- 行业: Oil & gas
- Number of terms: 8814
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A specific gravity scale developed by the American Petroleum Institute (API) for measuring the relative density of various petroleum liquids, expressed in degrees. API gravity is gradated in degrees on a hydrometer instrument and was designed so that most values would fall between 10掳 and 70掳 API gravity. The arbitrary formula used to obtain this effect is: API gravity = (141. 5/SG at 60掳F) - 131. 5, where SG is the specific gravity of the fluid.
Industry:Oil & gas
A specially prepared fluid used to displace matrix acid treatments away from the wellbore at the conclusion of a stimulation treatment. The overflush is typically formulated from a weak acid solution or brine to maintain a low pH environment in the near-wellbore formation that prevents the precipitation of reaction products as the treatment fluids are flowed back. <br><br>The overflush is normally a weak acid or brine pumped behind the main treating fluid (mixture of hydrofluoric (HF) and hydrochloric (HCl) or organic acids). <br>The overflush has several purposes:<br>路 displacement of the nonreacted mud acid into the formation. <br>路 displacement of mud-acid reaction by-products such as amorphous silica. The minimum overflush volume should have at least 3 ft (1 m) of radial penetration inside the formation to displace potential problems away from the critical matrix. <br>路 removal of potential oil-wet relative-permeability problems caused by some corrosion inhibitors.
Industry:Oil & gas
A specially prepared fluid placed in the wellbore over the interval to be perforated. The ideal fluid is clean and solids-free (filtered), and will not react to cause damaging by-products on contact with the reservoir formation. Perforating in a dirty fluid may result in significant permeability damage that is difficult to treat and remove.
Industry:Oil & gas
A specially formulated material used for completion components in wells likely to present corrosion problems. Corrosion-resistant alloys can be formulated for a wide range of aggressive wellbore conditions. However, cost generally determines the viability of any particular completion design. Alloys with a high chrome content are commonly used for tubing strings.
Industry:Oil & gas
A specially designed packer assembly used in conjunction with a tie-back liner. The tie-back packer can be integral to the original liner hanger, or if the tie-back is a remedial treatment, it can be a separate component set above the liner hanger.
Industry:Oil & gas
A specialized perforating-gun system that contains shaped charges loaded at 0掳, 60掳, 120掳, or 180掳 phase angles to provide a casing entrance hole of approximately 0. 5 in. (1. 3 cm), which is intended to be large enough for hydraulic fracturing operations.
Industry:Oil & gas
A specialized tool, frequently used in gravel-pack operations, that enables the circulation of the treatment fluid (slurry) from the internal flow path of the tool string into the annulus area to be packed. The returned carrier fluid enters the internal flow path at the base of the tool before crossing over to the annulus above the packer assembly, isolating the annulus.
Industry:Oil & gas
A special section of cable that is placed between the logging cable and the head of the logging tool. Unlike the logging cable, the steel load-bearing element is in the center, surrounded by the conductors that are held in an insulating jacket. The bridle is needed for most conventional electrical logs and laterologs in which the cable armor is used as a current return. To be effective, this return must be at some distance from the logging tool and insulated from it. Typical bridles are 80 ft (24 m) long. Electrodes may be wound on the outside of the bridle and connected to the logging tool for use as measurement references or for spontaneous potential measurements.
Industry:Oil & gas
A special perforating gun, or charge, that is designed for limited penetration to allow an inner tubing or casing string to be perforated without damaging a surrounding outer string. These guns often are used in remedial or workover operations in which downhole communication devices, such as sliding sleeves, cannot be opened to allow circulation of well-kill fluids.
Industry:Oil & gas
A special mathematical geometry with properties that reproduce a pattern over a range of scales. They can contain some variations so that the patterns do not perfectly repeat. This geometry claims to represent many natural systems, including plant growth, geological deposition, coastlines and other geographical shapes. Fractal geometry has also led to the recent study of "Chaos Theory. " This technology is sometimes used in geostatistical studies. <br><br>Reference:<br><br>Mandelbrot BB: The fractal geometry of nature. New York, Freeman, 1983. <br><br>Hewett TA: "Fractal Methods for Fracture Characterization," in Yarus JM and Chambers RL (eds): 鈥淪tochastic Modeling and Geostatistics,鈥?AAPG Computer Applications in Geology, no. 3. AAPG, Tulsa, Oklahoma, USA, 1994.
Industry:Oil & gas
