WITSML

This document contains the following sections:

· Overview

· Data object schema design

· Naming convention in schemas

· WITSML Schemas, XML documents, and Stylesheets

o Version 1.1.0 Changes

o Version 1.2.0 Changes

Overview:

The Wellsite Information Transfer Standard Markup Language (WITSML) is a standard for sending well site information in an XML document format between business partners. XML schemas are used to define the content of an XML document. The WITSML standard consists of data object and component schemas. A data object schema is the smallest set of related data that can be transmitted within an XML document (e.g.; well, wellbore, rig, etc.). Data object schemas contain attributes, elements, and imported component schemas.

Component schemas are XML schemas, but these schemas do not represent complete data objects. A component schema may be imported by more than one data object schema. All component schemas are prefixed with (cs_). Four component schemas are included in all data object schemas:

cs_commonData.xsd – defines common data elements across all data objects. For example, user ID, transaction timestamp, the data object state (itemState), and comments about the data object.
cs_customData.xsd – defines a schema that can be used to extend the WITSML standard. That is, this schema can be modified to include additional data elements not included in the WITSML standard.
cs_catalog.xsd – defines the data types referenced by elements and attributes in WITSML data object and component schemas that are restricted by either size or content. For elements restricted by content, the valid (enumerated) values are defined in this schema.
cs_dataType.xsd – defines all non-restricted data types referenced by elements and attributes in WITSML data object and component schemas.

Data object schema design:

Since all XML documents can only have one root level element and there are instances where it is necessary to send multiple occurrences of a data object in a single XML document (e.g.; multiple wellbores in a well), a pluralized version of the data object name was established as the schema root element. That is, the object name followed by an “S” (e.g.; wells, wellbores, etc.). In some cases, this leads to incorrect pluralization (e.g. trajectorys), but is required to order to meet the requirements of the WITSML API’s which generate tag names based on the data object name.

The unique identifiers (uid) for data objects are always defined as attributes at the singular data object name level (e.g.; uidWell, uidWellbore, etc.). That is, never at the pluralized data object name level. This was done for two reasons;

Simpler navigation of the Document Object Model (DOM) for the schema when creating an XML document.
It will permit the schemas to be used as result set schemas when querying the WITSML server. That is, it will permit information from multiple wells to be returned in a single XML document.

Naming convention in schemas:

The “type” for an element can be either a W3C standard type or a WITSML defined type. The W3C standard types are prefixed with “xsd:” and the WITSML types are prefixed with “witsml:”. A WITSML type can be one of three types; a definition only with possibly a restricted size specified, a definition with enumerated values that are permitted, and a reference to another data object schema or component schema. In order, to help identify which type is being referenced, the following naming convention is used.

Type definition only - starts with lowercase, each new words begin with uppercase.

<xsd:element name="mdKickoff" type="witsml:standardDepthIndex" minOccurs="0"/>

Type definition with enumerated values – starts with uppercase and each new words begin with uppercase.

<xsd:element name="shape" type="witsml:WellboreShape" minOccurs="0"/>

Reference to another data object schema or component schema can be identified by the an “obj_” or “cs_” prefix.

<xsd:element name="trajectoryStation" type="witsml:obj_trajectoryStation" minOccurs="0"

maxOccurs="unbounded"/>

<xsd:element name="pumps" type="witsml:cs_pumps" minOccurs="0" maxOccurs="unbounded"/>

Multi-purpose schemas:

Some schemas are used as both a data object schema and as a component schema. That is, there is a need to transmit the data object independently of other well related data and a need at times to send information as part of another data object. For example, trajectory stations can be sent as an XML document or trajectory stations can be included in a trajectory XML document. Whenever a data object schema is referencing another data object schema, the reference is made to the singular complex type name. For example, <xsd:element name="trajectorystation" type="witsml:obj_trajectoryStation" …. maxOccurs=”unbounded”/>. The example below gives a more complete picture of how this is accomplished.

( This following is a snippet from the trajectory schema definition)

<xsd:element name="trajectorys" type="witsml:obj_trajectorys"/>

<xsd:complexType name="obj_trajectorys">

<xsd:sequence>

<xsd:element name="trajectory" type="witsml:obj_trajectory" maxOccurs="unbounded"/>

</xsd:sequence>

<xsd:attribute name="version" type="xsd:string" use="fixed" value="1.0"/>

</xsd:complexType>

<xsd:complexType name="obj_trajectory">

<xsd:sequence>

<xsd:element name="uidTrajParent" type="witsml:str64" minOccurs="0"/>

<xsd:element name="dTimTrajStart" type="xsd:dateTime" minOccurs="0"/>

(other trajectory elements)

<xsd:element name="station" type="witsml:obj_trajectoryStation" …. maxOccurs=”unbounded”/>

<xsd:element name="commonData" type="witsml:commonData" minOccurs="0"/>

<xsd:element name="customData" type="witsml:customData" minOccurs="0"/>

</xsd:sequence>

<xsd:attribute name="uidWell" type="witsml:str64" use="required"/>

<xsd:attribute name="uidWellbore" type="witsml:str64" use="required"/>

<xsd:attribute name="uidTrajName" type="witsml:str64" use="required"/>

</xsd:complexType>

The “obj_trajectionStation” referenced above is the name of a complex type defined in the obj_trajectoryStation schema.

WITSML Schemas, XML documents, and Stylesheets:

The WITSML standard includes the following data object and component schemas.

BHA Run data object Links to Documents

Schemas	XSD Schema	XML Docu.	XML via Stylesheet	Stylesheet Source
obj_bhaRun.xsd	XSD	XML	XML/XSL	XSL
cs_drillingParams.xsd	XSD
cs_commonData.xsd	XSD
cs_customData.xsd	XSD

Capability of Client Schema Links to Documents

Schemas

XSD

Schema

XML

Docu.

XML via

Stylesheet

Source

obj_capClient

XSD

XML

Capability of Publisher Schema Links to Documents

Schemas

XSD

Schema

XML

Docu.

XML via

Stylesheet

Source

obj_capPublisher

XSD

XML

Capability of Server Schema Links to Documents

Schemas

XSD

Schema

XML

Docu.

XML via

Stylesheet

Source

obj_capServer

XSD

XML

Capability of Client Schema Links to Documents

Schemas

XSD

Schema

XML

Docu.

XML via

Stylesheet

Source

obj_capSubscriber

XSD

XML

Cement Job data object Links to Documents

Schemas	XSD Schema	XML Docu.	XML via Stylesheet	Stylesheet Source
obj_cementJob.xsd	XSD	XML	XML/XSL	XSL
cs_cementStage.xsd	XSD
cs_cementingFluid.xsd	XSD
cs_cementAdditive.xsd	XSD
cs_cementPumpSchedule.xsd	XSD
cs_commonData.xsd	XSD
cs_customData.xsd	XSD

Conventional Core data object Links to Documents

Schemas	XSD Schema	XML Docu.	XML via Stylesheet	Stylesheet Source
obj_convCore.xsd	XSD	XML	XML/XSL	XSL
cs_geologyInterval.xsd	XSD
cs_lithology.xsd	XSD
cs_show.xsd	XSD
cs_chromatograph.xsd	XSD
cs_mudGas.xsd	XSD
cs_commonData.xsd	XSD
cs_customData.xsd	XSD

Fluids Report data object Links to Documents

Schemas	XSD Schema	XML Docu.	XML via Stylesheet	Stylesheet Source
obj_fluidsReport.xsd	XSD	XML	XML/XSL	XSL
cs_fluids.xsd	XSD
cs_rheometer.xsd	XSD
cs_commonData.xsd	XSD
cs_customData.xsd	XSD

Formation Marker data object Links to Documents

Schemas	XSD Schema	XML Docu.	XML via Stylesheet	Stylesheet Source
obj_formationMarker.xsd	XSD	XML	XML/XSL	XSL
cs_commonData.xsd	XSD
cs_customData.xsd	XSD

Log data object Links to Documents

Schemas	XSD Schema	XML Docu.	XML via Stylesheet	Stylesheet Source
obj_log.xsd	XSD	XML	XML/XSL	XSL
cs_logHeader.xsd	XSD
cs_logCurveInfo.xsd	XSD
cs_logData.xsd	XSD
cs_commonData.xsd