Glossary
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Spudcan
Definition(s)
Spudcan
A large inverted cone that is roughly circular in-plan with a shallow conical underside and a sharp protruding spigot. It is mounted at the base of a jackup’s leg, and is primarily considered to provide sliding and bearing resistance to the jackup rig when deployed into the sea bed.
Source: ABS Guidance Notes on Geotechnical Performance of Spudcan Foundations, January 2017. Global StandardsSpudcan
Structure at the base of a leg supported by the soil. Source: ISO 19905-1:202, Petroleum and natural gas industries – Site-specific assessment of mobile offshore units – Part 1: Jack-ups. Global StandardsSpectral Peak Period
Definition(s)
Spectral Peak Period
period of the maximum (peak) energy density in the spectrum NOTE In practice there is often more than one peak in a spectrum. Source: API RP 2MET, Derivation of Metocean Design and Operating Conditions, First Edition, November 2014. Global StandardsSpectral Peak Period
Period of the maximum (peak) energy density in the spectrum. NOTE 1 In practice, there is often more than one peak in a spectrum. NOTE 2 There are two types of spectral peak period used within this part of ISO 19905: intrinsic and apparent. The distinction is discussed in A.7.3.3.5, which is, in turn, based on ISO 19901-1:2005, 8.3 and A.8.3. NOTE 3 Adapted from ISO 19901-1:2005, definition 3.32. Source: ISO 19905-1:202, Petroleum and natural gas industries – Site-specific assessment of mobile offshore units – Part 1: Jack-ups. Global StandardsSpectrum
Definition(s)
Spectrum
Measure of the variance associated with a time-varying variable per unit frequency band and per unit directional sector. NOTE 1 Spectrum is a shorthand expression for the full and formal name of spectral density function or energy density function. NOTE 2 The spectral density function is the variance (the mean square) of the time-varying variable concerned in each frequency band and directional sector. Therefore, the spectrum is, in general, written with two arguments: one for the frequency variable and one for a direction variable. NOTE 3 Within ISO 19901-1, the concept of a spectrum applies to waves, wind turbulence and action effects (responses) that are caused by waves or wind turbulence. For waves, the spectrum is a measure of the energy traversing a given space. [ISO 19901-1:2005, definition 3.33]. Source: API RP 2MET, Derivation of Metocean Design and Operating Conditions, First Edition, November 2014. Global Standards Source: ISO 19905-1:202, Petroleum and natural gas industries – Site-specific assessment of mobile offshore units – Part 1: Jack-ups. Global StandardsEnergy Density Function
Definition(s)
Energy Density Function
Measure of the variance associated with a time-varying variable per unit frequency band and per unit directional sector. NOTE 1 Spectrum is a shorthand expression for the full and formal name of spectral density function or energy density function. NOTE 2 The spectral density function is the variance (the mean square) of the time-varying variable concerned in each frequency band and directional sector. Therefore, the spectrum is, in general, written with two arguments: one for the frequency variable and one for a direction variable. NOTE 3 Within ISO 19901-1, the concept of a spectrum applies to waves, wind turbulence and action effects (responses) that are caused by waves or wind turbulence. For waves, the spectrum is a measure of the energy traversing a given space. [ISO 19901-1:2005, definition 3.33]. Source: API RP 2MET, Derivation of Metocean Design and Operating Conditions, First Edition, November 2014. Global Standards Source: ISO 19905-1:202, Petroleum and natural gas industries – Site-specific assessment of mobile offshore units – Part 1: Jack-ups. Global StandardsSpectral Density Function
Definition(s)
Spectral Density Function
Measure of the variance associated with a time-varying variable per unit frequency band and per unit directional sector. NOTE 1 Spectrum is a shorthand expression for the full and formal name of spectral density function or energy density function. NOTE 2 The spectral density function is the variance (the mean square) of the time-varying variable concerned in each frequency band and directional sector. Therefore, the spectrum is, in general, written with two arguments: one for the frequency variable and one for a direction variable. NOTE 3 Within ISO 19901-1, the concept of a spectrum applies to waves, wind turbulence and action effects (responses) that are caused by waves or wind turbulence. For waves, the spectrum is a measure of the energy traversing a given space.[ISO 19901-1:2005, definition 3.33]. Source: API RP 2MET, Derivation of Metocean Design and Operating Conditions, First Edition, November 2014. Global Standards Source: ISO 19905-1:202, Petroleum and natural gas industries – Site-specific assessment of mobile offshore units – Part 1: Jack-ups. Global StandardsSpecial Survey
Definition(s)
Special Survey
Extensive and complete survey carried out at each nominal five year interval, which closes a cycle of annual classification and mandatory surveys. NOTE Also referred to as “renewal survey” by some IACS members. Source: ISO 19905-1:202, Petroleum and natural gas industries – Site-specific assessment of mobile offshore units – Part 1: Jack-ups. Global StandardsSliding
Definition(s)
Sliding
Horizontal movement of a spudcan. Source: ISO 19905-1:202, Petroleum and natural gas industries – Site-specific assessment of mobile offshore units – Part 1: Jack-ups. Global StandardsSlant-Leg Unit
Definition(s)
Slant-Leg Unit
Jack-up with legs that can be inclined at a significant angle to the vertical. NOTE The inclination angle is typically about 5°. The benefit is that the jack-up behaves more like a braced frame and less like a portal frame, with accompanying reductions in leg axial forces and moments. Source: ISO 19905-1:202, Petroleum and natural gas industries – Site-specific assessment of mobile offshore units – Part 1: Jack-ups. Global StandardsSkirted Spudcan
Definition(s)
Skirted Spudcan
Spudcan with a peripheral skirt. Source: ISO 19905-1:202, Petroleum and natural gas industries – Site-specific assessment of mobile offshore units – Part 1: Jack-ups. Global StandardsSignificant Wave Height
Definition(s)
Significant Wave Height
statistical measure of the height of waves in a sea state NOTE The significant wave height was originally defined as the mean height of the highest one-third of the zero upcrossing waves in a sea state. In most offshore data acquisition systems the significant wave height is currently taken as 4 m0 (where m0 is the zeroth spectral moment, see 3.31) or 4σ, where σ is the standard deviation of the time series of water surface elevation over the duration of the measurement, typically a period of approximately 30 min. Source: API RP 2MET, Derivation of Metocean Design and Operating Conditions, First Edition, November 2014. Global StandardsSignificant Wave Height
Statistical measure of the height of waves in a sea state. NOTE The significant wave height was originally defined as the mean height of the highest one-third of the zero upcrossing waves in a sea state. In most offshore data acquisition systems, the significant wave height is currently taken as (where m0 is the zeroth spectral moment, see ISO 19901-1:2005, definition 3.31) or 4σ, where σ is the standard deviation of the time series of water surface elevation over the duration of the measurement, typically a period of approximately 30 min. [ISO 19901-1:2005, definition 3.30]. Source: ISO 19905-1:202, Petroleum and natural gas industries – Site-specific assessment of mobile offshore units – Part 1: Jack-ups. Global StandardsSignificant Wave Height
average height of the highest third of prevailing waves, typically measured over a period of 3 hours . Source: ISO 19905-1:202, Petroleum and natural gas industries – Site-specific assessment of mobile offshore units – Part 1: Jack-ups. Global StandardsShallow Gas
Definition(s)
Shallow Gas
Gas pockets or entrapped gas below impermeable layers at shallow depth. Source: ISO 19905-1:202, Petroleum and natural gas industries – Site-specific assessment of mobile offshore units – Part 1: Jack-ups. Global StandardsSea State
Definition(s)
Sea State
Condition of the sea during a period in which its statistics remain approximately constant. NOTE In a statistical sense the sea state does not change markedly within the period. The period during which this condition exists is usually assumed to be three hours, although it depends on the particular weather situation at any given time. [ISO 19901-1:2005, definition 3.26]. Source: ISO 19905-1:202, Petroleum and natural gas industries – Site-specific assessment of mobile offshore units – Part 1: Jack-ups. Global Standards Source: API RP 2MET, Derivation of Metocean Design and Operating Conditions, First Edition, November 2014. Global StandardsScatter Diagram
Definition(s)
Scatter Diagram
Joint probability of two or more (metocean) parameters. NOTE 1 A scatter diagram is especially used with wave parameters in the metocean context, see ISO 19901-1:2005, A.5.8. The wave scatter diagram is commonly understood to be the probability of the joint occurrence of the significant wave height (Hs) and a representative period (Tz,i or Tp,i). NOTE 2 Adapted from ISO 19901-1:2005, definition 3.24. Source: API RP 2MET, Derivation of Metocean Design and Operating Conditions, First Edition, November 2014. Global Standards Source: ISO 19905-1:202, Petroleum and natural gas industries – Site-specific assessment of mobile offshore units – Part 1: Jack-ups. Global StandardsRepresentative Value
Definition(s)
Representative Value
Value assigned to a basic variable for verification of a limit state. [ISO 19900:2002, definition 2.26]. Source: ISO 19905-1:202, Petroleum and natural gas industries – Site-specific assessment of mobile offshore units – Part 1: Jack-ups. Global Standards Source: ISO 19900:2013, Petroleum and natural gas industries – General requirements for offshore structures. Global StandardsPoint of Compliance
Definition(s)
Point of Compliance
POINT OF COMPLIANCE means one or more points or locations at which compliance with applicable groundwater standards established under Water Quality Control Commission Basic Standards for Groundwater, Section 3.11.4, must be achieved. Source: Oil and Gas Conservation Commission, Practice and Procedure, Code of Colorado Regulations, 2 CCR 404-1, February 2013. RegulationsPlugging and Abandonment
Definition(s)
Plugging and Abandonment
PLUGGING AND ABANDONMENT shall mean the cementing of a well, the removal of its associated production facilities, the removal or abandonment in-place of its flowline, and the remediation and reclamation of the wellsite. Source: Oil and Gas Conservation Commission, Practice and Procedure, Code of Colorado Regulations, 2 CCR 404-1, February 2013. RegulationsOrphaned Site
Definition(s)
Orphaned Site
ORPHANED SITE shall mean a site, where a significant adverse environmental impact may be or has been caused by oil and gas operations for which no responsible party can be found, or where such responsible party is unwilling or unable to mitigate such impact. Source: Oil and Gas Conservation Commission, Practice and Procedure, Code of Colorado Regulations, 2 CCR 404-1, February 2013. RegulationsOrphan Well
Definition(s)
Orphan Well
ORPHAN WELL shall mean a well for which no owner or operator can be found, or where such owner or operator is unwilling or unable to plug and abandon such well. Source: Oil and Gas Conservation Commission, Practice and Procedure, Code of Colorado Regulations, 2 CCR 404-1, February 2013. RegulationsOrdinary High-water Line
Definition(s)
Ordinary High-water Line
ORDINARY HIGH-WATER LINE shall mean the line that water impresses on the land by covering it for sufficient periods to cause physical characteristics that distinguish the area below the line from the area above it. Characteristics of the area below the line include, when appropriate, but are not limited to, deprivation of the soil of substantially all terrestrial vegetation and destruction of its agricultural vegetative value. A flood plain adjacent to surface waters is not considered to lie within the surface waters' ordinary high-water line. Source: Oil and Gas Conservation Commission, Practice and Procedure, Code of Colorado Regulations, 2 CCR 404-1, February 2013. RegulationsRPD
Definition(s)
RPD
The difference in elevations between the chords of any one leg.
Source: ABS Guidance Notes on Geotechnical Performance of Spudcan Foundations, January 2017. Global StandardsRPD
Rack Phase Difference. Source: ABS Guidance Notes on Geotechnical Performance of Spudcan Foundations, January 2017. Global Standards Source: ISO 19905-1:202, Petroleum and natural gas industries – Site-specific assessment of mobile offshore units – Part 1: Jack-ups. Global StandardsRPD
Relative difference in the position of adjacent leg chords within a leg measured parallel to the longitudinal axis of the chords. NOTE This is the out-of-plane distortion of the plan-frame. Source: ISO 19905-1:202, Petroleum and natural gas industries – Site-specific assessment of mobile offshore units – Part 1: Jack-ups. Global StandardsRack Phase Difference
Definition(s)
Rack Phase Difference
The difference in elevations between the chords of any one leg.
Source: ABS Guidance Notes on Geotechnical Performance of Spudcan Foundations, January 2017. Global Standards