Impact Of CPC Systems On Offshore Operations
Authors: Obadiah Vic , Rainwater D.F. 
Published: December 2007

Post automation impact on Conoco's offshore producing operations has been very positive. Many producing operations has been very positive. Many benefits have been realized during normal daily operations. The hurricane mode concept in offshore operations was introduced as a result of the CPC systems reliability. Operating crews are evacuated and all automated platforms continue to produce unmanned when a tropical storm or a produce unmanned when a tropical storm or a hurricane approaches our facilities. Our offshore operations have incorporated appropriate staffing and procedures to maximize the utility of their CPC systems.

HISTORY AND DESCRIPTION OF OPERATIONS

Conoco's Computer Production Control (CPC) System has been in operation at the New Orleans' Offshore Division since the early 70's. Our objective is the continued operation of our offshore production facilities with emphasis on personnel safety and protection of the environment personnel safety and protection of the environment while producing maximum allowable rate at minimum cost. Our CPC system has been an extremely valuable instrument in getting us closer to that goal.

The system covers five fields producing oil and gas with over 370 well completions monitored through 38 Remote Terminal Units (RTU's) under the CPC operation. The system is interconnected to the CPC computer through a unique microwave loop representing the communication media as shown on Figure 1. The microwave loop starts at the computer center in Conoco's office in Algiers, east of downtown New Orleans, Louisiana. One leg of the loop extends to a microwave station at Grand Isle through an intermediate station at Lafitte Village. The second leg extends to Venice with intermediate stations at Myrtle Grove and Home Place. Offshore repeater stations located on several production platforms connect the Grand Isle leg to the Venice leg thus completing the communication loop.

Underwater cables tie together platforms with RTU's into certain platforms equipped with the microwave stations. This arrangement permits two or more RTU's to communicate to the CPC computer through one microwave station utilizing up to eight separate channels. The looped design of the microwave system adds a degree of fail-safe operation as well as flexibility. If a microwave failure occurs at any one offshore station, all other stations are within reach by communicating down both legs of the loop.

Conoco's New Orleans automated production system performs the normal scanning, controlling, and data acquisition (SCADA) functions of a typical CPC system. The SCADA activity would include the monitoring and alarming, when appropriate, of liquid levels, pressures, temperatures, and the ON or OFF status of major equipment such as generators and compressors. Control functions would open or close valves, shut-in wells by closing the master and wing valves, divert wells for periodic testing, and start or stop functions of hurricane timers and compressors. Data acquisition which provides fluid flow rates and volumes is achieved through either the direct readout of digital output meters or through calculations from analog signal with analog-to-digital convertors on the RTU'S.

Thus, the CPC system provides the operating personnel with the ability to attain constant personnel with the ability to attain constant surveillance of production, testing, gas-lift injection, gas compression, water disposal, power generation, and overall facilities performance. Offshore crews' quarters are equipped with teletype terminals connected to the CPC computer in New Orleans. Alarm conditions are transmitted to these terminals as they occur. After working hours, field operating personnel are dispatched from their quarters to implement any corrective measures if urgent action is deemed necessary as a result of critical alarms. The system has the capability to remotely control the producing operation during hurricanes.