Pre-feasibility Report

Transcription

1 Pre-feasibility Report Environmental Clearance for Capacity Enhancement of ADB Gas Collecting Station (GCS) from existing 2.2MMSCMD to 2.71 MMSCMD and ETP of capacity 100m3/day OIL AND NATURAL GAS CORPORATION Ltd. TRIPURA ASSET Page 1 of 8

2 1.0 Introduction The discovery of gas in Tripura region in 1970s raised the hope for development of this remotely located state, which received further fillip in when gas production commenced in Tripura. Over the years, 11 structures have been probed through exploratory drilling by ONGC, out of which commercial gas has been discovered in 8 structures viz Baramura, Rokhia, Agartala Dome, Gojalia, Tichna, Sonamura, Kunjaban & Sundalbari. Unfortunately, poor infrastructure and absence of adequate industrial development did not allow this natural resource to be fully utilized for strengthening the economy of the State. Thus, this vital source of energy remained under-utilized. With a view to monetize the idle gas reserves and improve the power scenario of the North- East, ONGC conceptualized setting up Mega Power Plant of MW capacity through a joint venture company viz. ONGC Tripura Power Company (OTPC) at Palatana in Palatana is located at a distance of about 60 km from Agartala City. The requirement of gas for this plant was estimated to be around 2.65 MMSCMD and the supply was to be ascertained at least for 15 years. Subsequently, keeping in view the latest gas demand scenario in the state, ONGC Management has recently strategized to produce and supply 5.0 MMSCMD from the Tripura state. 1.2 Proposed Project: This project includes the following activities: i. Capacity Enhancement of Agartala Dome GCS to 2.71 MMSCMD ii. Effluent Treatment Plants (ETPs): ETP for handling 100 m3/day at ADB GCS 2.0 Capacity Enhancement of Agartala Dome GCS to 2.71 MMSCMD Agartala Dome GCS, a gas installation of Tripura Asset currently supplies gas to OTPC, Palatana via ONGC operated trunk line and to NEEPCO via GAIL s trunk lines. The GCS also supplies gas to the Piped Natural Gas (PNG) network of Agartala city and CNG stations. Currently the designed capacity of GCS is 2.2 MMSCMD of Gas, 52.3 m3/day of condensate and 52.8 m3/day of produced water. The study conducted shows the latest production profile indicates peak production of 2.71 MMSCMD of gas. The technical study envisages adequacy check of the existing facilities, identifying bottlenecks in the GCS and suggesting remedial measures for handling additional 0.51 MMSCMD gas. Page 2 of 8

3 S. Equipment No. 1 HP Separator (V-101) 2 MP Separator (V-102) 3 Test Separator (V-107) 4 Gas Scrubber (V-103) 5 Condensate Separator (V-104) 6 Condensate Stabilizer (V-105) 7 Condensate Storage Tank (T-101 A/B) Existing Capacity 2.2 MMSCMD Proposed Capacity 2.7 Size (Dia x H in mm) MMSCMD 1500 x 3350 Capacity can be enhanced by diverting the high pressure wells 1500 x 3400 presently flowing in HP separator to MP separator. In case of the entire peak gas coming under MP separator, HP separator can be operated with reduced pressure x x 3000 Additional scrubber of 0.51 MMSCMD capacity required 1000 x x m 3 x 2 = 150 m 3 Safe filling cap= 0.8x150= 120 m 3 8 Condensate transfer pump (P 101 A/B 9 Effluent water stabilizer (V-106) 10 Gas Filter F-1010 A/B 11 Bath Heater (E 101 A/B Capacity 12 m 3 /hr Differenetial pr. = 3.0 ksc 900 x mmscmd Required additional filter of 0.51 MMSCMD capacity Heat Duty : HP Bath Heater = mm Kcal/Hr Test Bath Heater = mm Kcal/Hr 12 Flare Header 20 inch Dia 13 Flare KOD 2200 x 4500 Installation of another flare KOD in parallel with existing one is necessary 14 Water Seal Drum Dia = 2000 mm Water Depth = 1000 mm Seal leg Depth = 300 mm 15 Flare Stack & Tip Stach Height = 35 m Stack Dia = 24 inch Tip Type Pipe; Tip Length = 3 m 16 Flare KOD Cond Capacity = 12 m3/hr Pump (P108 A/B) Delineate a sterile zone of 40 m radius from stack base Page 3 of 8

4 Based on the study, the constraints in processing additional 0.51 MMSCMD gas can be resolved by installing another scrubber, filter and flare knock-out drum. Cost of the Project is estimated as 5.0 Crore. HP and MP Separator: Capacity can be enhanced by diverting the high pressure wells presently flowing in HP separator to MP separator, thereby limiting the maximum gas to be handled in either separator to 2.2 MMSCMD. In case of the entire peak gas coming under MP separator, HP separator can be operated with reduced pressure. Test Separator is having designed capacity of 0.5 MMSCMD and is adequate for testing any single well from additional wells indicated in the profile. Scrubber: Installation of another scrubber in parallel with existing one for handling additional 0.51 MMSCMD gas is required. Filter: Additional filter of 0.51 MMSCMD capacities downstream of the additional scrubber is required. Flare Knock-Out Drum (KOD): Installation of another flare KOD in parallel with existing one is necessary for handling additional emergency load of 0.5 MMSCMD gas. 3.0 Effluent Treatment Plant (ETP) Moreover, based on the liquid production profiles furnished by study, the above GCS shall also be capable of handling the process water and condensate. Based on the expected liquid profile, m3/d water is expected at ADB GCS. The facilities envisaged in ETP are to treat the effluent for the Sub-surface disposal. Cost of the Project is estimated as Crore. Sl. Envisaged Profile of Combined ETP Processing capacity Name of Field No. Produced Water (M 3 /day) (M 3 /day) 1 Agartala Dome M 3 /day 4.0 Environment and Safety Management The environmental impact and safety issues of the proposed locations are briefly discussed. At the outset it is brought out that all existing installations of Tripura Asset have been holding QHSE accreditation (Quality Health, Safety & Environment Management System i.e. QMS-ISO 9001, EMS-ISO & OHSAS 18001) by third party certification body since March, 2005 and are timely renewed. 4.1 Environment Protection Measures Page 4 of 8

5 The proposed project is De-bottlenecking study for handling additional gas at ADB GCS, Tripura Asset. There is no requirement of extra land for this project. The construction completion schedule is 15 months. The major part is construction of concrete foundation and assembling of instruments. The environment protection measures already in place are sufficient. No deviation from the current environmental condition is envisaged. The principal pollutants will comprise of Particulate Matter (PM), Sulphur and Nitrogen Dioxides (SO2 and NO2) and other Hydrocarbons (HC). The study conducted in Oct 2016 of the area shows that the ambient air quality resembles rural settings where the parameters monitored (PM2.5 = 27µg/m3, PM10 = 42µg/m3, NO2 = 37µg/m3, SO2 = 6.2 µg/m3) does not deviate from National Ambient Air Quality Standards. The ambient mean values of methane and non-methane hydrocarbons are 2.86 ppm and NIL, respectively. The ambient noise measured does not exceed the stipulated daytime and night time Standard for Residential Areas. 4.2 Emergency Preparedness Major emergency situations during operations are fire and gas leakage. Emergency control measures are defined for each situations. Fire/smoke detectors, gas detectors are provided for early detection of fire in GCS. Water sprinkler and deluge system, automatic dry chemical powder and foam systems are provided to control fire. Hi-Lo Safety valves installed on wells automatically close the well in the event of pipeline failure, thus limiting the quantity of any gas leakage.inspections of pipelines are regularly carried out to ensure their integrity and protect against corrosion. Gas corrosion inhibitor is dosed to pipeline gas to be transported over long distances. Disaster Management Plan: To minimize the consequences of disaster due to the situations mentioned above, disaster management plans (DMP) have been prepared. Drills and Exercise: Regular drills are carried out in GCS installations to ensure that persons are familiar with their emergency duties and can respond effectively. 5.0 Project Investment The total cost including cost of ADB GCS up gradation and ETP construction of 100m3/day is approximately Rs. 26 Crores. Page 5 of 8

6 Process Flow Diagram of Effluent Treatment Plan Page 6 of 8

7 Page 7 of 8

8 Layout showing new construction area within the existing GCS area Area for Proposed ETP Page 8 of 8