WITSML Well Log - Curve Information The curve name. More than one curve can have the same mnemonic but something like the array definition should be different between them. The curve classification obtained from a lookup in the vendors mnemonic catalog. Unit of measurement for the data values. Name alias for this trace. An empty string is the default representation of a null value for a curve (i.e., when the null value representation is not explicitly defined). If a null value is defined in the logCurveInfo, it overrides any null value specified at the logHeader level. An empty string is always a valid null value representation in the comma delimited list. An empty string is not a valid null value representation within a space delimited or base64 encoded array. Specifying a null value also makes it easier to transform data back to a legacy format without having to scan the data to insure that the null pattern does not exist in the data. True (true or 1) if this curve is a candidate to be a primary index. False (false or 0) or not given, indicates otherwise. An index curve should monotonically change when sorted on its own values (i.e., no duplicates). A pointer to the wellDatum that represents the values of this trace. This is only relevant for measured depths, vertical depths or elevations. Description of the curve. Offset of sensor from a downhole equipment vertical reference (the drill bit, for MWD logs; the tool zero reference for wireline logs). This element is only informative (log values are presented at actual depth, not requiring subtraction of an offset). Data source, could be tool name/id. Data density of sample in samples per length unit. State of trace data. Origin of trace data. Curve data type. For simple (non-array) traces, the data type of the curve data. For array curves (except Base64-encoded array curves), the data type of curve array element. For Base64-encoded arrays, the element data type is defined by encodingDef. If neither typeLogData nor encodingDef are given then 'Double' is assumed. Indicates that the channel is encoded using a Base64 representation of binary values, and defines the binary type of elements of the array. If absent and axisDefinition is given, implies space delimited values, whose elemental data type is given by typeLogData. Indicates that the curve is an array curve (i.e., multi-valued samples), and provides meta data by which an axis of the array can be understood. A separate definition is required for each axis of an N-dimensional array. Unique identifier for the curve. This value must be unique within the context of the wellLog. This value will be referenced by block curve descriptors.