Introduction to Production and Gas Processing Facilities Core

Transcription

1 Introduction to Production and Gas Processing Facilities Core Production Facilities Learning Objectives By the end of this lesson, you will be able to: State typical crude oil and produced water specifications Describe process flows for each stream in production facilities List problems associated with and strategies to deal with solids production (e.g., sand, wax, asphaltenes)

2 Crude Oil Value Chain Natural Gas Value Chain Why Is Processing Necessary? To meet sales/disposal specifications Crude oil / natural gas / NGLs Specifications are set contractually by: 1) The buyer 2) The transporter, or 3) By subsequent processing requirements Water Disposal specifications are set externally by regulatory bodies or internally by reservoir/production requirements

3 Crude Oil Specifications Water content (BS&W) Typically varies from 0.3 to 3.0 vol% May be set by salt specification Crude Oil Dehydration or Treating Wash Tanks/Settling Tanks/Gunbarrels Heater Treaters Heater Treaters: Used to heat the oil to lower its viscosity, which makes it easier for water droplets to settle out of the oil. Crude Oil Specifications Water content (BS&W) Typically varies from 0.3 to 3.0 vol% May be set by salt specification Crude Oil Dehydration or Treating Wash Tanks/Settling Tanks/Gunbarrels Heater Treaters Electrostatic Treaters Electrostatic Treaters: A high voltage electric field that causes water droplets to vibrate and collide and form larger droplets that can more easily settle out by gravity.

4 Crude Oil Specifications Vapor pressure Typically near 1 atm, e.g., 10 psia [69 kpa], 12 psia [83 kpa], etc. Can be specified as a True Vapor Pressure (TVP) or Reid Vapor Pressure (RVP) Crude Oil Stabilization Stage Separation Stage Separation: The most common way to meet a vapor pressure specification is to simply flash the oil from higher pressures to lower pressures using a series of separators. The volatile components vaporize in each separator and are removed from the oil. Crude Oil Specifications Vapor pressure Typically near 1 atm, e.g., 10 psia [69 kpa], 12 psia [83 kpa], etc. Can be specified as a True Vapor Pressure (TVP) or Reid Vapor Pressure (RVP) Crude Oil Stabilization Stage Separation Crude Oil Stabilizers Crude Oil Stabilizers: A distillation process that flashes out the volatile components by the addition of heat.

5 Crude Oil Specifications Salt Typical specification is 10 lb/1000 Bbl [30 g/m 3 ] When the salt content > 200,000 to 300,000 ppm, the BS&W of the oil leaving the last desalter stage should be 0.1% or lower Desalting Desalters (basically crude oil dehydration but salt content of water is diluted by injecting fresh water into the oil) Desalting crude oil requires two steps: 1) Dilute the salt content of the produced water by mixing fresh water into the oil stream. 2) Dehydrate the oil to a very low BS&W specification to minimize the amount of water in the oil. Crude Oil Specifications H 2 S Typical specification is 50 ppmw Don t confuse with organic sulfur H 2 S Stripping Heat and stripping gas Heat and Stripping Gas: When we talk about an H2S specification, we're not talking about organic sulfur, we're talking about soluble H2S in the crude oil. The most common way to meet the H2S specification is to heat the oil and inject sweet natural gas to strip the H2S out of the oil.

6 Produced Water Specifications Typical disposal options Onshore Reinject into reservoir or waste water aquifer Surface disposal Evaporation ponds Offshore Reinjection Disposal to sea Produced Water Specifications Hydrocarbon content Dispersed/dissolved Offshore specifications vary from mg/l Lower in inland and coastal water waters No fixed specification for reinjection set by reservoir characteristics Deoiling Skim Tanks Corrugated Plate and Parallel Plate Interceptors (CPI and PPI) Hydrocyclones Gas Flotation Units Deoiling: The process of removing hydrocarbons from the water.

7 Produced Water Specifications Solids Sand, corrosion products, scales Control of solids is very important in reinjection systems Filtration Settling tanks Several different types of flow-through filters