Wellsite Information Transfer Specification
The WELLSITE INFORMATION TRANSFER SPECIFICATION (WITS) is a communications format used for the transfer of a wide variety of wellsite data from one computer system to another. It is a recommended format by which Operating and Service companies involved in the Exploration and Production areas of the Petroleum Industry may exchange data in either an online or batch transfer mode.
WITS is a multi-level format which offers an easily achieved entry point with increasingly flexible higher levels. At the lower levels, a fixed format ASCII data stream is employed, while, at the highest level, a self-defining customizable data stream is available.
A WITS data stream consists of discrete data records. Each data record type is generated independently of other data record types and each has a unique trigger variable and sampling interval. The rig activity usually determines which records are applicable at any given time such that only appropriate data is transmitted.
WITS also incorporates the means for a remote computer system to send instructions to the sending system in order to set or change certain parameters, including the type of data transmitted and the interval for transmission.
As well as specifying a format for data transmission, WITS also defines a basic set of pre-defined records to which user-defined record types may be added.
WITS has been used extensively for a number of years by working for many operators around the world to facilitate information-sharing and to provide data to remote monitoring facilities.
Over the years many Operating and Service companies developed proprietary formats for electronic data exchange. When a new working relationship was established between a Service company and an Operator, new software often had to be written, followed by extensive testing and debugging before the data collection and analysis systems of the two entities could communicate with one another correctly. This often led to problem start-ups with the resulting loss of time and data. The ongoing development and maintenance of these formats represented a significant expenditure.
The cost and complexity of format matching and modification often led to a reluctance on the part of some Operators to get involved in this type of service, and a great deal of rig data, which might have been extremely useful in rig performance evaluation, drilling monitoring and control, and formation evaluation while drilling, was often not collected or was not readily available to decision makers.
In an attempt to resolve this information transfer problem, the Wellsite Information Transfer Specification was established .
A number of Operating and Service company representatives with wide experience in the areas of computer software system development, geology and drilling engineering formed the first workgroup to look into the needs of the industry in this area. All were familiar with the problems associated with the profusion and mismatch of rig data formats.
To ensure that any format proposed was both complete and acceptable to the industry as a whole, a vigorous effort was made to involve representatives from as many Operating and Service companies as possible. This effort included correspondence with companies operating in Europe and Asia as well as the United States.
The goal of the work group was broad but concrete:
"To define the format and information content of the data stream transmitted from a wellsite to a central site by telecommunications facilities or hard media".
To minimize omissions in the format, a major effort was made to obtain an inventory of data items monitored or collected at the wellsite in the following areas:
The WITS Steering Group is also a member of the API Petroleum Information Data Exchange (PIDX). The API-PIDX WITS User Group exists to promote the format, respond to questions of interpretation, and to investigate ways of enhancing the format to meet new requirements in the future.
WITS Transmission Levels
The following summarizes the various levels of WITS:
Twenty five Pre-Defined Records have been identified, covering, among other areas, drilling, geology, directional work, MWD, cementing and testing. At Level 1, these data records, generated at varying times and under varying rig conditions, are constructed and placed in the data communications channel.
No LIS record types besides Data Records are used at this level. Each of the 25 Pre-Defined Records has a fixed size in bytes. However, each contains designated 'spare' channels for limited customization. The Pre-Defined Records are:
|1||General Time-Based||Drilling data gathered at regular time intervals|
|2||Drilling - Depth Based||Drilling data gathered at regular depth intervals|
|3||Drilling - Connections||Data gathered at drilling connections|
|4||Hydraulics||Hydraulics data gathered while circulating|
|5||Trip - Time||Tripping data gathered while running in/pulling out|
|6||Trip - Connections||Tripping data gathered at tripping connections|
|8||MWD Formation Evaluation||MWD Formation Evaluation data|
|9||MWD Mechanical||MWD Mechanical data|
|10||Pressure Evaluation||Pressure Evaluation data|
|11||Mud Tank Volumes||Mud Tank (Pit) Volume data|
|12||Chromatograph Cycle-Based||Chromatograph Cycle data|
|13||Chromatograph Depth-Based||Chromatograph data averaged over depth intervals|
|14||Lagged Mud Properties||Mud Property data based returns depth increments|
|15||Cuttings / Lithology||Cuttings Lithology and related data|
|16||Hydrocarbon Show||Hydrocarbon Show related data|
|17||Cementing||Well Cementing operations data|
|18||Drill Stem Testing||Well Testing operations data|
|19||Configuration||Drillstring and Rig Configuration data|
|20||Mud Report||Mud Report data|
|21||Bit Report||Bit Report data|
|23||Well Identification||Well Identification data|
|24||Vessel Motion / Mooring Status||Vessel Motion and Mooring Status data|
|25||Weather / Sea State||Weather and Sea State data|
Participants in the steering group include:
Operating companies for wells on which WITS services have been provided
Service companies with experience providing WITS services
|Baker Hughes INTEQ||Anadrill||Sperry Sun||Martin Decker TOTCO|
Countries/areas where WITS services have been provided
|Australia||Papua New Guinea||Indonesia||Venezuela||South Africa||Egypt|