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60 Cards in this Set
- Front
- Back
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An IPR curve can be a straight line if
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the only produced fluid is oil
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What parameter has no effect on the inflow performance of a reservior?
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Production tubing diameter
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In analyzing performance of a production system, two pressure are considered constant. They are
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Reservoir pressure and Separator Pressure
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If the actual Q for a well is lower at a given Pressure than that predicted from its IPR curve, the reasons
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There are many factors , cannot be determined from the info given
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Which will have the largest partial completion skin assuming theta, hw, zw, h, number, length, diameter, and phasing of perforations are the same for all?
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the largest largest height
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Which perforation scheme will have the lowest perforation skin, including effects of damage, assuming rw = .328 ft and rs = 1.328?
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The deepest perforation length, the most shots per foot, and the smallest perforation radius
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A common way to attempt to decrease initial perforation damage is to
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perforate underbalanced
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On an IPR curve, what could increase the line? (aka goes from P res at 500 and Q 100 to P res 600 and Q 200)
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Artifical lift and a change in reservoir drive mechanism
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What does not change as a result of a well stimulation operation?
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Reservoir permeability
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What reservoir is a good candidate for matrix aciding and hydrualic fracturing?
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acidizing = high formation damage
fracturing = low permeability reservoir |
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When designing a matrix acidizing treatment, the following parameter does not need to be considered:
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Formation closure stress
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What well would have the smallest value for total skin? Note: Theta below is the well deviation from vertical - not perforation pahsing, all other contributions to skin plus, hw, zw, h, number, length, diameter and phaseing of the perforations are the same for all.
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The most deviated well
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The main purpose of production tubing is to
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convey produced fluids to the wellhead
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The most important purpose of a production packer is to
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provide a pressure safety barrier
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A major advantage of a cased, cemented, perforated completion over an open hole completion is that it
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allows isolation of different producing intervals
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Which of the following best describes the parameters that influence the design of a hydraulic fracture treatment?
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Formation closure stress, formation height, and formation permeability
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If the pressure drop in the wellbore is reduced while all other parameters are the same, that will result in
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increase production rate
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Which of the following parameters does not affect tubing performance:
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perforations
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To minimize precipitation of paraffins on a seafloor flow line, you would
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minimize temperature drop in the line
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Barium sulfate (BaSO4) scale
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results from fluid mixing
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The substance that can created both solids problems and acid corrosion is
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carbon dioxide
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Pigging is used to remove
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asphaltenes
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What is mineral scale?
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A scale that occurs with water presence with fluid mixing, pressure decrease, and pH increase
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What are carbonates and what do they do?
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occur with pressure drop
They release CO2, raise the pH and leaves C03 2-, acid soluble |
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Where do sulfates occur?
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Occurs with temperature drop and fluid mixing. Usually downstream of fluid mixing locations
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How do asphaltenes occur?
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When pressure drops and crude de-gases.
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How do Paraffins (wax) occur?
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when temp drops
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How do hydrates form?
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with high pressure and low temps, with water and methane (usually)
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How do you remove wax?
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Heat (Hot oil)
Scrapers Hydrualic- nozzle on coilded tubing or work string Bactiera Pig Lines |
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How do you remove asphaltenes?
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Wellbore: Aromatic solvent soak (xylenes, toluene)
Scrapers on work string Nozzle on coiled tubing or work sting Surface lines: Solvents Pigging |
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How do we remove hydrates?
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Alcohol/water mixture
Threshold inhibitors |
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How do we remove carbonates?
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HCl or milling
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How do we remove sulfides?
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HCL , but produces H2S that way
Remove with scrappers |
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How do we remove sulfates?
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CaSO4 - milled or dissolved w/ water
BaSO4 - Milling |
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What can be removed with acid?
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sulfides, carbonates,
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What can be removed with milling?
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CaSO4, BaSO4, carbontes (if large amount)
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When does acidizing created a problem?
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when you acidize sulfides, creates H2S
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What can be prevented or removed with heat?
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Waxes and sulfates
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What can be prevented or removed with an aromatic solvent?
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asphaltenes in the wellbore
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What can be prevented or removed with a squeeze (continuous injection)?
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hydrates
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What causes corrosion?
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The reaction of iron, CO2, H2S, acid stimulation, bacteria
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What is a workover?
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repair or stimulation of an existing production well for the purpose of restoring, prolonging, or enhancing the production of hyrcarbons
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Why do we do workovers?
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for data gathering
integrity monitoring of tubing, casing, and packers Well repair To improve performance (cleanout, flow assurance, stimulation, artifical lift) Change intervals connect to reservoir |
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What are different methods of re entering a well?
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Wireline, fullbore pumping of fluid chemicals, coiled tubing, through tubing
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What are the four general mechanisms of water entry into a well?
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open water zone
flow behind pipe and casing leaks channeling form injector or aquifer via fracture/fault Coning or cusping |
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What are the two majors types of polymer gel used for water and gas shut off? Where/how are they used?
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matrix penetrating gelant
How- reacts with water makes a crosslink polymer flowing gel placed will gelling into matrix to seal formation |
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What are factors that conbribute to sand production?
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prooly consolidated fomration
decrease in reservoir pressure drag forces solids buildup in wellbore erosion of tubular |
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What are the two approches to preventing sand production?
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Filters (slotted liner, wire wrapped screen, pre packed screen, stainless mesh filtration screen, expandable screen)
Gravel pack |
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What are some advantages and disadvantages to a open hole (barefoot) completion?
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Ad:
Low cost large formation contact minmium formation damage Dis: No isolation Can collaspe |
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What are some advantages and disadvantages to a open hole (liner or screen) completion?
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Ad:
low cost large foormation contact Minimum formation damage collapsing risk minizmied Dis: expensive to remediate casing set w/o knowing net pay cannot isolate |
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What are some advantages and disadvantages to a case, perforated completion?
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Ad:
Good primary cement Good zonal isolation Easily deepend Dis: Perforating is expensive Formation damage |
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What are some advantages and disadvantages to a cemented perforated liner completion?
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Ad:
less formation damage Good set up for zonal isolation, stimulation, sand control, deepening Dis: Cost smaller wellbore diameter primary cement integrity difficult |
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What does skin do to IPR?
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significantly reduces production rate for any bottom hole flowing pressure.
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What are the skin components?
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Damage skin: reduction of near wellbore permeability
Completion skin: partial penetration and well deviation Perforation skin: wellbore and converging effect Phase-effect and rate-dependet skin: phase change and turbulence damage |
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Where does skin come from?
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Drilling (invasion by fluid particles and filtrate)
Completion (invasion of fluids, cementing, perforationg, and stimulation) Production (fines migration and precipitation) Inejection (solid particles, precipitation, and bacteria growth) |
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What is IPR?
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inflow performance relationship
It determins completion type and optimization and production enhancement selection. Production rate from reservoir for a given bottom hole pressure |
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Total pressure drop in a well comes from what?
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Hydrostatic head (largest for an oil well)
Friction (largest for a gas well) |
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What are the four flow regimes in vertical wells?
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Bubble (some small bubbles)
Slug (large bubbles every once in awhile) Churn ( constant large bubbles) Annular (gas in the middle oil at the wall) |
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What are the seven flow regimes in horiztonal wells?
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stratifed (two layers)
wavy (liquid makes waves) annular (gas in middle, liquid on walls) plug (gas bubbles varying) slug ( large gas bubble in liquid) bubble ( bubbles in liquid) mist ( liquid in gas) |
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What is nodal analysis?
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The overlay of VLP and IPR to find flowing pressure and flowrate.
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