Drilling fluids advantages

Foam Systems. The preparation, composition, and maintenance of foam completion and workover fluids is similar to that of foam drilling fluids. The advantage of foam is the combination of low density and high lifting capacity at moderate flow rates. The use of foam as a completion fluid can be justified by. 

Waste HBr is a common byproduct of organic brominations. Frequently, this waste is neutralized with caustic, the resulting sodium bromide salt is discharged, and valuable bromine is lost. The economic advantages of recovery and recycle of this HBr have long been recognized (refs. 1, 3). In practice, recovery typically takes the form of conversion of the HBr to clear drilling fluids or alkylbromides (ref. 4) as shown in equations 1 and 2. 

A formulation consisting of 2-acrylamido-2-methylpropane sulfonic acid, acrylamide, and itaconic acid has been proposed [676]. Such polymers are used as fluid loss control additives for aqueous drilling fluids and are advantageous when used with lime- or gypsum-based drilling muds containing soluble calcium ions. 

Copolymers of mainly acrylic acid and 2% to 20% by weight of itaconic acid are described as fluid loss additives for aqueous drilling fluids [138]. The polymers have an average molecular weight between 100,000 and 500,000 Dalton and are water dispersible. The polymers are advantageous when used with muds containing soluble calcium and muds containing chloride ions, such as seawater muds. 

Foam Blast 431 Foam Blast 432 antifoam, drilling fluids Triisobutyl phosphate antifoam, drilling muds Advantage 357 Defoamei AF 10 IND AF 8805 AF 8810 AF GN-11-P Antifoam E6 Polydimethylsiloxane antifoam, dripless candles Behenamide... 

Hydroxyethyl cellulose (HEC), a nonionic thickening agent, is prepared from alkali cellulose and ethylene oxide in the presence of isopropyl alcohol (46). HEC is used in drilling muds, but more commonly in completion fluids where its acid-degradable nature is advantageous. Magnesium oxide stabilizes the viscosity-building action of HEC in salt brines up to 135°C (47). HEC concentrations are ca 0.6—6 kg/m (0.2—21b/bbl). 

Tube holes cannot be drilled very close together, since this may struc-tually weaken the tube sheet. The shortest distance between two adjacent tube holes is called the clearance. Tubes are laid out in either square or triangular patterns as shown in Figure S-.i. The advantage of square pitch is that the tubes are accessible for external cleaning and cause a lower pressure drop when shell-side fluid flows perpendicularly to the tube axis. The tube pitch is the shortest center-to-center distance between adjacent tubes. The common pitches tor square putienis arc i-in. OD on... 

Chemically enhanced drilling offers substantial advantages over conventional methods in carbonate reservoirs. Coiled tubing provides the perfect conduit for chemical fluids that can accelerate the drilling process and provide stimulation while drilling [1471]. The nature of the chemical fluids is mainly acid that dissolves or disintegrates the carbonate rock. 

Solutions of TKPP have been shown to have unique and advantageous properties for use in formulating a wide variety of well fluids. Its reasonable cost, worldwide availability, and nontoxic properties make it a preferred additive for use in many petroleum applications. It has been shown to be a most effective salt with respect to inhibiting hydration and swelling of clay minerals commonly encountered in drilling operations and/or reservoirs. Avoiding clay problems is the major impetus for the incorporation of potassium ions in well fluids, and the use of TKPP provides advantages over and above those available from other potassium salts. 

The most widely used synthetic and natural enhanced oil recovery polymers, such as partially hydrolyzed polyacrylamide, carboxymethyl(ethyl) cellulose, polysaccharides, or xanthan gums, are not suitable for high-temperature reservoirs (> 90 °C) with high-density brine fluid due to excessive hydrolysis and precipitation [277]. The main advantages of polymeric betaines over the mentioned standard polymers are (1) thermostability (up to 120 °C) (2) brine compatibility and (3) viscosification in brine solution [278]. Carbobetaines grafted onto hydroxyethyl cellulose were tested as a drilling-mud additive for clay hydration inhibition and mud rheological control [279]. An increase in the content of carbobetaine moieties resulted in an enhanced inhibitive abiUty, especially for sahne mud. 

Shepherd Chenery (1995) pioneered the laser ablation ICP-MS (inductively coupled plasma-mass spectrometry) method of analyzing individual fluid inclusions. An UV laser ablation microprobe is used to drill a hole into a mineral, to reach an inclusion up to 60/zm below the sample surface. For the laser ablation procedure the sample is placed in a modified thermal vacuum cell. The elevated temperature in the ablation cell raises the internal vapor pressure of the inclusion, which causes instantaneous rupture and highly efficient fluid expulsion as the beam breaches the inclusion wall. The vacuum pulls the vaporized fluid into the ICP-MS, where it is analyzed for major and minor ion concentrations. The advantages of the ICP-MS method are the small spot size of the laser (<2 m), allows analysis of small inclusions (> 10/zm) in a variety of minerals (halite, calcite, quartz, and others). A wide range of ions can be analyzed simultaneously, including low concentrations of minor ions. With multicollector ICP-MS, it will be possible to analyze strontium isotopes and other stable isotopes (5 C, S 0, S S) in fluid inclusions. Laser ablation ICP-MS is not as precise as other methods ( 30%) and the results can only be reported as ionic ratios as the volume of an inclusion cannot be determined prior to analysis. However, if the concentration... 

The cross-injector enables analyses with microfabricated systems an order of magnitude faster than capillary-based systems. This advantage is due to the extremely small sample zones that can be injected (<1 nL) with the cross-injector, but the consequence of these minute zones is that the cross-injector is extremely inefficient. Samples are typically pipetted at 1-2 p,L volumes into the drilled reservoirs on a microdevice. Even when considering large injected sample plugs of 1 nL and a low-volume, pipetted sample (1 p.L), the cross-injector is only 0.1% efficient. That is, despite the excellent low-volume fluid-handling promises of microsystems, they still require input volumes... 

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