We must comment a bit about gas lift systems because they are in widespread use and have a significant impact on the facility process. Figure 2-19 is a diagram of a gas lift system from the facility engineer’s perspective. High-pressure gas is injected into the well to lighten the column of fluid and allow the …
Read More…Category: Basic Configuration
Well Testing
It is necessary to keep track of the gas, oil, and water production from each well to be able to manage the reserves properly, evaluate where further reserve potential may be found, and diagnose well problems as quickly as possible. Proper allocation of income also requires knowledge of daily production rates as the royalty or …
Read More…Gas Dehydrator
Removing most of the water vapor from the gas is required by most gas sales contracts, because it prevents hydrates from forming when the gas is cooled in the transmission and distribution systems and prevents water vapor from condensing and creating a corrosion problem. Dehydration also increases line capacity marginally. Most sales contracts in the …
Read More…Compressors
Figure 2-14 shows the configuration of the typical three-stage reciprocating compressor in our example flowsheet. Gas from the FWKO enters the first-stage suction scrubber. Any liquids that may have come through the line are separated at this point and the gas flows to the first stage. Compression heats the gas, so there is a cooler …
Read More…Water Treatment
Water Treatment describes choosing a process for this subsystem, including vessel and open drains. Figure 2-13 shows an enlargement of the watertreating system for the example.
Read More…Pumps
Pumps are normally needed to move oil through the LACT unit and deliver it at pressure to a pipeline downstream of the unit. Pumps are sometimes used in water treating and disposal processes. In addition, many small pumps may be required for pumping skimmed oil to higher pressure vessels for treating, glycol heat medium and …
Read More…Lease Automatic Custudy Transfer
In large facilities oil is typically sold through a LACT unit, which is designed to meet API Standards and whatever additional measuring and sampling standards are required by the crude purchaser. The value received for the crude will typically depend on its gravity, BS+W content, and volume. Therefore, the LACT unit must not only measure …
Read More…Oil Treating
Most oil treating on offshore facilities is done in vertical or horizontal treaters, such as those described in “Crude Oil Treating System“. Figure 2-8 is an enlargement of the oil treater in Flow Sheet. In this case, a gas blanket is provided to assure that there is always enough pressure in the treater so the …
Read More…Process Flowsheet
Figure 2-7 is an enlargement of the FWKO of Figure 2-1 to show the amount of detail that would be expected on a process flowsheet. A flash calculation is needed to determine the amount of gas and liquid that each separator must handle. In the example process of Figure 2-1, the treater is not considered …
Read More…Two Phase vs Three Phase Separator
In our example process the high- and intermediate-stage separators are two-phase, while the low-pressure separator is three-phase. This is calleda “free water knockout” (FWKO) because it is designed to separate the free water from the oil and emulsion, as well as separate gas from liquid. The choice depends on the expected flowing characteristics of the …
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