- 産業: Oil & gas
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A condition in deviated wellbores in which an additional friction component is applied as the slickline, wireline or coiled tubing is drawn to the inside radius of the curve. The effect is largely dependent on the load on the string, with the resultant friction forces being of most influence when high loads are encountered under static or slow-moving conditions.
Industry:Oil & gas
A condition encountered during some hydraulic fracturing operations whereby the fracture cannot accept further sand or proppant and only the carrier fluid is injected into the formation. A sandout occurs when the concentration of proppant within the tubing string rapidly increases, creating a corresponding sudden increase in pump pressure.
Industry:Oil & gas
A condition caused by an increase in water saturation in the near-wellbore area. Water block typically forms during the drilling phase of a well, when the near-wellbore area is exposed to a relatively high volume of filtrate from the drilling fluid. The increased presence of water causes fine clay crystals that may be present in the formation, such as illite, to swell and cause a reduction in permeability. Water-block treatments typically use surfactants to reduce the surface tension between the oil and water, helping to displace the water from the near-wellbore area.
Industry:Oil & gas
A condition affecting an operating pump whereby the pump space is not fully charged with fluid being pumped. Pump cavitation may result from inadequate or restricted supply or from the introduction of air or gas into the fluid stream. The effect of cavitation depends on the type of pump. However, in most cases, it is an undesirable condition that causes a reduction in pump efficiency and excessive wear or damage to pump components.
Industry:Oil & gas
A condensate (liquid hydrocarbon) produced at surface from cycle gas.
Industry:Oil & gas
A concept for advanced computer calculations developed by Alan Turing to mimic some of the operations of the neurons in a brain. Memory elements (neurons) are conceptually interconnected by multiple paths connected with on-off switches to emulate the synapses of the brain. The original intent was to build a data-processing machine. <br>Modern applications reduce the concept to structured digital software processing models. Repeated processing through a neural network allows the network to learn from the data it processes. The learned process obtained from a set of training data with solutions can then be applied to other data sets for which no solution exists. An oilfield example includes training a network with wireline log and core data and then using the network to interpret further log data in terms of the core data. Neural networks are also being used in seismic processing, geological mapping and petrophysical analysis.
Industry:Oil & gas
A computer system that uses a rule-based algorithm to provide expertise on a given subject. Many computer programs have been written for use in the oil field using rule-based approaches to provide expert systems. The rules are taken from an expert working in the field and are written in a way that attempts to reproduce the knowledge and approaches used by that expert to solve a range of actual problems. Most such programs are limited to specific disciplines such as dipmeter interpretation, electrofacies determination, reservoir characterization, blowout prevention or drilling fluid selection. Sometimes expert systems are written in computer languages such as LISP that easily handles rules, but once fully tested, expert systems are usually translated to BASIC, C or FORTRAN to be compiled into efficient applications or programs.
Industry:Oil & gas
A computational procedure incorporated in methods for determining the values to be assigned to grid elements on a map. The deterministic gridding algorithms are mostly simpler interpolation; the stochastic approaches include the geostatistical methods, among them kriging.
Industry:Oil & gas
A computer run of a reservoir model over time to examine the flow of fluid within the reservoir and from the reservoir. Reservoir simulators are built on reservoir models that include the petrophysical characteristics required to understand the behavior of the fluids over time. Usually, the simulator is calibrated using historic pressure and production data in a process referred to as "history matching. " Once the simulator has been successfully calibrated, it is used to predict future reservoir production under a series of potential scenarios, such as drilling new wells, injecting various fluids or stimulation.
Industry:Oil & gas
A device for measuring the internal diameter of a casing, tubing or open borehole using high-frequency acoustic signals. A transducer (in transmit mode) emits a high-frequency pulse that is reflected by the pipe or borehole wall back to the transducer (in receive mode). The diameter is determined from the time of flight of this echo and the fluid acoustic velocity. The transducer is rotated to produce a cross section of the borehole size and full-coverage images of the borehole wall. The measurement has high resolution and is used to detect deformations, the buildup of scale, or metal loss due to corrosion. <br>The amplitude of the echo from the inner casing surface provides qualitative information on the state of the surface, such as rugosity or corrosion. Casing thickness may also be measured simultaneously, either by analysis of the casing resonance signal, or by detecting separately the echoes from the inner and outer casing surfaces.
Industry:Oil & gas
