ENVIRONMENTAL PROTECTION OF OIL&GAS FIELDS

ABSTRACT Currently，shale gas site selection and determination in Southern Sichuan was affected by environmental sensitive and karst developing areas.In the meantime，basic farmland protection and land management policy have also made it hard for land expropriation.The contradiction between the current regional solid waste disposal capacity and the increasing amount for drilling cuttings has become increasingly prominent，following the pressure on drilling cuttings disposal is increasing.Furthermore，the difficulty in the processing of flowback fluids，the standard discharge is still facing the bottleneck of economic feasibility and emission standards et al，and non-technical risks exist with deep reinjection measures.In response to the above environmental protection constraints，the corresponding countermeasures were putting forward，respectively，according to the development distribution，land use safeguard，drilling cuttings and fracturing flowback fluids.

KEY WORDS Southern Sichuan；shale gas exploitation；environmental protection situation；countermeasures

ABSTRACT The produced water from ASP flooding was treated by settlement combined with filtration.However，polymers and viscosity could pose great impact on the removal of suspended solid and petroleum，which stress the treating mechanism of destabilization and decrease viscosity.In this study，the combination of air floatation settlement，biogenic oxidation，advanced oxidation，and second degree filtration technologies were applied for produced water from ASP flooding.After the treatment，the effluent water could stably reach the standard of reinject water，with petroleum lower than 800 mg／L，suspended solid lower than 350 mg／L，viscosity lower than 12 mPa·s，and PAM lower than 800 mg／L.It is easier to flush the filter and separate solid with fluid，the treating process stability could be increased，as well.This combination of treating technologies is of great importance for the reinjection of produced water to low permeability layers.

KEY WORDS ASP flooding produced water；destabilization；viscosity reduction

ABSTRACT Natural gas is transported by pipeline from production to external transportation.The environmental terrain along the pipeline is complex and some areas are densely populated，with potential safety hazards.The actuation state of the valve chamber is highly related to the effective control of the whole accident in case of pipeline breakage.Therefore，improving the safety control level of natural gas collection and transmission system linkage interlock can effectively improve the emergency security control ability.Based on the current operation status of well，station and pipeline operation control，the necessity of interlocking the valves along the pipeline，the upstream and downstream assembly stations and the production areas were analyzed.Combined with the characteristics of controllers scattered in each area of the assembly process，the system was optimized collectively，and the control protocols was optimized，too.As a result，linkage interlock was achieved for safety emergency control，and was effectively applied in practice，which significantly improved the level of natural gas safety collection and transmission.

KEY WORDS pipe control；interlock control；regional interlock protection

ABSTRACT The oxidation experiment of fracturing flowback fluid from a gas field in Sichuan after gel breaking and flocculation was conducted.Potassium permanganate，potassium persulfate，sodium hypochlorite，Fenton reagent were selected as oxidant.The results showed that：the optimum experimental condition for flocculation experiment could be reached with the additive of calcium oxide，aluminum sulfate，and ferrous sulfate of 3，1，1 g／L，respectively.The best experimental condition for oxidation experiment could be achieved with a dosing quantity of 0.5 g／L of potassium permanganate at p H 4；0.25 g／L of potassium persulfate at p H 6；15 g／L of sodium hypochlorite at p H 4；25g／L of hydrogen peroxide and 10 g／L of ferrous sulfate heptahydrate at p H 3.5.The effluent CODCr after the treatment could be reduced to about 800 mg／L，with the maximum CODCr removal rate of 72.96%，which could generate a plausible condition for the treatment afterwards.

KEY WORDS fracturing flowback fluid；pretreatment；oxidation；CODCr removal rate

ABSTRACT The mud soil after the treatment of waste drilling fluid was tested and analyzed according to the present situation of drilling waste in Dagang Oilfield，so as to treat drilling waste in accordance with the regulations and avoid and reduce its impact on the ecological environment.The concentrations of the pollutants were all within the scope of the second category of land use control values or screening values of GB 36600—2018“Soil Environmental Quality Construction Land Soil Pollution Risk Control Standards（Trial）”.The experiment data were compared by using the technology of non-burning brick，the ratio of raw materials and the harmlessness of the products were analyzed，as well.In addition，the seven major technological processes for the preparation of non-burning brick were introduced.The application of the non-burnt brick technology showed that，there is a better environmental effect by turning the mud soil into non-burnt bricks.

KEY WORDS Dagang Oilfield；drilling waste；bricks free；comprehensive utilization

ABSTRACT Aim for atmospheric environmental protection，the emission criteria of nitrogen oxides in the flue gas has been gradually decreased in recent years.In this study，the formation mechanism of NOX during combustion process was analyzed，followed by the improvement scheme to reduce NOX emission from heating furnace in refineries.After the reforming of the burner，low nitrogen combustion technology was applied to further reduce the NOX concentration below 100 mg／L，which meet the standard of“Emission Criteria of Pollutants in Petrochemical Industry”（GB 31570—2015）.

KEY WORDS Low-NOX Combustor；fuel-stag；flue gas recirculation

ABSTRACT The produced water during super heavy oil production in FengCheng Oilfield features a high density，high viscosity，high content of colloidal asphaltene.The large quantity of sediment and mud was hard to treat due to its relatively high emulsification stability.Furthermore，the oil content in the settling dehydration tank exceeded 10 000 mg／L，and the suspended matter exceeded 500 mg／L，posed significant impact on the water treatment system.A series technologies including gravity degreasing，dissolved air flotation，coagulation reaction，pressure filtration process was applied to treat the produced water from super heavy oil production.The oil content after treatment could reach less than 2 mg／L，and the sediment content of less than 2 mg／L.The effluent was reused for steam-injection boiler by 100%.As a result，this type of treatment could fully utilize the heat energy，and achieve recycle and reuse of the produced water.A total of effluent fee of 2 464.75×104 Yuan，natural gas usage of 5 475×104 Nm3 could be saved.

KEY WORDS produced water from super heavy oil production；treatment and reuse；steam injection boiler

ABSTRACT Leak Detection and Repair（LDAR）technology is used to discover and repair leakage of process equipment during industrial production activities.In this study，LDAR was applied to detect volatile organic compounds（VOCs）leaked from equipment components in Sulige Natural Gas Processing Plant.VOCs loss was calculated based on the statistical data on VOCs leakage，and the management system on leak detection and repair technology was established，as well.The long term efficient management on VOCs is achieved with environmental benefits.

KEY WORDS VOCs；LDAR；management system；photochemistry；Emission source

ABSTRACT In this study，general requirements for public participation in environmental impact assessment（EIA）of offshore oil and gas development projects were summarized based on a case study.According to the characteristics of EIA for offshore oil and gas development project，a series of problems existed in public participation，such as too wide range of public opinions，passive public participation，and weak legal awareness of a few individuals.In order to better provide scientific basis for decision-making departments，it is suggested that the public scope should be reasonably defined，the initiative and enthusiasm of public participation should be mobilized，and the public awareness of marine environmental protection should be raised.

KEY WORDS public participation；offshore oil and gas development project；environmental impact assessment

ABSTRACT The second pollution sources census of group corporation is an important measure to promote the green development of enterprises，an important basis for accurately judging the environmental protection state of enterprises，and effectively implementing environmental protection management.Currently，reported data for pollution sources census is of low quality，lack of consensus，and the pollution source archives were lacking management.Based on the above mentioned problems.a series of countermeasures were putting forward including strengthen publicity，deepen the understanding，enhance process control，and regulate the management of pollution source census archives.

KEY WORDS petroleum and petrochemical enterprises；pollution sources census；data；problem analysis；countermeasure

ABSTRACT In the HJ169—2018“Technical Guidelines for Environmental Risk Assessment on Projects”which took effect on Mar.1，2019，the preliminary judgment of risk potential was added，with an improved grading method of evaluation.Facing the above updated requirements，the oil and gas terminal equipped in offshore oil and gas development project were selected as an example.The environmental risk potential analysis was carried out，the hazardous materials were identified，and the risk level were classified for the materials and process systems.The environmental sensitivity was determined based on the analysis of atmosphere，underground water，and surface streams.As a result，the risk potential for the terminal project was determined.This study could provide practical guidance for environmental risk assessment of such projects.

KEY WORDS oil and gas terminals；environmental risks；risk potential

ABSTRACT In this paper，the composition of online monitoring system for petroleum pollution sources in China was introduced，and expounds the role of the system in capacity building of environmental supervision，improvement of the efficiency of environmental supervision and innovation during environmental protection management.Based on the application of pollution source online monitoring system in environmental protection management of CNPC，the main problems existing in the online monitoring，such as insufficient understanding，poor equipment selection，inadequate operation and maintenance management，etc.It is suggested that the importance of the online monitoring of pollution sources should be raised，the evaluation of online monitoring equipment and third-party operation and maintenance services should be carried out，and the application of online monitoring data of pollution sources should be deepened.

KEY WORDS CNPC；online monitoring of pollution sources；problems；suggestions

ABSTRACT Petrochemical enterprises urgently need to study the index system of environmental protection supervision，which can effectively guide enterprises to evaluate their environmental protection supervision ability.In this study，Through，the evaluation index system of environmental protection supervision in petrochemical enterprises was built based on literature review，on-site investigation，expert opinions and index screening.The key index were determined as supervision organization system，supervision system，supervision funds guarantee system and supervision evaluation system.The weight of each index is calculated by Analytic Hierarchy Process（AHP），which reflects the value status of each index in the system.This type of evaluation system could provide reference for petrochemical enterprises to build their own environmental protection supervision system.

KEY WORDS environmental protection supervision；petrochemical enterprises；index system；AHP

ABSTRACT Compared with other conventional peak shaving measures，gas storage has the advantages of large storage capacity，safety and reliability，and can reasonably adjust the unbalanced use of gas.Currently，gas storage has become the most important peak shaving method in China.Based on the characteristics of gas storage construction，this paper emphatically evaluates the impact of gas storage construction on ecosystem，soil and water conservation，vegetation and plant diversity，animals and their habitats，and puts forward environmental sensitive objectives and ecological restoration measures for key protection during construction and operation periods.This study could provide technical support for gas storage facilities that built in future to reduce the environmental impact from reservoir construction.

KEY WORDS gas storage；peak shaving；forest belt；ecology；environmental impact

ABSTRACT The shared problems within blowout prevention drill were summarized and analyzed，based on the thirty observation of emergency drills from the workover and operation teams in D oilfield in the past two years，and more than 80 emergency plans and records.In this study，a series of improvements for such emergency drills were proposed based on the point of view that“drill”is for“actual combat”，including preparation，contents，scenario simulation，and effect appraisal for emergency drills.

KEY WORDS well control；blowout prevention；environmental protection；emergency drill；problem；suggestion

ABSTRACT The construction of standardized team is an important catch to carry out the basic project of safety and environmental protection，deepen the construction of HSE management system，and strengthen the basic work of enterprises.In this paper，the main methods and experience from the construction of standardized stations in Liaohe Oilfield Company was introduced，including strengthening the basic construction effectively，promoting continuous improvement of the basic level safety and environmental protection work.A series of working protocols with features of Liaohe Oilfield were formed，which further consolidate the foundation of risk prevention and control.

KEY WORDS promotion；construction of standardized stations；risk prevention

ABSTRACT Most of the hidden dangers in oil and gas field production could be traced back to management reasons，which could further be attributed to the defects of the management cadres.Therefore，it is particularly important to improve the HSE capability of management cadres to ensure the safe development of oil and gas fields.In this paper，an effective practical training mechanism and method for HSE management cadres was raised，which could effectively cultivate HSE management and supervision talents，enhance the＂four abilities＂of core HSE management cadres，and enhance the overall quality of grassroots backbone HSE management and supervision team.

KEY WORDS oil and gas fields；HSE management；cadre；practical training

Vol.29 No.3 2019 Tot.No.130