DDHub-Semantic-Interoperability

Vocabulary development. Guidelines and definitions

The vocabulary development consists in enumerating the nouns and verbs that can be used to construct a semantic graph. The semantic graph enables detailed contextualization of the drilling real-time signals available during drilling operations.

As seen from a graph perspective:

• Nouns refer to the nature of a node in the graph. Implicitely a noun refers to a “is a” relation between the node and the noun.
• Verbs refer to labels placed on the edges of the graph.

Remark: The templates have been slightly modified: we don’t edit the links anymore. They are now edited automatically. The results ofthe automatic edition can be found under the auto-generated folder.

We use markdown to write the documents. Information about the langage can be found there. Inclusion of figures is dones using the following template:

![Label](relative path to the image)

Definition set files

The vocabulary definitions are split among several files, to facilitate the edition. Each file is called a Definition set file. It is possible to provide an overall description of the topic covered by a single file. The name of the topic is extracted from the file name. The overall structure of such a file is as follows:

- Description:

# NOUNS

# VERBS

Below is an example, taken from the DWISSemantics.md file:

- Description: definitions of the base noun and verb. All verbs and nouns in the DWIS vocabulary are children of those. 

# NOUNS
## DWISNoun <!-- NOUN -->
- Display name: DWIS noun
- Parent class: 
- Attributes:
- Specialization:
- Description: 
- Examples:

# VERBS
## DWISVerb <!-- VERB -->
- Display name: DWIS verb
- Parent verb: 
- Subject class: DWISNoun
- Object class: DWISNoun
- Description: 
- Examples: 

Nouns

A noun is fully characterized by:

• a name
• a display name
• a parent noun
• an attribute list:
  • attribute name, type and description
• some specialization values:
  • attribute name and value
• a description
• some examples

Name

The identification name of the noun. It should ideally follow some notational convention.

Display name

A variant of the name used for pretty printing of the noun. It can have a more human friendly syntax.

Parent relation

There can be relations between nouns. We only consider sub-typing relations. Each noun is associated to a (unique) parent. Circular parenting is not permitted. There is a common ancestor to all nouns: DWISNode. One can therefore derive a tree structure from the nouns. The parent relation should be consistent with the is a relation. For example, if the DeadlineHookload noun has parent the Hookload noun, then consistency is in place. When asserting that a signal s is a DeadlineHookload, one implicitely asserts that s is a Hookload, which is true. A contrario, stating the the noun TopDriveShaft has parent noun TopDrive is erroneous: if an element e is a TopDriveShaft, then one implicitely asserts that e is also a TopDrive, which is false. In this example, using the parent relation between TopDriveShaft and TopDrive is not correct. One should instead use a is made of relation, or something similar.

Attributes

Nouns can define a set of attributes. An attribute is characterized by:

• a name
• a data type. We only consider simple data types (see e.g. the ones used in RDF)
• attributes are inherited from the parent type.
• the value of attributes can be specialized.

Specialization values

Description

Examples

Template

Below is an empty template that can be used to define a new noun.

## NounName <!-- NOUN -->
- Display name: MechanicalElementState
- Parent class: Noun name
- Attributes:
  - AttributeName
    - Type: bool
    - Description: 
- Specialization:
  - AttributeName = default value
- Description: 
- Examples:

Below is an example:

## HighPassFilter <!-- NOUN -->
- Display name: HighPassFilter
- Parent class: Filter
- Attributes:
  - CutOffFrequency
    - Type: double
    - Description: 
- Specialization:
- Description: 
- Examples:

## Verbs Verbs are used to connect nodes in the graph. Verbs are identified by their name, and do not support parametrization. A verb is characterized by:

• a name
• a display name
• a parent verb
• a subject type (domain)
• an object class (range)
• a description
• some examples.

Template

## VerbName <!-- VERB -->
- Display name: verb display name
- Parent verb: verb name
- Subject class: Noun name
- Object class: Noun name
- Description: 
- Examples: 

Below is an example:

## IsResampledBy <!-- VERB -->
- Display name: IsResampledBy
- Parent verb: IsTransformationOutput
- Subject class: DrillingDataPoint
- Object class: Resampling
- Description: 
- Examples: 

Examples

It ispossible to write down example, to illustrate the intended usage of the introduced nouns and verbs. Both verbs and nouns templates have an example field, and the syntax will be similar. An example is characterized by:

• the example name
• a list of instance declarations. An instance declaration is the combination of the instance name and of its declaration noun
• a list of sentences. A sentence is a triplet of the form:
  • subject: an instance
  • verb: a verb…
  • object: an instance. The template for examples is as follows:

- Examples:
  - Example name
    - NounName1:instanceName1 //declaration of the first instance
    - NounName2:instanceName2 //declaration of the second instance    
    - NounName3:instanceName3 //declaration of the third instance
    - ...
    - instanceName1 verbs1 instanceName1 //the first sentence
    - instanceName2 verb2 instanceName2 //the second sentence

For example:

- Examples:
  - Downhole ECD example
    - DrillingDataPoint:downholeECD 
    - PressureToEquivalentDensityTransformation:trans 
    - DrillingDataPoint:downholePressure 
    - downholePressure isTransformationInput trans 
    - downholeECD isTransformationOutput trans 
  - Downhole ECD example with TVD
    - DrillingDataPoint:downholeECD 
    - DrillingDataPoint:TVD
    - PressureToEquivalentDensityTransformation:trans 
    - DrillingDataPoint:downholePressure 
    - downholePressure isTransformationInput trans 
    - TVD isTransformationInput trans 
    - downholeECD isTransformationOutput trans 

Categories

• DataFlow: this category refers to the data processing. It should probably be renamed accordingly. It should define and organize the different types of processing encountered during drilling operations. A Thursday session was devoted to those items. Note that in the current version, control flow is also included: a controller is seen as a special type of processing unit, that generates commands based on measurements and set-points. This can of course be modified if deemed necessary. Note also that transmission is included there as well. A telemetry system is seen as a processing unit that only duplicates a signal, and a delay is associated to the duplication process. While this is a useful way of looking at telemetry, it is probably not intuitive enough.
• DataTransmission: this category contains all nouns and verbs used to describe the rig’s telemetry, for each signal. Downhole telemetry has focus.
• DataValidity: this category contains all the nouns and verbs used to described the validity of signals. Some signals are for example only valid while off-slips, downhole signals transmitted via mud-pulse telemetry require circulation.
• DrillingDataSemantics: this is the part associated to the signal’s description themselves. Dimensionality, data type are the main items to be described.
• DrillingEquipment: in this category fall all the standard equipment encountered on a drilling rig. Note that the goal of the vocabulary is not to provide a detailed description of the rig. Therefore we only consider nouns that can help providing a signal context.
• Hydraulics: this part refers to the hydraulic circuit, and should only contain the “abstract” or conceptual part of the vocabulary. Additional nouns coming from the drilling equipment category will be used when constructing the semantic graphs.
• Mechanics: this part refers to the mechanical circuit, and should only contain the “abstract” or conceptual part of the vocabulary. Additional nouns coming from the drilling equipment category will be used when constructing the semantic graphs.
• PhysicalLocation: this category contains the vocabulary necessary to specify the location of various items on a rig. Coordinate systems are the main element here.
• Quantities: quantities and units.
• TimeManagement: this category referes mostly to the description of the various clocks that can be encoutered on a rig, and their synchronization status with respect to each other.
• Uncertainty: this category contains the nouns and verbs required to describe the various types of uncertainty attached to drilling signals. Uncertainties can be related to sensor characteristics, calculations, model calibration, data assimilation.

Open Questions

Questions are discussed here

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