3.5 “Growing” Data Objects and the New “Part” Object

Drilling and logging result in data objects that grow over time and as such WITSML refers to these as growing data objects, which are characterized by:

• Relatively large number of occurrences of recurring data that is indexed to time or depth.
• Additional occurrences of recurring data that are inserted (or updated) over time (which is what causes the data object to grow).

Growing data objects include: trajectories, logs, and wellbore geology (mud logs in v1.4.1). WITSML v1.4.1 included special instructions for how to manipulate and manage these objects with a SOAP API.

The Energistics Transfer Protocol (ETP) was designed to address many of the issues with the former API, so that data can be streamed in real time. To accommodate this capability required a change in the WITSML data model, namely the creation of a “part” sub-object for any object that you would want to stream data for, which includes all growing objects.

Figure 3.5-1 shows a portion of the UML model for the interpreted geology interval object (which is related to the wellbore geology object) and part_interpretedGeology interval which is used to stream data. Note that parent objects of part objects have a growing status field to indicate whether the object is active, closed, or inactive.

Figure 3.5-1 Objects named “part_” (circled above) are required for streaming of data using ETP.