![]() The pressure and flow sensors are repositioned above the top of the middle layer.Finally, a continuous flow profile is recorded across the set of producing layers. The well is opened to the smallest choke opening, and the ensuing transients of rate and pressure are recorded until stabilization occurs. The well is shut in, and the pressure and flow sensors (typically conveyed by a production logging tool) are positioned above the top of the uppermost layer.The following steps describe a typical design for a three-layer multirate test: 4 – Typical design for a three-layer multirate test (PL = production logging). 2) is a straight line on the semilog plot, which in turn can be interpreted to yield the test objectives of the permeability and skin effect.įig. the "sandface convolution time" (a time function akin to a generalized superposition function). The technique used here makes use of semilog analysis, in which rate-normalized pressures are plotted vs. A constant flow-rate function was sought to interpret this test. Clearly, the pressure and flow-rate data mirror each other, which is precisely the effect of the convolution. 1 shows an example in which the transient consists of a step-rate change from a high value with a downhole spinner flowmeter rotation rate of approximately 17 revolutions per second (rps) to a lower value with a flowmeter response of approximately 7 rps. The process can be made to converge rather rapidly for a pressure measurement of a given resolution, as long as the results allow for an acceptable margin of error.įig. When software deconvolution operators are used, trial and error is required to convolve a flow-rate schedule with a pressure function that approximates the true constant rate-equivalent pressure function, thus reproducing the measured pressures. ![]() Where p D, the pressure function equivalent to a constant flow rate situation, is obtained by mathematical deconvolution of the pressure from the flow-rate fluctuations. The bottomhole pressure and flow rate are mathematically convolved (coupled) as follows: The pressure-flow convolution involves simultaneous bottomhole flow rate and pressure measurements to correct for the variations of bottomhole pressure caused by flow rate fluctuations during drawdown tests. Pressure flow convolution and deconvolution Determine hydraulic communication between wells.Evaluate workover or stimulation treatments.ĭescriptive reservoir tests are conducted to:.Obtain representative fluid samples suitable for PVT analysis. ![]() Measure reservoir pressure and temperature.Identify produced fluids and determine their respective volume ratios.Characterize formation damage and other sources of skin effect.8.3 Vertical extent of fracturing and detecting lost circulation.8.1 Recommendations for temperature profiling.8 Temperature profiles in production and injection wells.7 Using pressure to characterize reservoir fluids.5.2 Packer and multiple-probe tests for vertical interference testing.5.1 Packer probe tests: small-scale drillstem testing.2 Pressure flow convolution and deconvolution.1 Applications of pressure transient tests.This SIP file can then be used in place of individual files to collect and process data. The file name includes the system description (usually the network master serial number) and the creation date. All CAL and TDF files required for a system are zipped using winzip and the extension changed from *.ZIP to *.SIP. This can become quite confusing to keep track of all these files so Sea-Bird Scientific developed SIP files. These files must be used to both collect and process the data. A more complex example is a HPROII profiling system that may contain as many as 5 sensors and 7 individual calibration and tdf files. The simplest example is a HOCR sensor that generates both light and dark frames. In some cases, systems are created that network many sensors together and their combined data is provided in one serial output. Calibration files or *.cal files and telemetry definition format files or *.tdf files. ![]() Files that are delivered with Sea-Bird Scientific and third party equipment to describe the sensors data output and calibration coefficients come in two types.
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