WITSML 1.3: The Data Transfer Standard for Petroleum Industry

Introduction

The oil and gas industry has consistently strived to optimize operations, enhance safety, and reduce costs through the effective utilization of data. The unprecedented volume of data generated in drilling, well completion, and production operations has created significant challenges in data acquisition, storage, exchange, and analysis. In the past, the absence of a unified standard for data exchange led to numerous issues, including data format inconsistencies between different software and hardware, the need for developing expensive custom interfaces, and difficulty in achieving comprehensive information integration.

In response to this critical need, initiatives to develop open data exchange standards were proposed. One of the most important of these initiatives was the emergence of the WITSML (Web-Enabled Information Transfer Standard Markup Language) standard, developed by the Energistics consortium (a global non-profit organization comprised of oil and gas companies, service and software providers, and universities). The primary goal of WITSML was to provide a web-based solution for the exchange of real-time and historical data related to drilling, completion, and production operations.

Version WITSML 1.3, introduced in the early 2000s, was a key step in this direction. By defining a set of XML schemas and web-based communication protocols, this version enabled the exchange of structured data between different systems, helping companies move beyond traditional data silos toward more integrated and intelligent operations. This article will provide a detailed review of the technical and practical aspects of WITSML 1.3.

Fundamental Principles and Architecture of WITSML 1.3

History and Evolution

The roots of WITSML trace back to the DART (Drilling and Real-time Operations) project, initiated by BP, Statoil, and Shell in the late 1990s. The project's goal was to create an industry standard for drilling data exchange. The results of this project were transferred to Energistics, and the organization took on the responsibility of developing and maintaining the standard. WITSML 1.3, followed by WITSML 1.3.1.1, were the initial and significant versions that laid the groundwork for subsequent capabilities.

Data Structure and XML Schema

At the heart of WITSML 1.3 is the use of XML (Extensible Markup Language) to define data structures. Data is organized into "Data Objects," each representing a specific entity in drilling or well operations. The XML schemas (XSD) precisely define the structure and data types allowed for each of these objects. These schemas ensure the reliability and validity of the exchanged data.

Some of the most important data objects in WITSML 1.3 include:

• Well: General information about the well (name, location, type).
• Wellbore: Information about the drilled paths within a well (deviated paths, depths).
• Log: Data recorded during or after drilling (e.g., well logging data, geophysical values at depth).
• Trajectory: Wellbore survey data, including depth, azimuth, and inclination.
• BHA Run (Bottom Hole Assembly): Information about the downhole tool assembly.
• Fluids Report: Data related to drilling fluids.
• Message: Operational messages and events.
• And many other objects such as Casing, Cement Job, MudLog, and etc.

The use of Unique Identifiers (UIDs) for each data object allows for precise referencing and linking between different objects, contributing to information integrity.

Communication Protocols and API

WITSML 1.3 uses Web Services based on the SOAP (Simple Object Access Protocol) for data exchange. This protocol enables communication between heterogeneous systems over HTTP/HTTPS. The WITSML 1.3 API (Application Programming Interface) defines two main interfaces:

1. The STORE Interface: This interface is used for storing, retrieving, updating, and deleting data. Key functions include:
   • WMLS_AddToStore: Add one or more data objects to the WITSML database.
   • WMLS_DeleteFromStore: Delete data objects.
   • WMLS_GetFromStore: Retrieve data objects based on a query.
   • WMLS_UpdateInStore: Update existing data objects.
   • WMLS_GetCap: Get the capabilities of the WITSML server.
2. The PUBLISH Interface: This interface was designed for real-time (or near real-time) data publication. However, due to challenges related to firewalls and the synchronous nature of the SOAP protocol in operational environments, this interface was not widely adopted and was generally not successful. This issue became the motivation for developing more advanced communication protocols in later versions.

The SOAP and XML-based architecture provided a standard and understandable approach for developers, greatly assisting in interoperability between different platforms.

Applications and Advantages of WITSML 1.3

Practical Applications

WITSML 1.3 found widespread use in various parts of upstream oil and gas operations and helped companies improve their processes. Some of its most important applications include:

• Real-time Drilling Operations Monitoring: The real-time transfer of drilling data (such as mud parameters, depth, rate of penetration, pressure, and temperature) from the rig to operations and engineering centers allowed for continuous monitoring and informed decision-making.
• Drilling Optimization: Analyzing real-time and historical data helped engineers optimize drilling performance, reduce risks, and prevent incidents.
• Reporting Automation: Automating daily and weekly reporting processes increased accuracy and speed by reducing the need for manual data entry.
• Systems Integration: Enabling data exchange between different vendor systems (such as well data management systems, geological software, drilling fluid engineering systems) contributed to informational and operational integration.
• Analysis and Prediction: The collection of standardized data provided a suitable foundation for advanced analytics, modeling, and machine learning algorithms to predict problems and optimize processes.

Key Advantages

The implementation of WITSML 1.3 brought several benefits to the industry:

• Standardization: The most significant advantage was providing a global standard for data exchange that eliminated the need for custom interfaces.
• Increased Interoperability: Enabled communication and data exchange between software and hardware systems from different vendors.
• Access to Real-time Data: A dramatic improvement in the speed and efficiency of data transfer from the rig to central offices and vice versa.
• Reduction of Data Silos: Created a unified view of operations by aggregating data from various sources.
• Improved Decision-Making: Fast and easy access to accurate, up-to-date data led to better and faster decisions.
• Increased Operational Efficiency and Safety: With better monitoring and the ability to respond faster to conditions, operational efficiency increased and the risk of incidents decreased.

Limitations and Challenges

Despite its significant advantages, WITSML 1.3 also faced limitations and challenges that led to the development of subsequent versions and complementary standards:

• PUBLISH Interface Limitation: As mentioned earlier, the PUBLISH interface, designed for real-time data exchange, failed to perform well due to firewall issues and the synchronous nature of the SOAP protocol. This highlighted the need for new communication protocols that could more effectively manage high-volume, real-time data streams.
• Interoperability Problems Between Implementations ("Dialects"): Despite being a standard, different vendor implementations sometimes came with their own "dialects," leading to minor inconsistencies and the need for specific configurations. This occurred due to different interpretations of the XML schema or the addition of proprietary fields by vendors.
• Immaturity and Complexity: In its early stages, WITSML 1.3 was still maturing and had its own implementation complexities. This was due to the novelty of the concept of standardizing real-time data in the industry.
• Issues with Non-standard Data: Despite the definition of many data objects, some specific and non-standard data might require custom solutions.
• Time and Depth Data Management: Ensuring the consistency and accuracy of time- and depth-dependent data across different systems remained a challenge.

The Evolution of WITSML and its Relationship with Energistics Standards

WITSML 1.3 vs. Newer Versions

The limitations of WITSML 1.3, especially in the area of real-time data exchange, became the motivation for developing later versions of the standard. The main subsequent versions include:

• WITSML 1.4.1.1: This version introduced improvements to the data schemas and API capabilities, including the addition of the ChannelSet object, which allowed for grouping log data. However, it still used the SOAP protocol, and the Publish/Subscribe issues remained.
• WITSML 2.0 and later versions: The most significant change in WITSML 2.0 was the transition from SOAP to ETP (Energistics Transfer Protocol). ETP is a modern and more efficient WebSocket-based protocol designed for higher-performance exchange of large-volume, real-time data. WITSML 2.0 also revised the data schemas and moved towards a more integrated data architecture with other Energistics standards.

While WITSML 1.3 played a vital role in initiating standardization, newer versions were developed with a focus on improving efficiency, interoperability, and compatibility with the industry's growing needs for real-time and big data.

WITSML, PRODML, and RESQML

WITSML is just one of the main standards developed by Energistics for the "Digital Oilfield." The three key Energistics standards are:

1. WITSML: Focused on data from drilling, completion, and well interventions operations.
2. PRODML (Production Markup Language): Focused on production and operations data, including data from producing wells, surface facilities, and fluid flow.
3. RESQML (Reservoir Markup Language): Focused on reservoir data, including geological models, reservoir models, and simulation data.

These three standards are complementary and together provide a comprehensive framework for managing data throughout the lifecycle of oil and gas assets. The ultimate goal is to create a fully integrated operational environment where data flows smoothly and in a standardized manner across different disciplines and operational phases.

Conclusion

WITSML 1.3 is a milestone in the history of the digitalization of the oil and gas industry. By introducing an XML and web services-based approach for drilling data exchange, this standard made great strides in overcoming the challenges of data incompatibility and information silos. Despite its limitations, particularly in true real-time exchange, WITSML 1.3 provided the necessary foundation for the emergence of more advanced and efficient solutions in later versions and complementary Energistics standards.

The importance of WITSML 1.3 lies not only in its technical capabilities but also in its shift in the industry's mindset toward standardization, integration, and optimal data utilization. Today, while it has been replaced by newer versions and protocols like ETP, the legacy of WITSML 1.3 in establishing a solid foundation for data exchange in the era of the Digital Oilfield remains enduring and valuable.