SY/T 6881-2024 Design code for water treatment and reinjectionengineering in highly hydrogen sulfide gas field English, Anglais, Englisch, Inglés, えいご
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ICS
E
Professional standard of the People's Republic of China
SY/T 6881-2024
Replaces SY/T 6881-2012
Design code for water treatment and rejection engineering in highly hydrogen sulfide gas field
高含硫气田采出水处理及回注工程设计规范
(English Translation)
Issue date: 2024-12-25 Implementation date: 2025-06-25
Issued by National Development and Reform Commission, P.R.C
Contents
1 General provisions
2 Terms
3 Basic requirement
4 Primary treatment process
4.1 Design capacity
4.2 Flash separation
4.3 Gas stripping
4.4 Soften with chemicals
4.5 Advanced oxidation
4.6 Membrane separation
4.7 Evaporation
4.8 Concentrated saltwater crystallization and drying
5 Auxiliary treatment process
5.1 Gas seal
5.2 Off gas disposal
5.3 Sludge disposal
5.4 Slope oil and wastewater recovery
5.5 Chemical dosing and storage
6 Pipeline transporation of produced water
6.1 General requirement
6.2 Transportation process
6.3 Transportation pipeline
6.4 Safety requirement
7 Reinjection of produced water
7.1 General requirement
7.2 Reinjection station
7.3 Reinjection pipeline
7.4 Reinjection well
8 Utility system and ancuillary facilities
8.1 Electrial
8.2 Heating and ventilation
8.3 Architecture and civil
8.4 Water supply, sewerage and fire fighting
8.5 Comision prevention
9 Monitoring and control
9.1 Monitoring
9.2 Automation and informatization
Explanation of wording in this code
List of quoted standards
Addition: Explanation of provisions
1 General Provisions
1.0.1 This code is formulated to implement the current relevant national laws, regulations, and policies in the design of produced water treatment and reinjection engineering for high hydrogen sulfide gas fields, to unify technical requirements, ensure quality, improve standards, and achieve advanced technology, economic rationality, safety and applicability, as well as convenient operation, management, and maintenance.
1.0.2 This code applies to the design of produced water treatment and reinjection engineering for new construction, expansion, and renovation projects of onshore high hydrogen sulfide gas fields and land-based high hydrogen sulfide gas fields in tidal zones.
1.0.3 In addition to complying with the provisions of this code, the design of produced water treatment and reinjection engineering for high hydrogen sulfide gas fields shall also comply with the current relevant national standards.
2 Terms
2.0.1 produced water separated from highly hydrogen sulfide gas field
Formation water separated from high hydrogen sulfide gas fields where the volume fraction of hydrogen sulfide in the natural gas is greater than or equal to 5%.
2.0.2 gas stripping
The process of introducing a gas (carrier gas) into water, allowing full contact between the water and the carrier gas, so that dissolved gases and volatile substances in the water transfer across the gas-liquid interface to the gas phase.
2.0.3 flash separation
The process of separating dissolved gases and volatile substances from a liquid under low pressure or atmospheric pressure conditions through pressure reduction.
2.0.4 off gas
Harmful gases that need to be discharged during the water treatment and reinjection process flow.
2.0.5 water reinjection in gas field
The surface process of reinjecting treated gas field produced water into the formation.
3 Basic Requirements
3.0.1 The design of produced water treatment engineering for high hydrogen sulfide gas fields (hereinafter referred to as "gas field water") shall be carried out in accordance with the approved overall plan for gas field surface construction and the provisions of the design commission or design contract.
3.0.2 The design of gas field water treatment engineering shall be based on unified demonstration, overall planning, and phased implementation, taking into account the water quality and quantity variation data during different development periods.
3.0.3 Gas field water may be disposed of by reuse, reinjection, or discharge. The specific method shall be determined after technical and economic comparison.
3.0.4 When treated water is used for reinjection into the gas field, its quality shall meet the water injection quality requirements of the target formation.
3.0.5 The gas field water treatment process shall be determined based on factors such as the hydrogen sulfide content in the incoming water, the intended use after treatment, and the sensitivity of the local environment, through experiments or similar project experience, after technical and economic comparison. The engineering design should comply with the following regulations:
1 Gas field water treatment should first undergo degassing treatment. Degassing treatment may use flash evaporation or gas stripping processes. When using the gas stripping process for degassing, oil and suspended solids should be removed first, followed by gas stripping.
2 For desalination treatment, reverse osmosis should be used to concentrate the raw water before evaporation. If surplus steam is available within the station or electricity prices are low, the evaporation process may also be used directly.
3 Near-zero discharge should adopt a combination or single treatment process of biological treatment, advanced oxidation, concentration, salt separation, and crystallization.
4 For reinjection, a closed buffer, sedimentation, gas stripping, and filtration treatment process should be adopted.
3.0.6 The collection, treatment, transportation, and reinjection of gas field water should be carried out in a closed system.
3.0.7 Treatment units processing gas field water containing hydrogen sulfide should be for nitrogen purging and sweeping.
3.0.8 The volume of the closed buffer facility shall be the sum of the volume required for gas field water buffering and the vapor space volume. The gas field water buffering volume shall be determined based on a calculated water flow retention time of not less than 30 minutes. The vapor space volume shall be determined based on a calculated water flow retention time of not less than 15 minutes.
3.0.9 If gas field water needs to enter the production wastewater treatment system of a natural gas processing plant, the gas field water shall undergo hydrogen sulfide removal treatment. After treatment, the hydrogen sulfide content in the gas field water shall not exceed 10 mg/L.
3.0.10 Gas field water treatment should be equipped with storage and disposal facilities for the of substandard water.
3.0.11 Waste liquid from corrosion inhibitor film coating treatment should be disposed of separately.
3.0.12 Natural gas discharged from gas field water treatment devices or units should be recovered and utilized. If recovery and utilization are not possible, it shall undergo harmless disposal.
3.0.13 Structures generating odorous gas sources shall be closed and equipped with off-gas recovery facilities; the collected off-gas shall be routed to an off-gas treatment unit for centralized treatment.
3.0.14 Lifting equipment, electrical equipment, doors, windows, walls, floors, etc., within the salt storage room shall all adopt anti-corrosion measures resistant to high salinity.
3.0.15 The explosion-proof requirements for electrical facilities and buildings in the gas field water treatment project shall be determined based on the division of explosion-proof zones.
3.0.16 Corrosion monitoring facilities should be installed on the raw water and treated water pipelines of the gas field water treatment station.
3.0.17 A wind direction indicator shall be installed at a conspicuous location in the gas field water treatment station.
3.0.18 In cold regions, anti-freezing and thermal insulation measures shall be taken for gas field water transmission pipelines and reinjection wellheads.
3.0.19 Site selection, general layout, and vertical planning shall comply with the relevant provisions of the current national standards "Code for design of general plan of petroleum and natural gas engineering" SY/T 0048 and "Code for fire protection design of petroleum and natural gas engineering" GB 50183.
3.0.20 Warning signs for occupational disease hazards at high-toxicity hydrogen sulfide workstations shall be posted at locations such as hydrogen sulfide-containing water storage tanks, sour gas field water stripping units, and off-gas treatment units. The setting of warning signs shall comply with the relevant provisions of the current national standard "Occupational hazard warning signs in the workplace" GBZ 158.
