GB/T 43936-2024Technical specification for land reclamation and ecological restoration of petroleum and natural gas projects (English PDF)

3 Terms and definitions

3.1 The central term is printed with the Chinese heading for land reclamation and ecological restoration of oil and gas projects and the English term mine land reclamation and ecological restoration. It is defined as the activity of taking preventive and restorative measures, relying on artificial support and guidance and on natural recovery capacity, against the damage to the geological environment, the damage to land and the damage or degradation of the ecosystem caused by the extraction of oil and gas resources, so that the geological environment of the production and construction area becomes safe and stable, the damaged land is reclaimed and used and the functions of the ecosystem are restored or improved. A note gives the abbreviated Chinese form, rendered here as reclamation and restoration.

3.2 natural restoration: stopping human disturbance of the ecosystem so as to lighten the load and pressure on it and relying on its self-regulating and self-organising capacity to let it succeed, renew and recover naturally in an ordered direction. The source is given as TD/T 1070.1-2022, 3.2.

3.3 landscape construction: adjusting and optimising the structure and allocation of land resources, water resources, biological resources and the human settlement environment from the scale of watershed hydrology and landforms, following the integrated protection and restoration of mountains, waters, forests, farmland, lakes, grassland and sand, and taking full account of the point, line, surface and network landscape integration of the oil and gas project area, so as to build an ecosystem in harmony with the surrounding landscape.

3.4 to 3.6 well field: the working site for drilling, exploration and extraction of oil and gas, divided by the nature of the land use into temporary land and construction land; road: the roads built for exploration, extraction, processing, transport and patrolling of oil and gas; pipeline: the pipes used to convey oil, gas and water and connecting pumps, valves or control systems, including buried cable and electric line ducts serving the production and construction of the project. All three cite TD/T 1031.5-2011, modified.

4 Overall requirements and basic principles

4.1 The work shall follow the concept of integrated protection and restoration of mountains, waters, forests, farmland, lakes, grassland and sand, and keep to the policy of conservation first, protection first and natural recovery as the main approach. Through mitigation and protection, prevention and control and reclamation and restoration measures, reclamation and restoration and mineral resource extraction are to be planned together and implemented in a coordinated way, damaged land is to be reclaimed and used in good time, and the diversity, stability and sustainability of the ecosystem of the project area are to be restored and raised, promoting green mine construction and the harmonious coexistence of people and nature.

4.2.1 Protection first and control at source. Following the principle of protection during development and development during protection, production and construction processes are to be optimised and reasonable prevention and control measures adopted so as to reduce the damage to the geological environment, to land and to vegetation caused by resource extraction; where damage to land and vegetation cannot be avoided, reclamation and restoration are to begin in good time once the geological safety hazards have been removed.

4.2.2 Unified planning and coordinated implementation. Reclamation and restoration work is planned as a whole, resource extraction and the planning and construction of reclamation and restoration are carried out at the same time so that reclamation and restoration proceed alongside extraction over the whole life cycle, and reclamation and restoration advance together with green mine construction, protection, prevention and control and reclamation measures being taken at the same time.

4.2.3 Combination of artificial guidance and natural recovery. Following the principle of using land for cultivation, forest, grassland, wetland, wasteland or sand as suits it, damaged land is brought to a usable state and ecosystem functions are restored by engineering, biological and chemical means; the direction and process objectives of artificial guidance are to be clear, the early artificial support reasonable, and nature is to be respected and used so that damaged land and ecosystems return to a virtuous circle as soon as possible.

4.2.4 Landscape harmony and functional improvement. Given that oil and gas projects have many scattered points, cover a wide area and use small individual parcels, the direction, measures and standards of reclamation and restoration are determined, on the basis of alignment with territorial spatial planning and mineral resources planning, in accordance with the original land use type or the same land use type in the surroundings; the restored ecosystem is to be in harmony with the surrounding ecosystem, biodiversity protection is implemented over the whole life cycle and the recovery gap is to be narrowed as far as possible.

4.2.5 Public participation and monitoring throughout. Contact with interested parties is to be maintained throughout the life cycle of development, use, protection and restoration, giving all of them meaningful opportunities to take part so as to ensure the fairness and inclusiveness of the project; local traditions, customs and social expectations are to be respected; and monitoring throughout is to be carried out, evaluating and analysing the ecological problems arising during resource development and the effects of reclamation and restoration, the plan being revised or adjusted according to the monitoring and evaluation results.

6 Basic investigation and problem identification and diagnosis

6.1.1 The investigation covers natural conditions (geographical position, climate, hydrology, topography and landforms, regional geology, soil and vegetation, surveyed over the project area and its surroundings); socio-economic and cultural conditions (the agricultural population, cultivated land per head, net income per head and agricultural production of the last three years, and cultural resources such as historic monuments, religious sites, protected historical and cultural areas, geological heritage reserves and scenic areas); production and construction conditions (extraction history and present state, extraction range, extraction method, production process, production scale, service life or remaining life and extraction plan); the present state of the geological environment, surveyed by land unit such as well field, road and pipeline and their surrounding area of influence, making clear the type, distribution, scale and features of the problems; land use, making clear the position, area, degree and type of the land already damaged and, for areas already reclaimed, the measures, effects and investment involved; and ecological conditions, covering protected areas, world natural heritage, ecological conservation red lines, protected species, ancient and famous trees, vegetation cover and biodiversity, and the types, numbers and distribution of animal populations. Where a project crosses several landform regions or districts, the basic investigation is carried out separately for each; where blowouts, leaks or other events have had a major effect on the ecosystem, a detailed special investigation is to be carried out.

6.1.2 Investigation methods are chosen according to the content and include field survey, remote sensing survey, geophysical prospecting, drilling, enquiry and the collection of documents. The procedures and methods for surveying the present state of the geological environment follow GB 50021, GB/T 40112, HJ 25.1, DZ/T 0221, DZ/T 0287 and HJ/T 166; natural conditions, present land use and the present state of land damage and reclamation follow TD/T 1010, TD/T 1055-2019 and TD/T 1049; ecological conditions follow LY/T 1814, TD/T 1070.1 and TD/T 1070.7. Laboratory testing of organic pollutants, heavy metals and soil physical and chemical properties is carried out according to GB 15618, GB 36600 and HJ/T 166, and test reports issued by qualified testing bodies are to be provided.

6.2 On the basis of the results of the basic investigation, the present state of damage to the geological environment, of land damage and of ecological damage is analysed. The production and construction processes that may damage land are described and the type, range, area and degree of the land to be damaged are predicted for well fields, roads and pipelines according to TD/T 1031.5, stating the method and the basis of the prediction. Taking account of the susceptibility of the region to geological hazards, the analysis and prediction of damage to the geological environment and to the soil and water environment are outlined according to DZ/T 0223, with particular attention to the organic pollutants and the changes in the temperature field that extraction, storage and transport may cause, and with a brief analysis and prediction of damage to vegetation and to ecological functions. Finally, by comparison with a reference ecosystem, the ecological problems arising during exploration, development and construction, operation and decommissioning are diagnosed and their severity is graded according to TD/T 1070.1.

9 Project implementation

9.1 Protection, prevention and control and reclamation and restoration measures are to be proposed for the damage to the geological environment, to land and to the ecosystem throughout construction, production and reclamation. The reclamation and restoration standard is to match the original land use type or the same land use type in the surroundings, and new roads, irrigation and drainage and other supporting facilities are to connect with the surroundings. Reclamation follows the principle of reclaiming while extracting, temporary land being reclaimed as soon as construction ends, and new techniques, processes, equipment and materials are to be used. Because oil and gas land use consists of many points, long lines and wide areas, this document lays down the techniques and requirements for well fields, roads and pipelines: metering stations, central processing stations, transfer stations, gas gathering stations, booster stations and their ancillary facilities are point-shaped like well fields and are damaged mainly by occupation, so they follow the well field rules, while overhead power or oil transmission lines are line-shaped like pipelines and are damaged mainly by excavation, so they follow the pipeline rules. In plateau, hilly and mountainous areas geological safety hazards are to be removed and slope protection and construction follow GB 50330; before reclamation, abandoned oil or gas wells are sealed and the related facilities dismantled in accordance with SY/T 6646. In coastal zones the work is to be adapted to the local conditions of typical coastal ecosystems, coastal shelter forests, ecological sea dyke construction and coastal engineering improvement, on the basis of a detailed investigation and a suitability assessment. Buried pipelines involve two stages, temporary reclamation when construction ends and complete reclamation when the pipeline is no longer used. Measures are to be taken to prevent pollutants migrating and spreading outside the project area; where soil, surface water or groundwater is polluted, treatment follows HJ 25.4 and HJ 25.6, the disposal of the waste of mud pits and sewage pits and the filling of those pits follow HJ 607, and the treated soil, surface water and groundwater are to meet GB 15618, GB 36600, GB 3838 and the corresponding restoration and risk control targets.

9.2 The protection measures require that avoidance, mitigation and the protection of important species and cultural resources be defined at the design stage of resource development; that project sites avoid ecologically sensitive areas and comply with the management requirements of protected areas, scenic areas, world natural heritage, ecological conservation red lines and flood control red lines, and with territorial spatial planning and zoned ecological management; that the process design be optimised to reduce land damage, by controlling the land area of single wells, using cluster well drilling, horizontal and directional wells, shortening pipeline networks, strictly controlling the width of pipe trenches, laying pipes in shared trenches, controlling the length of new roads, using existing rural roads and strictly controlling the width and range of the working strip; that historic monuments, religious sites, protected historical and cultural areas, geological heritage reserves and scenic areas be avoided and, where that is impossible, protected in situ; and that, where protected or endemic plants and ancient and famous trees are adversely affected, the layout be optimised and the plants protected in situ or transplanted, all specimens in good condition and suitable for transplanting being transplanted, while for protected and endemic animals and their habitats the construction scheme and mode of operation are optimised and species rescue and habitat protection are carried out.

9.3 The prevention and control measures follow the principle of unified planning, control at source and the combination of prevention and treatment. Topsoil stripping and use: for well fields and new road construction land the topsoil is stripped and stockpiled in layers; in ecologically fragile areas such as deserts and tidal flats stripping may be omitted; in high altitude and cold areas turf is stripped, maintained and replaced. Stripped topsoil from well fields is stockpiled in strips on the nearby temporary land and that from new roads on the road temporary land, the method and technical requirements following TD/T 1048. The thickness stripped is determined from the properties of the topsoil and the volume of soil needed and is preferably not less than 30 cm, and may be increased in areas such as the north-east and the Huang-Huai-Hai plain where the soil layer is thick and fertile. Where pipelines are fully buried the trench may be excavated by machine or by hand, the topsoil along the route being stripped and stockpiled in layers to keep the physical and chemical properties of the layers stable and to reduce damage to the soil structure; palm mats or similar coverings may be laid in the stockpiling area to reduce surface disturbance, and the excavated topsoil and subsoil are stockpiled temporarily in layers on both sides of the working strip. After the pipeline work is finished backfilling is to be immediate, layered backfilling keeping the original soil profile and layer thickness as far as possible, and soil improvement measures may be carried out at the same time. Removal of stress factors: the site is chosen scientifically before construction so as to avoid areas where construction would trigger damage to the geological environment, and walls, retaining walls, revetments and drainage ditches are built around well fields, stations and roads, with regular patrol and monitoring of slopes; an early warning mechanism for damage to the soil and water environment is set up, temporary pollution control measures are laid down, the reuse rate of waste water is raised, pollution source isolation works prevent leachate from solid waste polluting surface water, groundwater and soil, plugging, water isolation and water stopping prevent cross-layer pollution of groundwater, and oil sludge, spilled oil and similar wastes are recovered and disposed of harmlessly in good time, temporary storage sites having anti-seepage foundations; high-risk sections of gathering and transmission pipelines are identified and assessed regularly, risk reduction measures are proposed and defects found by routine inspection are repaired.

9.4 The reclamation and restoration measures are set out for well fields, roads and pipelines. For well fields, temporary land no longer used is reclaimed in good time and construction land no longer to be retained should also be reclaimed; because the parcels are small, scattered and linear, land levelling, landscape planning and design, water system connection and other landform reshaping and landscape construction works are to be consistent with and in harmony with the surroundings. Reclamation is carried out, after masonry has been demolished and waste residue stripped, through soil reconstruction (clearing, soil covering, ploughing, levelling and biological and chemical measures), vegetation restoration and supporting works. Clearing of surface waste is carried out on the temporary land when well construction ends and on the construction land after the well has been closed and the masonry demolished and residue stripped; the clearing thickness is determined case by case and, after clearing, the gravel content of cultivated land and orchard land is to meet TD/T 1036. Where topsoil has been stripped, soil covering follows clearing, the thickness meeting TD/T 1036 and being increased as appropriate for mud pits and blow-off pits; where the direction is agricultural use the physical, chemical and nutrient properties are to meet the needs of cultivation and land reclaimed as arable land is to reach the quality grade required by GB/T 33469 for the same type of area. The topsoil stripped earlier is to be used as far as possible and backfilled in layers; where the soil source is insufficient soil may be brought from nearby, provided it causes no new ecological problem and meets TD/T 1036, and where none is available hole planting, lattice covering, strip covering, hydroseeding and similar new techniques may be used, or generated and residual soil improved by adding microbial agents and organic fertiliser; the harmful substance content of the covering topsoil is to meet GB 15618 and GB 36600. Ploughing after clearing loosens compacted soil, preferably to not less than 30 cm, and is not used in areas where the surface is desertified. Levelling follows the principle of harmony with the surrounding landscape and field size, cutting high ground and filling low ground by machine or by hand while avoiding mixing of topsoil and subsoil, terracing being used first in areas with steep slopes. Biological and chemical measures provide rapid fertility building where the land is reclaimed as arable or orchard land. Vegetation restoration follows the same land use type in the surroundings, forest land construction following GB/T 15776 and grassland construction NY/T 1342. The supporting works are roads, irrigation and drainage and farmland shelter works, built according to TD/T 1012, GB 50288 and GB/T 50817. For roads the same clearing, soil covering, ploughing, biological and chemical measures and vegetation restoration rules apply, levelling taking account of the design elevation of the earlier construction. For pipelines, soil reconstruction consists of levelling and biological and chemical measures together with vegetation restoration and supporting works, levelling being carried out at the same time as excavation and backfilling and the field slope being in harmony with the surroundings.

11 Monitoring, evaluation and adaptive management

11.1 Monitoring is to cover the whole process of construction, production and reclamation and restoration, with particular attention to ecologically sensitive areas and basic farmland. Taking account of the development and use plan and the extraction design, the objectives, tasks, objects, content, methods and requirements of the monitoring of damage to the geological environment, damage to land and damage to vegetation are to be described in detail. Monitoring of the effects of reclamation and restoration includes soil quality monitoring, which may be done by field survey and sampling and testing, and vegetation restoration monitoring, which may use field survey, sample plot measurement and visual estimation. On the basis of the monitoring results and by comparison with the reference ecosystem, the effectiveness of reclamation and restoration is assessed following GB/T 43935; the assessment is to cover ecological, social and economic benefits and, given that oil and gas projects have many scattered points, long lines, wide areas and small individual parcels, is to concentrate on soil, plant communities, the human settlement environment, public satisfaction and the increase in land value.

11.2 On the basis of monitoring and evaluation throughout, and against the reclamation and restoration objectives, the new ecological problems and potential ecological risks arising during the work are assessed; production processes and works that could lead away from those objectives or cause new damage are adjusted and corrected after approval through the prescribed procedure.