- Industry: Oil & gas
- Number of terms: 8814
- Number of blossaries: 0
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A core that has been preserved in the same state as when it was brought to the surface. The term implies that the core has been stored for a period before analysis. If this has not been the case, it is known as fresh core. The goal of preservation is to maintain the original fluid content, fluid distribution, rock wettability and mechanical integrity. Preserved cores are typically sealed and protected from mechanical damage. Depending on the core and the objective, they may also be frozen or placed in humidity ovens. <br><br>Preservation may be wet, in which the core is submerged in a suitably prepared brine, or dry, without any fluid.
Industry:Oil & gas
A core that has been cleaned but then flushed with reservoir fluids to reestablish the in situ condition of the rock. The main purpose of a restored state core is to measure the wettability and related properties such as relative permeability.
Industry:Oil & gas
A core taken so as to preserve the in-situ water saturation of the rock. A native-state core is usually drilled with oil-base mud or crude oil from the same reservoir.
Industry:Oil & gas
A core taken from the side of the borehole, usually by a wireline tool. Sidewall cores may be taken using percussion or mechanical drilling. Percussion cores are taken by firing hollow bullets into the formation. The bullets are attached to the tool by fasteners, and are retrieved, along with the core inside, by pulling up the tool and the fasteners. Percussion coring tools typically hold 20 to 30 bullets, but two or three tools can be combined on one run in the hole. Mechanical tools use hollow rotary drills to cut and then pull out core plugs. Up to 75 plugs can be recovered on one run. With full recovery, cores from typical percussion tools are 1 in. (2. 5 cm) in diameter by 1 3/4 in. (4. 4 cm) long, while those from mechanical tools are 0. 91 in. (2. 3 cm) in diameter by 2 in. (5 cm) long. The latter are also known as rotary sidewall cores.
Industry:Oil & gas
A cord containing high-explosive material sheathed in a flexible outer case, which is used to connect the detonator to the main high explosive. This provides an extremely rapid initiation sequence that can be used to fire several charges simultaneously.
Industry:Oil & gas
A conventional method of mapping reservoir parameters in two dimensions, x and y. The resulting map set usually includes the top and bottom structure map derived from seismic and well data and that are used to generate thickness maps, in addition to maps of other geological and petrophysical parameters produced by standard interpolation techniques. These techniques are appropriate for describing reservoirs that are reasonably continuous and not too heterogeneous. They are usually much faster than full 3D techniques or geostatistical methods, but may be inaccurate when applied to description of complex, heterogeneous strata.
Industry:Oil & gas
A conventional electrical log with very long electrode spacing. The ultralong-spaced electrical log (ULSEL) is a normal device with a distance between the current-emitting electrode and the measure electrode of between about 75 ft (23 m) and 1000 ft (305 m). The long spacings are designed to locate objects within tens of feet of the borehole. These objects may be a salt dome or casing, in the case of a relief well.
Industry:Oil & gas
A contractual agreement with an owner who holds a working interest in an oil and gas lease to assign all or part of that interest to another party in exchange for fulfilling contractually specified conditions. The farmout agreement often stipulates that the other party must drill a well to a certain depth, at a specified location, within a certain time frame; furthermore, the well typically must be completed as a commercial producer to earn an assignment. The assignor of the interest usually reserves a specified overriding royalty interest, with the option to convert the overriding royalty interest to a specified working interest upon payout of drilling and production expenses, otherwise known as a back-in after payout (BIAPO).
Industry:Oil & gas
A contract between mineral owner, otherwise known as the lessor and a company or working interest owner, otherwise known as the lessee in which the lessor grants the lessee the right to explore, drill and produce oil, gas and other minerals for a specified primary term and as long thereafter as oil, gas or other minerals are being produced in paying quantities. This lease gives the lessee a working interest. The oil and gas lease is granted in exchange for royalty payments to the lessor.
Industry:Oil & gas
A contract between a host country and an operator that specifies the services and costs of services that the operator must use in the development of a concession.
Industry:Oil & gas
