INFLOW PERFORMANCE The rate of fluid flow through rock depends on the following variables: pressure gradients, fluid saturation, fluid viscosities, and rock properties, the most important of which is permeability. • Plot between bottomhole flowing pressure (Pwf), versus the flow rate, q, is referred as inflow performance relationship or IPR. • Inflow performance of the well represents its ability to give up fluids. • This ability depends on the following factors: Types of Reservoir Drive mechanism Reservoir Pressure Permeability This equation states that liquid inflow into a well is directly proportional to the pressure drawdown. It will plot as a straight line on a pressure vs. rate diagram. Well’s PI can be measured by taking flow rates at various FBHPs. This works well for a single phase flow, but when producing from a multiphase reservoir the curve will not plot as a straight line. IPR Curve Reservoir pressure will generally be depleted by production, the IPR, over the life of a well, may be shown by a family of curves. Each curve represents the pressure-rate relationship at a given average reservoir pressure. A mathematical tool used in production engineering to assess the performance of the completion string by plotting the surface production rate against the flowing bottomhole pressure. The fluid composition and behavior of the fluid phases in the specific completion design will determine the shape of the curve. The TPC (tubing performance curve) is used with the inflow performance relationship to predict the performance of a specific well. Schlumberer Artificial Lift Systems? After a well has been drilled and completed, it will be flowed back using the natural pressure of the well. At some point the natural pressure will fall off and/or the well will load up with fluid and kill itself. Hence, needs artificial lifting process to fetch the fluid in the well. AL includes rod lift, gas lift, ESP, plunger lift, hydraulic progressive cavity pump etc. Sucker Rod Pump Pump-Assisted Lift – ESP An electric submersible pumping (ESP) assembly consists of a downhole centrifugal pump driven by a submersible electric motor, which is connected to a power source at the surface Pump-Assisted Lift – PCP As the rotor turns, cavities between the rotor and stator move upward. Progressive cavity pumps are commonly used for dewatering coalbed methane gas wells, for production and injection applications in waterflood projects and for producing heavy or high-solids oil. They are versatile, generally very efficient, and excellent for handling fluids with high solids content. However, because of the torsional stresses placed on rod strings and temperature limitations on the stator elastomers, they are not used in deeper wells. Gas Lift There are two main types of gas lift: Continuous gas lift, where gas is injected in a constant, uninterrupted stream. This lowers the overall density of the fluid column and reduces the hydrostatic component of the flowing bottomhole pressure. This method is generally applied to wells with high productivity indexes. Intermittent gas lift, which is designed for lower-productivity wells. In this type of gas lift installation, a volume of formation fluid accumulates inside the production tubing. A high-pressure “slug” of gas is then injected below the liquid, physically displacing it to the surface. As soon as the fluid is produced, gas injection is interrupted, and the cycle of liquid accumulation-gas injectionliquid production is repeated. Transportation of Hydrocarbons • Midstream operations are designed to transport hydrocarbons from upstream production operations to downstream refining and processing operations. • Many modes of transportation are used to transport oil and gas. • They include pipelines, tanker trucks and ships, and trains. • The mode of transport depends on such factors as safety, distance, and state of the fluid. • Pipelines are often the first choice for transportation. • Laying pipelines is a construction project that requires specialized heavy equipment, as shown in Figure. • Pipelines that transport fluids over long distances usually need compressor stations or pump stations to keep fluids moving. • The number and location of compressor stations and pump stations depends on distance travelled and terrain. • Maintenance is needed to prevent pipeline leaks. Pipelines can leak if they crack or burst. Hydrocarbon leaks are harmful to the environment and can impact community support for the pipeline. • • Pistonlike scrubbing devices called “pigs” are run through pipelines to displace liquid phases to exit points along the pipeline route. • Pipeline pigs are driven by the flow of fluids in the pipeline. They remove unwanted debris such as water and residual wax inside the pipeline. • Intelligent pigs contain sensors that can be used to inspect the internal pipeline walls and identify possible problems such as corrosion. • Other oil and gas transportation modes include trucks, trains, barges, and tankers • It is often necessary to provide facilities that gather and store fluids at the upstream site and provide storage facilities at the downstream site. • This requires gathering and processing operations, as well as terminal developers and operators. • Processing begins at the well site where the produced wellstream is separated into oil, water, and gas phases. • Further processing at natural gas plants and oil refineries such as the refinery shown in Figure separates the hydrocarbon fluid into marketable products. • An oil refinery converts a typical barrel of crude oil into gasoline, diesel, jet fuel, liquefied petroleum gas (LPG), heavy fuel oil, and other products. Colour Viscosity (thickness) Flammability Light fraction, with low small boiling point range colourless thin, runny liquid ignites easily (burns with clean flame) Medium fraction, with midmedium range boiling point yellow thicker liquid more difficult to ignite (some smoke in flame) dark orange viscous (thick) liquid Fraction Size of molecules Heavier fraction, with large higher boilng points difficult to ignite (burns with smoky flame)
