The largest oil and gas company in India, Maharatna ONGC, contributes over 71% of the country’s domestic production. Crude oil is the raw material used by downstream companies like IOCL, BPCL, HPCL and MRPL (Last two are subsidiaries of ONGC) to produce petroleum products like Petrol, Diesel, Kerosene, Naphtha, and Cooking Gas LPG.
ONGC’s wholly-owned subsidiary ONGC Videsh Ltd. With 35 Oil & Gas assets spread over 15 nations, (OVL) is the largest international company in India.
Around 71% of India’s domestic production, or 1.26 million barrels of oil equivalent per day, is produced by ONGC. Of this, over 76% of crude oil produced is Light & Sweet.
ONGC is operating CTF / GGS at various fields of Mehsana Asset. The GGS processes the Crude oil/emulsion and associated gas produced from the oil wells. After the separation of the liquid and gas phase in the Separators, the liquid phase containing the crude oil emulsion is treated in the Heater Treaters. In this unit, the crude oil emulsion is broken and water is separated from the crude oil. This water is called Produced water or effluent and contains free oil, emulsified oil, and dissolved and suspended solids. GGS separates produced water which after treatment in the proposed PWTP for removal of oil, grease and suspended particles is to be routed for sub-surface disposal.
To achieve the suitable Produced Water, ONGC along with EPC Contractor HAL Offshore Constructed Produced Water Treatment Plant (PWTP) at Bechraji (2500 m3/day Capacity) & Sobhasan (1500 m3/day Capacity) at Mehsana Asset.
The scope of this project in Mehsana Asset is the construction of Produced water Treatment Plant including:
- Primary oil Separation (Surge & Wash Tank and CPI)
- Secondary Oil Separation (IGF)
- Tertiary Treatment – Final Polishing (NSF, Clarifier, PSF, Cartridge Filters and Ultra Filtration)
This project’s goal is to commission a PWTP based on the suggested setup procedure for treating produced water and preparing it for injection into effluent disposal wells.
The Hazard Identification (HAZID) Study is a brainstorming workshop with a multidisciplinary team to identify and assess potential health, safety, and environmental (HSE) hazards at the earliest practicable stage of the development of a project, plant, or plant modification. It is therefore likely to be the first formal HSE-related study for any new project or existing plant modification or improvement.
A structured, systematic review that identifies equipment that is being used in a way that it was not designed to be used and which might create hazards or operational problems. A multi-skilled team that examines piping and instrument schematics typically conducts HAZOPs. The flow, temperature, pressure, and other parameters of each pipeline and vessel are assessed for potential restrictions and deviations.
STUDY SCOPE AND FINDINGS
The HAZID and HAZOP Session for Produced Water Treatment Plant was facilitated by iFluids Chairman and supported by the scribe. Engineers from the ONGC, HAL Offshore and other members such as the design team and package vendors also participated in the studies.
In HAZID, Bechraji and Sobhasan PWTP facilities were considered individually under the study scope. The analysis of the entire facility based on the plot plan and other relevant HSE documents took 1 day with 8 hours of discussion.
For analysis, the entire installation was considered one system and the system underwent a brainstorming session considering 16 hazard categories based on the hazard identification checklist of ISO 17776:2016 (applicable guidewords for onshore facilities).
After the active discussion, the study team identified all possible hazards as per standard and their suitable barriers. Being an HSE consultant, iFluids proposed “9 Additional Safeguards” as a recommendation for each location to prevent the ultimate consequence and ensure the safe operation of facilities.
|Preventive Safeguard||Mitigative Safeguard|
|Bechraji – PWTP||2||7|
|Sobhasan – PWTP||2||7|
In HAZOP, a total of 111 P&ID’s (Bechraji – 55 and Sobhasan – 56) were considered under the study scope. The analysis of entire facilities based on as-built P&IDs (including package P&IDs) took 2 days with an average duration of 8 hours of discussion per day.
For analysis, the entire installation was divided into 16 nodes, which corresponds to 100% of facility. The Standard HAZOP methodology of BS IEC 61882:2016 was adapted for this brainstorming session. Each node undergoes the standard set of applicable deviations to identify the applicable causes based on P&ID and the respective consequences of the same; after that, suitable safeguards (barriers) that will prevent the consequence will be listed. If the barriers are sufficient as per discussion, the session proceeds to the next deviation. If not, suitable additional safeguards that could either be preventative or mitigative will be proposed to control the ultimate consequence.
After the active discussion, the study team identified all possible hazards as per standard and their suitable barriers. Being an HSE consultant, iFluids proposed “7 Additional Safeguards for Sobhasan PWTP and 6 Additional Safeguards for Bechraji PWTP” as a recommendation for each location to prevent the ultimate consequence and ensure the safer operation of facilities.
|Preventive Safeguard||Mitigative Safeguard|
|Bechraji – PWTP||3||3|
|Sobhasan – PWTP||3||4|