Operating Margin

Operating Margin

Definition(s)

Drilling margin or drilling window or operating margin

The difference between the maximum pore pressure and the minimum effective fracture pressure. It is used while drilling and can be determined for any point within an open-hole interval. NOTE Drilling margin is usually expressed in terms of equivalent mud weight. Source: API RP 96, Deepwater Well Design and Construction, First Edition, March 2013. Global Standards
Drilling Window

Drilling Window

Definition(s)

Drilling margin or drilling window or operating margin

The difference between the maximum pore pressure and the minimum effective fracture pressure. It is used while drilling and can be determined for any point within an open-hole interval. NOTE Drilling margin is usually expressed in terms of equivalent mud weight. Source: API RP 96, Deepwater Well Design and Construction, First Edition, March 2013. Global Standards
Drilling Margin

Drilling Margin

Definition(s)

Drilling margin or drilling window or operating margin

The difference between the maximum pore pressure and the minimum effective fracture pressure. It is used while drilling and can be determined for any point within an open-hole interval. NOTE Drilling margin is usually expressed in terms of equivalent mud weight. Source: API RP 96, Deepwater Well Design and Construction, First Edition, March 2013. Global Standards
Design Factor

Design Factor

Definition(s)

Design Factor

Factor (utilization factor equal to one or less) used to set load limit. Source: API Standard 2RD, Dynamic Risers for Floating Production Systems, Second Edition, September 2013. Global Standards

Design Factor

Minimum acceptable ratio of the capacity of a component to the load to which it can be subjected. Source: Source: API RP 96, Deepwater Well Design and Construction, First Edition, March 2013. Global Standards  

Design Factor

Factor (usage factor) used in working stress design. Source: API RP 17G, Recommended Practice for Completion/Workover Risers, Second Edition, July 2006 (Reaffirmed April 2011). Global Standards  

Design Factor

Ratio between the rated strength of the material over the estimated load. Source: NORSOK D-010, Well integrity in drilling and well operations, Rev. 3, August 2004. Global Standards
Deepwater Well

Deepwater Well

Definition(s)

Deepwater well

Offshore well where subsea BOPs are used. Source: API RP 96, Deepwater Well Design and Construction, First Edition, March 2013. Global Standards
Deadman System

Deadman System

Definition(s)

Deadman system

A safety system designed to automatically shut in the wellbore in the event of a simultaneous absence of hydraulic supply and control of both subsea control pods. Source: API RP 96, Deepwater Well Design and Construction, First Edition, March 2013. Global Standards
Confirmed Barrier

Confirmed Barrier

Definition(s)

Confirmed barrier

A barrier whose performance has been verified by satisfying placement acceptance criteria through evaluating data collected during installation. NOTE A confirmed barrier has a lower level of assurance than a tested barrier. EXAMPLE A barrier that is intended to resist pressure from below during its service is tested successfully after installation with pressure from above. The barrier in this scenario is considered to be a confirmed barrier but does not meet the definition of a tested barrier because it was not tested in the direction of flow in service. Source: API RP 96, Deepwater Well Design and Construction, First Edition, March 2013. Global Standards
Cement Barrier

Cement Barrier

Definition(s)

Cement barrier

A cement column designed and placed to prevent formation fluid or gas flow between geologic formations, within annular spaces, or in the wellbore (a subset of physical barriers). Source: API RP 96, Deepwater Well Design and Construction, First Edition, March 2013. Global Standards
Containment Stack

Containment Stack

Definition(s)

Capping stack or containment stack

A device that controls, diverts, and shuts in a well flow stream during a well containment operation. NOTE This equipment is deployed only as required and is not a part of standard rig equipment. Source: API RP 96, Deepwater Well Design and Construction, First Edition, March 2013. Global Standards
Capping Stack

Capping Stack

Definition(s)

Capping stack or containment stack

A device that controls, diverts, and shuts in a well flow stream during a well containment operation. NOTE This equipment is deployed only as required and is not a part of standard rig equipment. Source: API RP 96, Deepwater Well Design and Construction, First Edition, March 2013. Global Standards
Basis of Design

Basis of Design

Definition(s)

Basis of design

All information and assumptions utilized to design the well. Source: API RP 96, Deepwater Well Design and Construction, First Edition, March 2013. Global Standards
Barrier System

Barrier System

Definition(s)

Barrier system

A combination of barriers acting together to prevent unintended fluid and/or gas flow. NOTE The barrier system includes both physical and operational barriers. Source: API RP 96, Deepwater Well Design and Construction, First Edition, March 2013. Global Standards
Barrier Plan

Barrier Plan

Definition(s)

Barrier plan

The operator’s specific operating procedure for barrier placement, verification, and removal. Source: API RP 96, Deepwater Well Design and Construction, First Edition, March 2013. Global Standards
Backup Gradient

Backup Gradient

Definition(s)

Backup gradient

Hydrostatic gradient of fluid assumed to be on the other side of the tubular string from the design load case being considered. NOTE Typically subtracted from the design pressure load profile in order to calculate a “net” pressure. Source: API RP 96, Deepwater Well Design and Construction, First Edition, March 2013. Global Standards
Autoshear System

Autoshear System

Definition(s)

Autoshear system

A safety system that is designed to automatically shut-in the wellbore in the event of a disconnect of the LMRP. NOTE When the autoshear is engaged, disconnecting the LMRP closes the shear rams. Source: API RP 96, Deepwater Well Design and Construction, First Edition, March 2013. Global Standards
Can

Can

Definition(s)

Can

The term “can” is used to express possibility or capability. Source: API RP 96, Deepwater Well Design and Construction, First Edition, March 2013. Global Standards  

Can

“Can”, means an alternative, equal way of fulfilling the regulatory requirements, e.g. where the guidelines recommend using maritime standards as an alternative to following a NORSOK standard. Source: Guidelines Regarding the Framework Regulations, Norway, updated December 2012. Regulatory Guidance  

Can

Verbal form used for statements of possibility and capability, whether material, physical or casual. Source: NORSOK D-010, Well integrity in drilling and well operations, Rev. 3, August 2004. Global Standards Source: NORSOK D-002, Well intervention equipment, Rev. 2, June 2013. Global Standards  

Can

Can requirements are conditional and indicates a possibility open to the user of the standard. Source: NORSOK D-007, Well Testing Systems, Rev. 1, January 1996. Global Standards  

Can

verbal form used for statements of possibility and capability whether material, physical or casual Source: Rules for Classification and Construction, IV Industrial Services, 6 Offshore Technology, 9 Guideline for Personnel Transfers by Means of Lifting Appliances, Edition 2011, Germanischer Lloyd SE, Global Standards
Well Simulation Test

Well Simulation Test

Definition(s)

Well Simulation Test

Test whose parameters are designed and modified as required to simulate the conditions found in a wellbore. Source: API RP 10B-2, Recommended Practice for Testing Well Cements, First Edition, July 2005 (Reaffirmed: July 2010). Global Standards
Weigh Batch Mixer

Weigh Batch Mixer

Definition(s)

Weigh Batch Mixer (or Scale Tank)

Device or system for the weighing and blending of cement with dry additives. Source: API RP 10B-2, Recommended Practice for Testing Well Cements, First Edition, July 2005 (Reaffirmed: July 2010). Global Standards
Thickening Time

Thickening Time

Definition(s)

Thickening Time

Time required for a cement slurry to develop a selected Bearden consistency value. NOTE The results of a thickening-time test provide an indication of the length of time a cement slurry can remain pumpable under the test conditions. Source: API RP 10B-2, Recommended Practice for Testing Well Cements, First Edition, July 2005 (Reaffirmed: July 2010). Global Standards  

Thickening Time

Time after which the consistency of a cement slurry has become so high that the slurry is considered unpumpable. NOTE The results of a thickening-time test provide an indication of the length of time a cement slurry remains pumpable under the test conditions. Source: API SPEC 10A, Specification for Cements and Materials for Well Cementing, Twenty-fourth Edition, December 2010. Global Standards
Strength Retrogression

Strength Retrogression

Definition(s)

Strength Retrogression

Reduction in compressive strength and increase in permeability of a cement caused by exposure to temperatures exceeding 110 °C (230 °F). Source: API RP 10B-2, Recommended Practice for Testing Well Cements, First Edition, July 2005 (Reaffirmed: July 2010). Global Standards
Stirred Fluid-Loss Cell

Stirred Fluid-Loss Cell

Definition(s)

Stirred Fluid-Loss Cell

Cell specially designed to allow for conditioning of the cement slurry within the same cell used to perform a static fluid loss test. Source: API RP 10B-2, Recommended Practice for Testing Well Cements, First Edition, July 2005 (Reaffirmed: July 2010). Global Standards
Static Stability Test

Static Stability Test

Definition(s)

Static Stability Test

Test to determine the degree of sedimentation and free fluid development in a cement slurry. Source: API RP 10B-2, Recommended Practice for Testing Well Cements, First Edition, July 2005 (Reaffirmed: July 2010). Global Standards
Static Fluid Loss Test

Static Fluid Loss Test

Definition(s)

Static Fluid Loss Test

Test to determine fluid lost from a cement slurry when placed against a 325 mesh screen at 6 900 kPa (1 000 psi) differential pressure. Source: API RP 10B-2, Recommended Practice for Testing Well Cements, First Edition, July 2005 (Reaffirmed: July 2010). Global Standards
Starting Pressure

Starting Pressure

Definition(s)

Starting Pressure (pS)

Initial pressure applied to the test sample at the beginning of the thickening-time test. NOTE pS is also used to determine the pressure-up rate. Source: API RP 10B-2, Recommended Practice for Testing Well Cements, First Edition, July 2005 (Reaffirmed: July 2010). Global Standards
Sonic Strength

Sonic Strength

Definition(s)

Sonic Strength

Extent of strength development of a cement sample calculated by measuring the velocity of sound through it. NOTE The calculation is based on specific mathematical correlations and not on direct measurements of strength. Source: API RP 10B-2, Recommended Practice for Testing Well Cements, First Edition, July 2005 (Reaffirmed: July 2010). Global Standards
Slurry Container

Slurry Container

Definition(s)

Slurry Container

Container in a pressurized consistometer used to hold the slurry for conditioning purposes or for thickeningtime test. Source: API RP 10B-2, Recommended Practice for Testing Well Cements, First Edition, July 2005 (Reaffirmed: July 2010). Global Standards
Sedimentation

Sedimentation

Definition(s)

Sedimentation

Separation and settling of solids in a cement slurry. Source: API RP 10B-2, Recommended Practice for Testing Well Cements, First Edition, July 2005 (Reaffirmed: July 2010). Global Standards
Relative Density

Relative Density

Definition(s)

Relative Density (or Specific Gravity)

Ratio of the mass of a substance to the mass of an equal volume of a standard substance at a reference temperature. NOTE The standard substance is usually water; the reference temperature is usually 4 °C. Source: API RP 10B-2, Recommended Practice for Testing Well Cements, First Edition, July 2005 (Reaffirmed: July 2010). Global Standards
Subsea Wells

Subsea Wells

Definition(s)

Subsea Wells

Wells drilled and completed with a subsea wellhead located near the seafloor. Source: API STD 65 – Part 2, Isolating Potential Flow Zones During Well Construction, Upstream Segment, Second Edition, December 2010. Global Standards  

Subsea Well

Wells completed with a subsea wellhead and a subsea tree. Source: ISO 16530-1:2017, Petroleum and natural gas industries — Well integrity – Part 1: Life cycle governance, First Edition, March 2017. Global Standards Source: API RP 90, Annular Casing Pressure Management for Offshore Wells, Upstream Segment. First Edition, August 2006. Global Standards
Pressure-Up Rate (Rpu)

Pressure-Up Rate (Rpu)

Definition(s)

Pressure-Up Rate (Rpu)

Rate at which pressure is increased from the starting pressure to the bottom-hole pressure during a thickeningtime test. Source: API RP 10B-2, Recommended Practice for Testing Well Cements, First Edition, July 2005 (Reaffirmed: July 2010). Global Standards