Distributed control system (DCS) is available in most of the compressor stations of cross-country pipeline systems. Programmable logic controller (PLC) is used in all the intermediate pigging (IP) stations/sectional valve (SV) stations to collect the field data and to control the remote actuated valves. This paper presents how DCS or PLC can be used for cathodic protection of gas pipelines. Virtual instrumentation (VI) software is used here for simulation and real-time implementation purpose. Analog input channels available in DCS/PLC can be used to measure pipe to soil potential (PSP) with the help of half-cell and voltage transducer. Logic blocks available in DCS can be used as low selector switch to select the lowest PSP. Proportional-integral (PI) controller available in DCS/PLC can be used for taking the controlling action. PI controller output varies the firing angle of AC phase controller. Phase controller output is rectified, filtered, and fed to the pipeline as cathodic protection current. Proposed scheme utilizes existing infrastructure to control pipeline corrosion.

A robust virtual instrumentation based fuzzy incremental corrosion controller is presented to protect metallic gas pipelines. Controller output depends on error and change in error of the controlled variable. For corrosion control purpose pipe to soil potential is considered as process variable. The proposed fuzzy incremental controller is designed using a very simple control rule base and the most natural and unbiased membership functions. The proposed scheme is tested for a wide range of pipe to soil potential control. Performance comparison between the conventional proportional integral type and proposed fuzzy incremental controller is made in terms of several performance criteria such as peak overshoot, settling time, and rise time. Result shows that the proposed controller outperforms its conventional counterpart in each case. Designed controller can be taken in automode without waiting for initial polarization to stabilize. Initial startup curve of proportional integral controller and fuzzy incremental controller is reported. This controller can be used to protect any metallic structures such as pipelines, tanks, concrete structures, ship, and offshore structures.

Wellhead control panel ensures safe operation of Oil /Gas well operations. Digitalization of wellhead control panels helps in reducing the downtime. Distributed Control System ( DCS) can be used for collecting the wellhead control panel data and to perform panel health assessment. It triggers maintenance request / short messaging service ( SMS) once it identifies fault / trip. This paper analyses on how digitalized well head control panel maintenance can be carried out and how it reduces well down time considerably.

Hydrogen sulphide (H2S) gas is one of most poisonous gas associated with oil and gas production. Gas release in wellhead and crude oil product transfer flow line has to be detected at the earliest to save human life and asset. When the oil wells are spread over hundreds square kilometers, it is not an easy task to monitor H2S release. H2S gas detection solution should be economical. In the desert, there will be hundreds of oil and gas wells exist; typically oil wells data is available in oil control room and gas wells data is available in gas control room. At present sharing of H2S detector status between these control rooms does not exist. All the sour gas wells are equipped with local H2S monitoring and well tripping mechanism on gas detection. Objective of this paper is to detect any H2S gas release in well heads and transfer lines in an economical way. The entire field mounted gas detectors status is collected in centralized control room and detector location mapping is done. Weather monitoring station information such as wind direction, wind speed, etc., is populated in the same page. In unrepresented vulnerable locations such as trunk roads, security check post, cattle firm, etc., standalone solar powered H2S detectors are installed and its signal is connected to RTU. RTU sends signal through GSM modem to Field Data Integration system; which facilitates centralized monitoring of available H2S detectors status. Field data integration system collects gas detectors status in oil control room and gas control room through OPC server and populates are the detectors status in single page; which facilitates emergency handling. This paper presents various types of H2S detection technology used in upstream oil industry and their response time. It also talks about recent technological advancement in H2S detection.