- المجال: Oil & gas
- Number of terms: 8814
- Number of blossaries: 0
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The lowest temperature at which application of a flame to the test chamber of a tester causes vapors of the sample in the chamber to ignite. The test can be applied to base fluids being considered for use in an oil mud or a synthetic mud or to any flammable liquid to determine at what temperature an explosion hazard exists. Test methods, established by API and ASTM, include open-cup and closed-cup tests.
Industry:Oil & gas
The lowest temperature (in °F or °C) at which a liquid remains pourable (meaning it still behaves as a fluid). Oil or synthetic muds with high pour points may suffer from poor screening and excessive pressure, surges in deepwater wells or other operations subject to low temperatures. In oils, the pour point is generally increased by a high paraffin content. The pour point of liquid additives is an important consideration for arctic drilling operations.
Industry:Oil & gas
The lower portion of the drillstring, consisting of (from the bottom up in a vertical well) the bit, bit sub, a mud motor (in certain cases), stabilizers, drill collar, heavy-weight drillpipe, jarring devices ("jars") and crossovers for various threadforms. The bottomhole assembly must provide force for the bit to break the rock (weight on bit), survive a hostile mechanical environment and provide the driller with directional control of the well. Oftentimes the assembly includes a mud motor, directional drilling and measuring equipment, measurements-while-drilling tools, logging-while-drilling tools and other specialized devices. A simple BHA consisting of a bit, various crossovers, and drill collars may be relatively inexpensive (less than $100,000 US in 1999), while a complex one may cost ten or more times that amount.
Industry:Oil & gas
The loss of water from cement slurry or drilling fluid by the process of filtration. Dehydration results in the deposition of a filter cake and loss of the slurry鈥檚 internal fluid into a porous matrix. The cement is not completely dehydrated because sufficient water remains to allow setting of the cement.
Industry:Oil & gas
The loss of drilling fluid to a formation, usually caused when the hydrostatic head pressure of the column of drilling fluid exceeds the formation pressure. This loss of fluid may be loosely classified as seepage losses, partial losses or catastrophic losses, each of which is handled differently depending on the risk to the rig and personnel and the economics of the drilling fluid and each possible solution.
Industry:Oil & gas
The location, or depth, at which drilling an interval of a particular diameter hole ceases, so that casing of a given size can be run and cemented. Establishing correct casing points is important in the design of the drilling fluid program. The casing point may be a predetermined depth, or it may be selected onsite by a pressure hunt team, selected onsite according to geological observations or dictated by problems in the openhole section. In many cases, weak or underpressure zones must be protected by casing to enable mud weight adjustments that control unstable formations or overpressure zones deeper in the wellbore.
Industry:Oil & gas
The location supervisor for the drilling contractor. The toolpusher is usually a senior, experienced individual who has worked his way up through the ranks of the drilling crew positions. His job is largely administrative, including ensuring that the rig has sufficient materials, spare parts and skilled personnel to continue efficient operations. The toolpusher also serves as a trusted advisor to many personnel on the rigsite, including the operator's representative, the company man.
Industry:Oil & gas
The liquid that passes through a filter cake from a slurry held against the filter medium, driven by differential pressure. Dynamic or static filtration can produce a filtrate.
Industry:Oil & gas
The limiting or prevention of motion of the drillstring by anything other than differential pressure sticking. Mechanical sticking can be caused by junk in the hole, wellbore geometry anomalies, cement, keyseats or a buildup of cuttings in the annulus.
Industry:Oil & gas
The length of the wellbore, as if determined by a measuring stick. This measurement differs from the true vertical depth of the well in all but vertical wells. Since the wellbore cannot be physically measured from end to end, the lengths of individual joints of drillpipe, drill collars and other drillstring elements are measured with a steel tape measure and added together. Importantly, the pipe is measured while in the derrick or laying on a pipe rack, in an untensioned, unstressed state. When the pipe is screwed together and put into the wellbore, it stretches under its own weight and that of the bottomhole assembly. Although this fact is well established, it is not taken into account when reporting the well depth. Hence, in virtually all cases, the actual wellbore is slightly deeper than the reported depth.
Industry:Oil & gas
