the effects of fluid mixing, appear to be key-factors in the main stages of quartz cementation and U deposition in both Australian and... 

Nevertheless, hydrotalcite is not a rare mineral. It has been observed earlier as a nuclear glass alteration product in MgCl brines (Abdelouas etal. 1993,1994). It is also described as an alteration mineral of slags and cements (Mascolo 1973, 1986 Mascolo Marino 1980 Faucon et al. 1996). 

Primary two-phase inclusions are only found in the ferroan-rich dull cements (Table 8.7). The fluids contained in these inclusions, as determined ffom eutectic and melting (ice) temperatures, are dilute solutions (2.9 wt % NaCl) to complex (>23 wt % NaCl) brines. Homogenization temperatures indicate maximum temperatures of fluid entrapment of 90° to 200°C. 

The diaphragm is prepared in the following way First of all an asliestos cloth is placed on the cathode and the edges of it are attached with cement to the walls of the tank A paste made from asbestos, powdered baryte and brine is spread evenly over the cloth to a depth of 5 to 10 mm. After 5 to 6 hours the electrolyzer is cautiously filled with brine. A fresh prepared diaphragm is very permeable so that only diluted caustic solution can be produced after about 15 to 20 days the permeability decreases and finally becomes constant. During this period while the diaphragm forms itself, the concentration of caustic solution increases and attains a final value of 12 to 16 per cent NaOH or 18 to 20 per cent KOH. 

A — Anode (from graphite platos), B — Diaphragm, K — Copper gauze cathode, L — Brine inlet, — Brine outlet (for saturation with salt), S — Fixing of electrode, St — Supports for diaphragm and cathode, Z — Cement lining of the frame. 

Laboratory and field testing has shown that properly formulated sulfur composites have good resistance to water, brines, and many acids (Figure 2). Acids and brines are mediums in which portland cement products often corrode severely. 

In a second set of experiments, the rate of penetration of a brine solution into a cement sample was measured as a function of soaking time. The sample, which had a w/c ratio of 0.4, was heated in an oven at 105°C for 4 days to remove all evaporable water, and then sealed on all sides except the end face which was dipped in a saturated salt solution. The resulting 1-D profiles illustrated in Fig. 20 show the progression of the 23Na front into the sample with prolonged soaking times. 

Dolomite rock cement and concrete evaporative brines. 

In other processes similar to the Solvay process (see Section 3.1.1.3.3), potassium carbonate is produced directly from potassium chloride with amines such as isopropylamine via a potassium hydrogen carbonate step, but contaminated calcium chloride brine is produced as a byproduct whose disposal poses environmental problems. In the former States of the USSR potassium carbonate is also produced from alkali aluminosilicate deposits (e.g. nepheline) together with aluminum oxide, cement and sodium carbonate. 

As a result, the permeabilities in these domains within the formation become more uniform. Reduction in permeability in the more permeable domains improves the mobility ratio of waterflood. Premature breakthrough is thus reduced, and the efficiency of the waterflood is improved (Boston et al., 1969). Poorly cemented clay particles, such as kaolinite and illite, can become detached during aqueous flow, especially when flowing brines become fresher. 

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