OPC in Oilfield Operations
Schlumberger Limited is the worldâs largest oilfield services corporation, operating in approximately 80 countries, with about 70,000 people of 140 nationalities. Several of Schlumbergerâs Technology Centers selected OPC Toolkits from Softing, a leading provider of OPC components based near Munich, Germany, to develop OPC clients and servers. In particular, Schlumbergerâs Sugar Land Technology Center, located in Texas, has used Softingâs OPC Toolkit for C++ to develop an OPC server for its Smart Winch Control Terminal (SWCT). The SWCT is a proprietary software application that controls basic winch operations, provides safety awareness, and enables automated control and monitoring of the wireline inside a wireline-truck. Schlumberger selected Softingâs OPC Toolbox for implementing a customizable OPC Server because it enables the Design Team to concentrate on the project goal and not on learning the intricacies of Distributed Component Object Model (DCOM), Simple Object Access Protocol (SOAP), or other underlying Microsoft technologies.However, what is a wireline? In the oilfield industry the term âwirelineâ describes well service and evaluation operations that are conducted using a single-strand or multi-strand wire or cable. Although applied inconsistently, the term commonly is used in association with electric logging and cables incorporating electrical conductors. Similarly, the term âslicklineâ is commonly used to differentiate operations performed with single-strand wire or braided lines. In laymanâs terms, a wireline usually refers to a cabling technology used by operators of oil and gas wells to lower equipmentâwireline toolsâinto an existing well for maintenance, modification, repair or evaluation purposes. There are two parts to the equipment used for wireline services: the downhole tools (the parts that descend into the wellbore); and the surface equipment (the parts that help lower the tools and retrieve them).Wireline tools are typically cylinders from 1.125 in. to 5 in. (3 cm to 13 cm) in diameter. The total length of a wireline tool in most cases is more than can be handled in one piece. Thus, the tool is divided into different sections that are assembled at the well site. These sections may consist of cartridges, sondes, centralizers and adapters. Different measurements and tasks can be combined to make up a tool string. The total length of a tool string can range from 6 ft. to 100 ft. (2 m to 30 m) or more. Flexible joints are sometimes added in long tool strings to ease passage in the borehole, and to allow different sections to be centralized (in the center of the borehole) or eccentralized (against the bore hole wall). When on the wireline truck, the wireline is wound around a large (3 ft. to 6 ft. in diameter) spool. A winch is used to turn the spool and thus raise and lower the equipment into and out of the well. Lowering equipment on a cable down into an oil well sounds easy, when in fact it turns out to be a science in itself. Just consider the fact that a borehole may not run straight down but can change direction and run horizontally. In fact, current technology has extended the reach of multilaterals and horizontal wells to 10 miles or more, while enabling the equipmentâs placement in the reservoir with a precision approaching three feet. It is for the control of the winch electrical and hydraulic equipment that Schlumberger chose to use OPC-based technology.Very early in the development process of the SWCT software, Schlumbergerâs design team decided on OPC technology to standardize the data exchange mechanism. Using Softingâs OPC Toolkit, Schlumberger was able to quickly develop a customizable OPC Server that is able to communicate with the according actuators and sensors using both Ethernet and CAN-bus technology. Schlumbergerâs implementation supports Softingâs comprehensive line of industry-hardened CAN interface boards used to access CAN nodes on the wireline truck.The SWCT software helps the winch operator by providing the following functionalities: âą Controls winch operation during normal and automatic operation âą Monitors winch operations and records winch parametersâą Diagnoses control and sensor problems as required âą Performs MCM requests (Schlumbergerâs Minimum Configuration Maxis unit is a computer that can be considered the brain of wireline operation) âą Logs key data during operation. The graphical operator interface of the winch control terminal represents the OPC Client. Today, the complete system is installed on a single wireline truck, but the OPC system architecture includes the exciting possibility to remotely access the OPC Server on the wireline truck. This would allow for increased flexibility for wireline operations.OPC has become a widely accepted protocol for exchanging data with devices. This is one of the main reasons why Schlumberger chose to integrate OPC technology into its product line. Today, a user already has access to several OPC clients for visualization and other purposes that support OPC XML-Data Access (DA) and OPC DA. Specialized OPC Client applications, like the Smart Winch Control Terminal software, are easily developed by using software libraries like Softingâs comprehensive cross-platform OPC Toolbox suite, allowing the developer to concentrate on transmitting data and not on learning the intricacies of DCOM, SOAP, or other technologies.Softing, a member of the European Steering Committee of the OPC Foundation and author of the OPC Book, actively contributes to the success of OPC by providing high quality OPC products that enable our customers to stay in the lead. For more information on how Softing can assist you, please visit www.softing.us.
