Operation risks and safety precautions of the hott

Operation risks and safety precautions of oil and gas long-distance pipelines

introduction

the pipeline facilities that transmit the crude oil and natural gas collected and processed in oil and gas mines to users are called oil and gas long-distance pipelines. In oil field gathering and transportation production, pipelines with a diameter greater than 150mm and an oil and gas transmission distance greater than 100km are generally called oil and gas long-distance pipelines

I. pipeline risk analysis

1 Third party damage

includes human factor damage and natural disaster damage. Such as illegal construction above the pipeline, drilling holes in the pipeline to steal oil, soil movement near the pipeline, landslides, etc., may lead to the failure of the pipeline

2. Corrosion

includes external corrosion, internal corrosion and stress corrosion. Soil, failure of cathodic protection and aging of insulation coating will lead to external corrosion of the pipeline; Improper construction and installation will cause stress corrosion

3. Operation

includes construction misoperation and operation misoperation. Before the pipeline is put into operation, carry out on-the-job training for construction workers to avoid causing pipeline pressure holding and valve damage; In the process of operation, the Chinese herbal medicine strictly implements the dispatching instructions and the operating procedures to avoid the condensation and shutdown of the pipeline due to the failure of the oil pump and heating furnace, the oil delivery volume of the pipeline cannot reach the design flow or the temperature drop along the pipeline is too large

4. Material defects

include initial defects of pipes and construction defects. The initial defects are generated in the process of manufacturing, construction and transportation; Installation defects are formed during the construction of the pipe section. The existence of these defects leads to the reduction of pipeline strength. It directly affects the reliability of pipeline operation

II. Safety precautions

1 The technical data of pipe design, installation and acceptance are complete

the paint color, color ring, flow direction indication and other signs of oil and natural gas pipelines should be obvious, eye-catching and comply with relevant regulations. There must be a pipe layout plan in the data, with complete marks and accurate location; The management system of oil and natural gas pipelines is sound (such as the regular patrol inspection system), and special personnel are designated to implement it, conduct regular inspection, and have complete records

2. The pipeline has no serious corrosion leakage, and the anti-static accumulation measures are reliable

the oil and natural gas pipeline should meet the process design parameters and have no leakage (3 points/1000m). The underground or semi underground pipeline should meet the requirements of relevant regulations. The pressure bearing pipeline must have sufficient strength, and no point corrosion with a depth of more than 2mm and surface corrosion with a depth of more than 200mm2 are allowed. The thermal insulation layer of the thermal pipeline shall be intact, and the thermal compensation device shall meet the relevant requirements. The external anti-corrosion insulation layer and cathodic protection device of the pipeline are in good condition

3. The pipeline safety protection meets the requirements to ensure that the crude oil, stable light hydrocarbon and saturated vapor pressure at 20 ℃ buried in the nearby facilities are less than 0 1MPa natural gas condensate, pressure less than or equal to 0 The distance between 6Mpa oilfield gas pipeline and residential areas, villages and towns, public welfare facilities, industrial and mining enterprises, etc. shall not be less than 10m

the support, hanger and other components of the pipeline should be firm and reasonable. When the overhead laying pipe is under the traffic channel, there should be corresponding span height and eye-catching warning signs; The laying depth of buried pipelines meets the standard requirements, and the coating is complete without damage

4. The pipeline crossing meets the specification requirements to prevent mutual influence

the location of the crossing water area and gully conforms to the general trend of the line. When the pipeline crosses the water area and gully embankment foundation, and the ground on both banks is lower than the river level, a water stop ring or water blocking wall shall be set. When crossing railways and highways, avoid stone areas, high fill areas, cutting, and steep slope sections with the same slope direction on both sides of the road. Pipelines on the ground should avoid crossing roads, railways and navigation channels as far as possible. When the intersection cannot be avoided, the crossing height at the intersection should also enable pedestrians, vehicles and ships to pass safely. Underground pipelines are generally laid along roads, and appropriate distances are maintained between various pipelines for installation and maintenance; The surface of the heat supply pipeline has an insulating layer, which is laid in the trench or protective pipe. It should avoid being crushed by soil and make the pipe expand and move

5. Strengthen pipeline insulation and anti freezing measures to reduce the risk of external forces

for steam pipelines, high-temperature pipelines, low-temperature pipelines and pipelines with anti scalding and anti freezing requirements, thermal insulation materials need to be wrapped outside the pipelines to prevent the loss of heat (cold) in the pipelines or freezing. For some liquid pipelines with high freezing point, heating and insulation are also required to prevent the liquid from being too sticky or solidifying and affecting the transmission. Common insulation materials include cement perlite, glass wool, rock wool and asbestos diatomite. When there are many kinds of pipelines, in order to facilitate operation and maintenance, paint the surface of the pipeline with the specified color for identification

for example, red is used for steam pipes, light blue is used for compressed air pipes, etc

6. Take various anti-corrosion cleaning methods to prolong the service life of pipelines

in order to prevent the soil erosion of the soil leading group office located in the Ministry of industry and information technology, the surface of underground metal pipelines should be coated with anti-corrosive paint or tar, asphalt and other anti-corrosion coatings, or coated with glass cloth and linen impregnated with asphalt. Cathodic protection devices shall be set for pipelines buried in highly corrosive low resistance soil to prevent corrosion. In order to prevent atmospheric corrosion, steel pipelines on the ground are usually coated with various anti rust paints. All kinds of pipes should be cleaned before use, and the interior of some pipes should also be cleaned regularly. In order to facilitate cleaning, some inevitable problems in resin production and molding processing are solved by setting filters or purging holes on the pipes. On long-distance oil and natural gas pipelines, it is necessary to regularly remove the dirt accumulated in the pipelines with sweepers. Therefore, special devices for sending and receiving sweepers should be set up

7. Strengthen pipeline leakage detection means and reduce shutdown reaction time

in order to ensure the safe operation of the pipeline and stop the expansion of the accident in time when an accident occurs, in addition to installing detection and control instruments and safety valves on the pipeline, special safety measures are also taken for some important pipelines, such as installing accident relief valves or emergency block valves on coal gas pipelines and long-distance oil and natural gas pipelines. They can automatically and timely stop transportation in case of disastrous accidents, so as to reduce disaster losses

8. Establish the "three prevention and four responsibilities" protection system, strengthen the monitoring of oil and gas leakage

increase its strength and wear resistance through the establishment of combined station transportation and appropriate heat treatment process Sometimes, special steel is inlaid at the jaw, or steel sand is sprayed on the jaw surface Oil pump automatic continuous remote monitoring, early warning alarm and station control pump shutdown defense line; Monitoring of intermediate block valve of pipeline in sensitive area and remote emergency block line; C919, a sensitive water source and river, is the first "three lines of defense" developed in accordance with the latest international airworthiness standards for the construction of oil intercepting infrastructure such as trunk civil aircraft and remote monitoring defense lines, as well as the "four" levels of oil and gas leakage prevention and control system of Oilfield companies, plants (offices), operation areas (brigades) and basic production units, thus forming a comprehensive oil and gas leakage prevention and control system from patrol to management, and then to regions and key parts, The goal of "timely discovery, rapid disposal and effective control" has been achieved

conclusion

due to the importance of oil and gas long-distance pipelines in the national economy, as well as the great harm and environmental damage caused by oil and gas leakage, when strengthening safety precautions, we should also increase daily safety management, regularly drill emergency plans, regularly inspect and repair pipelines, and have complete inspection and maintenance records; There is an emergency plan for pipeline accidents, rescue personnel and equipment are in place, and emergency rescue drills for pipeline accidents are carried out regularly