Alabama Oil and Gas Fields Contractor Examination

Which API standard primarily governs welded steel tanks used for atmospheric oil storage?

• AAPI 620
• BAPI 650
• CAPI 1104
• DAPI 5L

API 620 tanks are designed primarily for which service condition?

• AAtmospheric open-top stock tanks only
• BLow internal pressure up to about 15 psig in the gas or vapor space
• CHigh-pressure process vessels above 1,000 psig
• DBuried concrete septic tanks

What is the typical purpose of an annular bottom plate ring on a large API 650 tank?

• ATo provide a thicker, tougher plate ring under the shell where shell-to-bottom stresses a…
• BTo act as a permanent scaffold for painters
• CTo replace the need for a foundation
• DTo vent vapor from the roof

Why are many large crude oil tanks built with external floating roofs?

• ATo increase storage pressure above 100 psig
• BTo reduce vapor space and evaporative hydrocarbon losses while limiting fire risk
• CTo eliminate all foundation requirements
• DTo allow the tank to be buried underground

During field erection of an API 650 tank shell, which welding sequence practice best controls shell out-of-roundness and residual stress?

• AWeld only vertical seams and leave all horizontal seams open permanently
• BUse a planned sequence of vertical and horizontal shell seams with fit-up control and pro…
• CSkip fit-up and rely only on final hydrotest to reshape the shell
• DWeld the entire tank from the top course downward with no intermediate checks

What is the main purpose of sloping a tank bottom toward a sump or low point?

• ATo increase vapor pressure in the roof space
• BTo promote complete drainage and removal of water or product for cleaning and inspection
• CTo eliminate the need for cathodic protection
• DTo allow the tank to float during floods

Before backfilling a newly coated steel pipeline, what non-destructive check is commonly used to find pinholes or bare spots in the coating?

• AHoliday (spark or wet-sponge) detection
• BBrinell hardness testing of the coating
• CMagnetic particle testing of the soil
• DDye penetrant testing of the backfill sand

In pipeline construction, what is “stringing”?

• AHydrostatic testing of the completed line
• BLaying individual pipe joints along the right-of-way in sequence for welding
• CApplying final paint to the pump station
• DInstalling cathodic protection rectifiers only

Why is selected padding or fine bedding material placed under and around coated pipe before general backfill?

• ATo increase pipe temperature during hydrotest
• BTo protect the coating from rocks and sharp objects that could create holidays after lowe…
• CTo replace the need for welding inspection
• DTo make the trench narrower than the pipe diameter

What is the primary purpose of a hydrostatic test on a newly constructed pipeline segment?

• ATo measure coating color uniformity
• BTo prove pressure integrity by holding the line at a specified test pressure with water (…
• CTo cure the external coating chemically
• DTo magnetize the pipe for later location

Field girth welds on transmission pipelines are most commonly inspected for volumetric defects using which method when radiographic examination is specified?

• AOnly visual inspection of paint
• BRadiographic testing (RT) or an approved alternative such as ultrasonic testing when perm…
• CSoil resistivity survey
• DHoliday detection of the mill coating only

What is the main function of a tank dike or secondary containment berm around oil field storage tanks?

• ATo increase product vapor pressure
• BTo contain spilled product and limit environmental release if a tank or piping fails
• CTo serve as the primary pressure boundary of the tank
• DTo replace firefighting access roads

When connecting new field piping to an existing pressurized system, what is the safest general practice before cutting or welding?

• AAssume the line is empty because gauges read zero at a distant panel
• BIsolate, depressurize, drain or purge, and verify zero energy with locks/tags and gas tes…
• COpen the line while it remains at full operating pressure
• DRely only on odor to confirm no hydrocarbons are present

What is the purpose of a field joint coating after a girth weld is completed and accepted?

• ATo replace the need for cathodic protection forever
• BTo restore corrosion protection over the cutback area where mill coating was removed for…
• CTo increase the pipe wall thickness structurally
• DTo mark the weld for GPS survey only

Which statement best describes API 5L pipe used in oil and gas pipeline construction?

• AIt is only a standard for concrete culvert pipe
• BIt is a specification for line pipe used to transport oil, gas, and related fluids
• CIt replaces OSHA excavation standards
• DIt applies only to plastic water service tubing

During lowering-in of coated pipe, what is a primary contractor control to protect the coating?

• ADrag the pipe along rocky trench walls to clean mill scale
• BUse padded belting or non-metallic slings and avoid sharp contact with trench walls and e…
• CRemove all padding so the pipe rests directly on large rocks
• DStrike the coating with hammers to seat the pipe in the ditch

What is the principal reason for using a cone roof or dome roof fixed-roof tank rather than an open-top tank for volatile products?

• AFixed roofs always allow unlimited internal pressure
• BA fixed roof reduces product exposure, weather entry, and vapor release compared with an…
• COpen-top tanks are stronger for high pressure
• DFixed roofs eliminate all need for vents

Which foundation issue is most critical to control under a large aboveground oil storage tank?

• AUniform, adequate bearing support and settlement control to prevent shell and bottom dist…
• BUsing only loose topsoil with no compaction
• CPlacing the tank on untreated organic peat with no engineered pad
• DOmitting any drainage from under the tank bottom

What is a “pig” used for in pipeline operations and commissioning?

• AA small excavation machine for rock ditching only
• BA device propelled through the pipeline to clean, batch, or inspect the interior
• CA type of floating roof seal
• DA sacrificial anode alloy exclusive to tanks

Why must mill scale and loose rust be removed from steel surfaces before applying protective coatings on tanks or pipe?

• AMill scale improves long-term coating adhesion if left intact under all conditions
• BLoose scale and rust prevent proper adhesion and create under-film corrosion sites
• CCoatings only stick to dirty surfaces
• DSurface preparation is optional when cathodic protection is installed

Which statement best describes the role of pressure-vacuum vents on a fixed-roof storage tank?

• AThey permanently seal the tank with no airflow allowed
• BThey relieve excess pressure during filling and vacuum during emptying while limiting con…
• CThey replace the tank foundation
• DThey are used only on buried concrete tanks

In oil field gathering systems, what is a common purpose of a separator or production tank battery near the well site?

• ATo separate gas, oil, and water streams and provide temporary storage before transport
• BTo generate electrical power for the county grid only
• CTo act as the primary drilling bit
• DTo replace all pipeline welding standards

What is the primary hazard of trapped air pockets during hydrostatic testing of a pipeline?

• AAir pockets make the test more conservative and are always desirable
• BCompressed air stores more energy than water and can cause violent rupture behavior if a…
• CAir pockets automatically repair coating holidays
• DAir eliminates the need for test pressure recording

Which practice best protects a buried steel pipeline at a road or railroad crossing?

• AInstall the carrier pipe with no coating and no casing, resting on sharp rock
• BUse approved casing, coating, and clearances per design, with vents and seals as required…
• CLeave the trench open permanently under traffic
• DWeld the pipe solidly to the rail steel for grounding only

What is the main reason API 650 shell courses are often thicker near the bottom than near the top?

• ABottom courses experience higher hydrostatic liquid pressure and must resist greater hoop…
• BTop courses always store more product weight than bottom courses
• CThinner bottom plate improves cathodic protection automatically
• DShell thickness must increase with height for all roof designs

When installing underground pipe near existing utilities, what is the contractor’s first coordination step before excavating?

• ADig immediately with a large toothed bucket to save time
• BNotify the one-call system (Alabama 811) and wait for locate marks as required by law
• CAssume all utilities are deeper than 10 feet
• DUse explosives for every utility corridor

What is the function of a choke or restriction orifice in some oil field flow lines?

• ATo permanently stop all flow with no recovery
• BTo control flow rate and reduce pressure for safe handling downstream
• CTo replace pipeline coating
• DTo act as a sacrificial anode

Which condition most justifies using API 620 instead of API 650 for a field storage tank?

• AThe tank will store product at essentially atmospheric pressure with no design gas-space…
• BThe design requires low internal pressure in the vapor space above atmospheric limits of…
• CThe tank will be fabricated entirely from untreated wood
• DThe owner wants no welding of any kind

What is the primary purpose of a tank water draw-off or boot water connection?

• ATo inject air into the vapor space continuously
• BTo remove free water that settles to the bottom of the oil storage tank
• CTo replace roof drainage on floating roofs only
• DTo heat the foundation with steam automatically

During pipeline bending for horizontal direction changes, what must the contractor protect against?

• AExcessive ovality, wrinkles, and coating damage that reduce pipe strength or create leak…
• BMaking the bend radius infinite so the pipe remains perfectly straight always
• CUsing only heat far above metallurgical limits with no control
• DEliminating all bend data from as-built records

What is the purpose of a floating-roof seal system on an external floating roof tank?

• ATo lock the roof permanently at the top of the shell
• BTo reduce the annular rim vapor gap between the roof and shell, limiting emissions and fi…
• CTo support the full foundation load of the tank
• DTo replace secondary containment dikes

Which statement correctly describes a typical construction sequence for a buried welded steel pipeline?

• AHydrotest first, then trench, then weld, then coat
• BClear/grade ROW, trench, string, weld and NDT, coat field joints, holiday test, lower-in,…
• CBackfill before welding so the pipe cannot move
• DApply field joint coating before welding the girth weld

What is the principal construction concern when installing tank nozzles that penetrate the shell near the bottom?

• ANozzles never require reinforcement or careful weld quality
• BProper reinforcement, weld quality, and orientation so nozzle loads and liquid head do no…
• CInstalling nozzles only after the tank is filled with product
• DUsing wooden plugs as the permanent pressure boundary

Why are insulation and heat tracing sometimes installed on oil field process piping and tanks?

• ATo increase heat loss deliberately in winter
• BTo maintain product temperature, prevent freeze-up, and reduce wax or hydrate problems in…
• CTo replace all pressure relief devices
• DTo eliminate the need for pipe supports

What is the primary purpose of a pipeline right-of-way (ROW) grading and drainage plan before ditching?

• ATo create uncontrolled ponding over the trench line
• BTo provide stable working access, control erosion, and keep the ditch and pipe free of st…
• CTo eliminate all environmental permits
• DTo force all surface water into the open trench permanently

Which test is commonly used to verify a completed API storage tank for leaks before placing it in hydrocarbon service?

• AOnly a visual check of exterior paint gloss
• BHydrostatic fill test (or other approved leak test method specified by the standard and o…
• CSoil resistivity mapping of the dike only
• DUltrasonic testing of the dike soil

What is a major construction risk when welding inside or on a tank that previously held hydrocarbons?

• AThere is never residual flammable vapor after the tank looks empty
• BResidual product and vapor can ignite, so cleaning, gas-freeing, and a hot-work permit sy…
• CHydrocarbon tanks cannot be repaired under any permit system
• DOnly cold water is needed; no atmospheric testing is useful

Which description best fits a “manifold” at an oil field tank battery?

• AA header system of valves and piping that directs flow between wells, separators, tanks,…
• BA single blind flange with no connections
• COnly the tank foundation ringwall
• DA type of floating roof pontoon exclusive to API 620 cryogenic tanks

When is double-jointing of pipe commonly performed in pipeline construction?

• AOnly after the completed line is buried and hydrotested
• BIn a yard or on the ROW to weld two joints into a longer length before stringing or lower…
• COnly on plastic water service lines
• DAs a substitute for all NDT of production welds

What is the primary reason for installing expansion loops or offsets in aboveground oil field piping?

• ATo eliminate all need for pipe supports
• BTo absorb thermal expansion and contraction without overstressing anchors, equipment nozz…
• CTo increase permanent residual stress intentionally
• DTo serve as the only form of corrosion protection

What is the primary purpose of cathodic protection (CP) on a buried steel pipeline?

• ATo heat the product during winter
• BTo make the pipe the cathode of an electrochemical cell so external corrosion is reduced
• CTo increase internal operating pressure capacity
• DTo replace all external coatings completely in every case

Which materials are commonly used as sacrificial anodes for cathodic protection of buried steel structures?

• AGold and platinum only
• BMagnesium, zinc, or aluminum alloys more active than steel
• CStainless steel identical to the pipe grade
• DConcrete without metal

How does an impressed-current cathodic protection system differ from a sacrificial anode system?

• AImpressed current uses an external DC power source (rectifier) and inert or semi-inert an…
• BImpressed current never requires any power source
• CImpressed current only paints the pipe with zinc dust
• DThere is no difference; the terms are identical

What is the purpose of measuring pipe-to-soil potential on a cathodically protected pipeline?

• ATo determine product API gravity only
• BTo assess whether adequate protective potential is being achieved relative to a reference…
• CTo measure welding amperage during girth welding
• DTo replace hydrostatic testing completely

Why is electrical isolation often installed between a cathodically protected pipeline and aboveground facilities or foreign structures?

• ATo increase stray current pickup intentionally in all cases
• BTo prevent CP current from being drained onto foreign metal and to control interference
• CTo eliminate all grounding for electrical safety
• DTo make the pipe act as a lightning rod exclusively

What is a common method to protect the soil side of a steel tank bottom from corrosion?

• ALeave bare steel on wet soil with no protection
• BUse a combination of coatings, sand/asphalt pads or liners, drainage, and cathodic protec…
• CFill the dike with salt water permanently under the tank
• DRely only on painting the roof exterior

What is the purpose of a dielectric coating on buried steel pipe?

• ATo conduct large CP currents through the coating film itself as a conductor
• BTo form a high-resistance barrier that isolates steel from corrosive soil electrolytes
• CTo dissolve quickly so bare steel is always exposed
• DTo increase pipe diameter for flow capacity