CIRCULAR

Regulations on the preservation and abandonment of oil and gas wells

 

 

Pursuant to the Oil Law dated July 6, 1993; the Law Amending and Supplementing Certain Provisions of the Oil Law No. 19/2000/QH10 dated June 9, 2000; the Law Amending and Supplementing Certain Provisions of the Oil Law No. 10/2008/QH12 dated June 3, 2008;

Pursuant to Decree No. 98/2017/NĐ-CP dated August 18, 2017, of the Government stipulating the functions, tasks, powers, and organizational structure of the Ministry of Industry and Trade;

Pursuant to Decree No. 95/2015/NĐ-CP dated October 16, 2015 of the Government detailing certain provisions of the Oil Law;

Pursuant to Decree No. 33/2013/NĐ-CP dated April 22, 2013 promulgating the Model Contract for the Sharing of Petroleum Products;

Pursuant to Decision No. 04/2015/QĐ-TTg dated January 20, 2015 of the Prime Minister stipulating management of safety in petroleum activities;

Pursuant to Decision No. 49/2017/QĐ-TTg dated December 21, 2017 of the Prime Minister regarding the clearance of facilities, equipment, and means serving petroleum activities;

At the proposal of the Director of the Department of Oil and Gas and Coal;

The Minister of Industry and Trade issues this Circular prescribing regulations on the preservation and abandonment of oil and gas wells.

PART I

GENERAL PROVISIONS

Article 1. Scope of application

This Circular prescribes the conduct of activities for the preservation and abandonment of oil and gas wells with the purpose of protecting natural resources, the environment, and the natural structure of the earth's crust, preventing actions that lead to the creation of obstacles or disturbances to the state of the marine environment as well as on land.

Article 2. Applicability

This Circular applies to:

1. Operators, Joint Ventures for Oil and Gas and organizations and individuals (hereinafter collectively referred to as Operators) implementing activities for the preservation and abandonment of wells during the course of exploration, development, and exploitation of oil and gas within the territory of mainland, islands, archipelagos, internal waters, territorial seas, contiguous zones, exclusive economic zones, and continental shelves under the sovereignty, sovereign rights, and jurisdiction of Vietnam, as determined by Vietnamese law and international treaties to which Vietnam is a party.

2. Organizations and individuals related to the activities of preserving and abandoning oil and gas wells.

 Article 3. Definitions

In this Circular, the following terms shall be understood as follows:

1. Well preservation is the use of appropriate fluids, reinforcing plugs, and installing equipment in the well to ensure that the well remains safe for a certain period of time and can subsequently facilitate further exploration, testing, and production activities.

2. Drilling program is a document prepared by the Operator including contents related to plans, technical solutions, progress, and preliminary well completion plans to implement the construction of one or more wells in a field or block.

3. Cement retention tool is a device used during high-pressure cement injection to prevent cement flow up or down in the well. A cement retention tool is a non-retrievable sealing device made of metal or other suitable material that can be drilled through.

4. Well abandonment is the recovery of wellbore equipment, reinforcing cement plugs, setting mechanical plugs, cutting off and recovering sections of tubing in the well, and clearing obstructions around the wellhead if present.

5. Preliminary well completion plan is a document detailing the planned abandonment or preservation of a well or part of a well prepared by the Operator in the drilling program.

6. Well completion is the work of abandoning or preserving a well or part of a well.

7. Well completion plan is a document prepared by the Operator before implementing well completion.

8. Perforation interval is any section of the well that has been cased and perforated to create communication between the casing and the wellbore or between different casing strings.

9. Cement plug is a quantity of cement slurry injected into the wellbore to a certain depth to form a solid cement barrier separating different reservoir intervals along the wellbore. The position of the cement plug includes depth and length determined vertically along the wellbore.

10. Mechanical plug is a device used to isolate the wellbore made of metal and rubber that can be drilled through, commonly used to isolate different intervals in a cased wellbore.

Chapter II

WELL COMPLETION PLAN

Article 4. Submission of the well completion plan

1. When implementing well completion, the Operator must submit the well completion plan at least five working days in advance for the Vietnam Oil and Gas Group to review and approve two working days in advance.

2. For the completion of wells included in the plan for the clearance of facilities, equipment, and means serving petroleum activities, based on the plan for the clearance of facilities, equipment, and means serving petroleum activities approved by the Ministry of Industry and Trade according to Decision No. 49/2017/QĐ-TTg dated December 21, 2017 of the Prime Minister, the Operator must submit the well completion plan to the Vietnam Oil and Gas Group in accordance with Clause 1 of this Article.

3. During the implementation of the well completion plan, the Operator must coordinate with the Vietnam Oil and Gas Group and relevant ministries, sectors, and localities to notify the well completion plan as prescribed.

4. In the drilling program for the entire field, block, or each individual well, the Operator must prepare a preliminary well completion plan after drilling completion for wells not yet put into production.

Article 5. Contents of the Well Abandonment Plan

The Well Abandonment Plan must include the following contents:

1. Reasons for well abandonment.

2. Basic data on the well, a summary of the drilling and completion process; basic data on the exploitation and utilization process of the well, geological and geophysical data of the well, results of cement bond quality tests outside the production casing and between casings, formation pressure, fracture pressure at the bottom of the casing shoe, and related documents to the well or well sections that need to be abandoned or preserved.

3. A schematic diagram of the well structure indicating: well depth, depth of casing columns, height of cement columns in annular spaces; type and density of fluids in the well and in annular spaces; types of equipment installed in the wellbore. For directional deviated wells and horizontal wells, the inclination depth, vertical depth, well section depth, inclination angle, and azimuth angle must be clearly stated.

4. Methods for setting mechanical plugs and cement plugs including the plug setting procedure, plug material type, cement slurry volume, fluid displacement volume, placement interval and depth, pressure and load testing methods with specific test values. For wells that need to be abandoned, the method and cutting depth of the casing must be specified.

5. Plans for cleaning up and surveying around the wellhead area before and after well abandonment, moving or dismantling the rig.

6. Timing and duration for conducting well abandonment, periodic inspection plans for preserved wells.

7. Emergency response plans for oil spills at sea, chemical leaks at sea, and marine environmental protection activities in accordance with laws on environmental protection and marine resources and islands.

Article 6. Well Abandonment Report

1. The Operator shall submit a report on the well abandonment process to Vietnam Oil and Gas Group within thirty days after completing the work.

2. For wells where well abandonment is immediately carried out after completing the drilling program, the Operator may prepare the well abandonment report as part of the well drilling completion report.

3. All documents related to the well abandonment work, including the actual condition diagrams of the well after abandonment and documents obtained from the final survey regarding surface conditions and surrounding areas of the well, must be attached to the well abandonment report.

4. For wells included in the plan to clean up facilities, equipment, and means serving oil and gas operations, the Operator must comply with Decision No. 49/2017/QĐ-TTg dated December 21, 2017 of the Government Prime Minister.

5. The Operator shall be responsible for safety, environment, and consequences arising from well abandonment.

6. The Operator shall notify and update information about preserved and abandoned wells to Vietnam Oil and Gas Group.

Chapter III

WELL PRESERVATION WORK

Article 7. General Requirements for Well Preservation

1. The wellbore must remain in a safe condition even if wellhead equipment is damaged due to incidents or removed, ensuring isolation between formations and between formations and the surface, except when formations are being exploited simultaneously.

2. Ensuring the ability to reuse the well for drilling, research, exploitation, repair, or other forms, or abandoning the well at any time while maintaining safety.

3. Minimizing interference of equipment with the surrounding environment.

4. Buoy markers must be installed for preserved subsea wells located in waters less than twenty meters deep.

Article 8. Classification of Wells Requiring Preservation

Based on the well condition, wells requiring preservation are divided into three categories:

Category 1: Long-term preserved wells (three years or more), including wells whose research results show potential for economic exploitation but lack a usage plan.

Category 2: Temporary preserved wells (one to three years), comprising wells included in the exploitation plan but classified as backups.

Category 3: Short-term maintained wells (less than one year), including operational wells temporarily halted for repairs or preparation for use.

Article 9. Well Casing Preservation

1. The process of installing equipment or reinforcing plugs for well maintenance must ensure pressure control below the plugs before they are removed during the reopening of the well.

2. During the preservation period, for type 1 drilled wells, the wellhead extraction equipment must be removed from the wellhead and cement plugs or mechanical plugs must be placed to isolate the open strata intervals. The method of placing plugs shall be similar to that prescribed in Chapter IV of this Circular.

3. Type 2 wells may retain the production string in the well in its operational state. During the maintenance period, the well must remain full of well maintenance fluid.

4. Type 3 wells may maintain the entire well in its original state, but valves must be closed and all valve handles removed, except for wells using subsea wellheads.

Article 10. Well Preservation Fluids

The operator must ensure that when a portion or the entire well requiring preservation is of type 1 or type 2, the well must always be filled with fluid of sufficient density to control the formation pressure existing in the drilled well before conducting well preservation operations. Preservation fluids must be treated to prevent corrosion of equipment.

Article 11. Preservation of Subsea Wellheads

1. For wells with subsea wellheads located offshore, the orientation cable system must be cut and retrieved before moving the drilling rig from its position.

2. The inner part of the wellhead of preserved or completed wells must be treated against corrosion, and the outer part of the wellhead must be protected from damage due to impact and equipped with means to easily identify the wellhead location.

3. In areas where the sea level depth is less than 20 meters, to avoid danger to subsea wellheads and guide pipes as well as passing vessels, the operator must install marker buoys to signal the presence of preserved subsea wells.

Article Article 12. Preservation of Surface Wellheads

1. Drilled wells on fixed platforms that require preservation must have a Christmas tree installed at the wellhead. All valves except the check valve must be removed. Branch pipelines and pressure relief gauges must be removed, and blind flanges or plugs must be installed on the ends of the pipelines and pressure gauge bases. A sign measuring 0.4 m x 0.2 m must be affixed to the wellhead, indicating the name of the oil field, the well, the name of the responsible operator, the start date of preservation, the reason for preservation, and the preservation duration.

2. Drilled wells on land that require preservation must be similarly preserved as those specified in Clause 1 of this Article, and additionally, these wells must be protected by a reinforced concrete fence measuring 4 m (length) x 4 m (width) x 2 m (height). A sign measuring 0.4 m x 0.2 m must be affixed to the fence, indicating the name of the oil field, the well, the name of the responsible operator, the start date of preservation, the reason for preservation, and the preservation duration.

Article 13. Inspection of Preserved Wells

1. The operator is responsible for inspecting preserved wells using appropriate methods and equipment according to international oil industry practices to detect abnormalities in the well area. If abnormalities are detected in the well area, the operator must take measures to ensure safety.

2. The responsible operator must conduct periodic inspections of preserved wells as follows:

a) Annually for type 1 wells requiring preservation;

b) Quarterly for type 2 wells requiring preservation;

c) Monthly for type 3 wells requiring preservation.

3. For wells with subsea wellheads that require preservation, the first inspection for type 1 and type 2 wells must be conducted one year after the preservation date. Based on risk assessment, the operator may propose subsequent inspections every two years from the first inspection date. If abnormalities are detected, the operator must take corrective measures and report to PetroVietnam and the Ministry of Industry and Trade.

4. Inspection results must be reflected in the corresponding operational reports of the operator.

Article Article 14. Preservation Duration

The operator is responsible for bringing type 1 preserved wells back into operation or abandoning them within the permitted preservation period but not exceeding six years from the preservation date. This preservation period may be extended if the operator demonstrates that the extension meets safety and environmental protection requirements under Vietnamese law and international oil industry practices.

Chapter IV

WELL ABANDONMENT WORKS

Article Article 15. General Requirements for Well Abandonment

1. Wells to be abandoned must ensure the integrity of the wellbore, preventing the flow of fluids between formations and the seafloor or surface.

2. After completing well abandonment work, the seabed or surface area around the drilling site must be cleaned up, without leaving any obstructions or disrupting the natural environment's initial state.

Article Article 16. Cutting and Retrieval of Casing, Wellheads, and Wellbore Equipment

1. The operator may not retrieve casing left in the well unless approved in writing by PetroVietnam.

2. The operator must apply mechanical or hydraulic methods to cut and retrieve the wellhead. Casing must be cut close to the natural seabed surface, and the wellhead system must be retrieved, ensuring no part protrudes above the seabed surface, causing hindrance to maritime activities or other offshore operations.

3. For onshore wells, the depth of cutting the wellhead and tubing must be at least 3 meters below ground level.

4. When cutting casing, the operator must pay attention to the following points:

a) If the overlapping sections of two casing columns were not grouted with cement, the inner casing column can be cut and retrieved. The depth of the cut is based on the height of the cement plug in the annular space, determined through well logging data;

b) If there is a possibility of excess pressure remaining in the outer annular space, it must be thoroughly addressed before proceeding with the casing cut, using supplementary reinforcement techniques as stipulated in Article 20 of this Circular;

c) Before cutting the tubing, the density of the wellbore fluid must be adjusted appropriately to match the formation strength at the bottom of the tubing.

5. All wellbore equipment must be retrieved. In cases where technical retrieval is not feasible, consistent with environmental protection regulations and ensuring safety during the execution of oil contracts, the operator must include a plan in the well completion program for PetroVietnam's review and approval. Leaving behind wellbore equipment must comply with Clause 1 of Article 15, Article 22, and Article 23 of this Circular.

6. Leaving behind the wellhead or a portion of the casing must be carried out in accordance with Article 23 of Decision No. 49/2017/QĐ-TTg dated December 21, 2017, issued by the Prime Minister.

Article 17. Positions of Cement Plugs in Open-Hole Sections

1. Oil and gas reservoirs, abnormally pressured zones, or zones causing loss of cement slurry in open-hole sections must be isolated by cement plugs placed over the entire zone plus at least 50 meters above the top and 50 meters below the bottom of the zone (Annex - Figure 1).

2. If the open-hole section has a length of less than or equal to 250 meters and a diameter smaller than 215.9 mm (8.5 inches), a cement plug must be placed from the bottom of the well up to at least 50 meters above the deepest casing shoe (Annex - Figure 2).

3. If the open-hole section exceeds 250 meters (>250 meters) and the zones within this section do not contain oil and gas or have no abnormal pressure, only one cement plug with a minimum length of 100 meters covering 50 meters above and 50 meters below the deepest casing shoe must be placed (Annex - Figure 3).

4. If the open-hole section has abnormal pressure or contains oil and gas zones where the drill string, tools, casing, and other equipment are stuck, these devices must be retrieved to release the open-hole section to the maximum extent possible and then plug and abandon the open-hole section in accordance with Clause 1 of Article 18 of this Circular.

5. If the open-hole section causes loss of circulation of cement slurry making it impossible to place the cement plugs as specified in Clauses 1, 2, and 3 of this Article, the Operator must place a mechanical plug on the deepest casing shoe within a range of 50 meters and a cement plug with a minimum length of 100 meters immediately above the mechanical plug (Annex - Figure 3a).

Article 18. Positions of Cement Plugs in Cased-Well Sections

1. To ensure isolation between the cased-well section and the open-hole section, the Operator must place a balanced cement plug with a minimum length of 100 meters covering 50 meters above and 50 meters below the deepest casing shoe (Annex - Figure 4).

2. In cases where wellbore conditions do not allow effective isolation using a balanced cement plug, the Operator may implement one of the following methods:

a) Mechanical Plug Method: Place a mechanical plug on the deepest casing shoe within a range of 50 meters and a cement plug with a minimum length of 100 meters immediately above the mechanical plug (Annex - Figure 5);

b) Cement Retainer Tool Method: The deepest casing shoe can be isolated by placing a cement retainer tool 50 meters away from the casing shoe, followed by pumping cement through this tool. The volume of cement slurry must ensure a cement plug of 100 meters in length below the cement retainer tool, followed by placing a cement plug with a minimum height of 15 meters above the cement retainer tool (Annex - Figure 6);

c) If a cement plug is used to isolate the overlapping portion of the surface casing with the previous casing shoe, this cement plug must have a minimum length of 100 meters and be placed ≥ 50 meters above and ≥ 50 meters below the hanging point of the surface casing (Annex - Figure 7);

d) In cases where casing is run through salt or flowing sand formations (flowing zones), to prevent casing distortion due to flowing zones, the cement plug must be placed through the entire thickness of the flowing zone to withstand external pressures. If the flowing zone is thicker than 200 meters, at least two cement plugs must be placed, one through the bottom boundary and one through the top boundary of the flowing zone (Annex - Figure 8).

Article 19. Abandoning Drilled Sections that Have Been Fractured

If a well has been hydraulically fractured, the fractured intervals must be isolated sequentially using mechanical plugs, cement plugs, or both mechanical and cement plugs if permitted by distance. The process of abandoning the well section must be carried out according to one of the following methods:

1. Cement Plug Replacement Method: Place a cement plug across the fracture interval and extend it from 15 m to 30 m above and from 15 m to 30 m below the fracture interval or extend it to the nearest mechanical plug (Annex - Figure 9).

2. Mechanical Plug Method: The fractured intervals can be isolated by placing a mechanical plug (or a production packer with a plug) within 15 m to 30 m from the top of the fracture interval, and a cement plug at least 15 m long must be placed above this mechanical plug (Annex - Figure 10).

3. Cement Slurry Injection Method: To isolate abnormal pressure zones and prevent fluid flow between zones and behind casing, the fracture intervals must be injected with cement slurry. The injection process must be conducted by pumping cement through a cement retainer tool placed at least 15 m above the fracture interval (Annex - Figure 11a) or a combination tool with backpressure (Annex - Figure 11b). At the same time, at least 25 m of cement must remain above any retained injection tools left in the well.

Article 20. Additional Strengthening Measures

1. Casing Perforation and Cement Injection: To prevent fluid circulation between the zone and annular spaces, there must be at least 100 m of good adhesion cement inside the bottom of the casing before the next casing. If not, the innermost casing must be perforated at a depth of 100 m above the bottom of the preceding casing, and an equivalent volume of cement slurry of 100 m annular space must be injected through the perforated section using a cement retainer tool or packer with a pressure not exceeding the formation fracturing pressure (Annex - Figure 12).

2. Casing Perforation and Circulation: If the cement injection method cannot be performed due to the safe pressure limit of the casing, the inner casing immediately below the bottom of the preceding casing must be perforated further, and cement must be injected up to at least 100 m of the annular space within the newly perforated section (Annex - Figure 13).

3. The perforation points described in paragraphs 1 and 2 of this Article shall be plugged with cement as specified for the fracture intervals under Article 19 of this Circular.

Article Article 21. Plugging in Case of Casing Cutting

1. When cutting casing for recovery as provided in paragraphs 2 and 3 of Article 16 of this Circular, the ends of the cut casing strings must be isolated using one of the following methods:

a) Cement Plug Replacement Method: A balanced cement plug of length ≥ 100 m will be used to isolate the end of the pulled casing extending ≥ 50 m below and ≥ 50 m above the cut casing end (Annex - Figure 14);

b) Cement Slurry Injection Method: Place a cement retainer tool in the larger casing string at 50 m above the cut casing end and inject cement slurry through the retainer tool. The cement slurry volume must ensure filling ≥ 100 m of the casing below the retainer tool (50 m inside and above the cut casing end) and 15 m above the retainer tool (Annex - Figure 15).

2. Before cutting and recovering surface casing and directional casing, a mechanical plug must be placed in the surface casing at a depth of 200 m below the seabed for offshore wells or below the rotor table for onshore wells. A surface cement plug of length ≥ 100 m must be placed above this mechanical plug.

3. For onshore wells, the ends of the cut surface casing and directional casing must be filled with cement, and the wellbore foundation must be leveled to return to its original natural state, and at the well location, a steel sign measuring 0.4 m x 0.2 m must be installed indicating the name of the mine, the well name, the Operator's name, and the date, month, and year of well abandonment.

Article 22. Placing a Plug in Case of Leaving Wellbore Equipment

In cases where the Operator is permitted to leave wellbore equipment according to Clause 5, Article 16 of this Circular, the placement of the plug must be carried out in accordance with the following regulations:

1. If the Operator can prove that there exists a packer and cement collar outside the production casing above the strata to be isolated, of good quality, then it may proceed to cut and recover the equipment above the production packer, followed by placing a cement plug with a minimum length of 100 meters at the depth level of the packer (Annex - Figure 16a).

2. Where the cement ring outside the production casing does not meet quality requirements, drilling and injecting cement into the annular space must be performed, followed by carrying out as specified in Clause 1 of this Article (Annex - Figure 16b).

Article 23. Requirements for Testing the Plug

1. Checking position and load testing of cement plugs:

a) A waiting period of at least six hours must be observed for the cement plug to set, after which the tool string must be lowered to determine the position of the cement plug and a load of at least ten tons must be applied to test the accuracy of the placement and the setting quality of the cement plug;

b) If the cement plug is placed off its intended position or cannot withstand the test load, another cement plug must be placed as a replacement, followed by re-determining the position and testing the load of the newly placed cement plug according to the method described in point a, Clause 1 of this Article.

2. Requirements for pressure testing of plugs:

a) To confirm the isolation status of the open hole section below the deepest casing shoe, the cement plugs and mechanical plugs mentioned in Clause 2 and 3 of Article 17 of this Circular must be pressure tested to a value higher than the acceptance pressure of the formation at the casing shoe 3,450 kPa (500 psi) within fifteen minutes;

b) The cement plugs and mechanical plugs mentioned in Article 18 of this Circular must be pressure tested to a value higher than the acceptance pressure of the formation at the casing shoe 3,450 kPa (500 psi) within fifteen minutes;

c) The cement plugs and mechanical plugs mentioned in Articles 19 and 20 of this Circular must be pressure tested to a value higher than the formation pressure of the tested interval 3,450 kPa (500 psi) within fifteen minutes;

d) The cement plugs mentioned in Clause 1 of Article 21 of this Circular must be pressure tested to a value higher than the acceptance pressure at the next casing shoe 3,450 kPa (500 psi) within fifteen minutes.

3. For wells using subsea wellheads, in addition to complying with the provisions of Clauses 1 and 2 of this Article, the Operator must conduct tests on the ability of fluid intrusion into the wellbore for the cement plugs and mechanical plugs as stipulated in Article 19 of this Circular to ensure no fluid intrusion from the formation into the wellbore.

4. Conditions for the plugs to meet the requirements for pressure testing within fifteen minutes without a reduction in test pressure exceeding ten percent.

 

Article 24. Fluids Used in Well Abandonment Operations

1. When part or all of a well is abandoned, the well must be filled with fluid of sufficient density to control the existing pressure in the formation before commencing well abandonment operations.

2. The fluids in the drilled well must be treated to prevent corrosion of the casing.

3. For open hole sections of the well before cement plug placement, a high viscosity spacer fluid must be placed to prevent cement from settling to the bottom of the drilled well.

Article 25. Cement for Well Abandonment

1. The cement used to place any cement plug in the drilled well must have a compressive strength of at least 3,000 kPa (435 psi) after setting for eight hours.

2. For high temperature and high pressure wells, the cement used to place any cement plug in the well must have a compressive strength of at least 3,500 kPa (508 psi) after setting for a period of forty-eight hours.

Article 26. Seabed Survey During Well Abandonment

1. The Operator must ensure that after abandoning a well, the seabed area around the wellhead must be carefully surveyed to ensure that all obstructions have been thoroughly removed.

2. The final seabed survey reports must be submitted along with the well completion report as required by Article 6 of this Circular.

Chapter V

IMPLEMENTING PROVISIONS

Article 27. Special Cases

When applying the method of cutting the wellhead and casing with specialized explosives; new technical solutions; new materials for preserving and abandoning wells; extending the preservation period of wells, the Operator must provide documentation proving the plan, technical solutions, risk assessment, and meeting safety and environmental protection requirements under Vietnamese law and international oil and gas industry practices for relevant Vietnamese authorities to consider approval in accordance with Decision No. 04/2015/QĐ-TTg dated January 20, 2015 and Decision No. 49/2017/QĐ-TTg dated December 21, 2017 of the Government.

Article 28. Transitional Provisions

In cases where well preservation and abandonment work has been approved and implemented before this Circular takes effect, the Operator, agencies, organizations, and individuals shall continue to implement according to the Well Preservation and Abandonment Regulations issued together with Decision No. 37/2005/QĐ-BCN dated November 25, 2005 of the Minister of Industry.

Article 29. Effectiveness and Implementation

1. This Circular takes effect from September 10, 2020, and Decision No. 37/2005/QĐ-BCN dated November 25, 2005 of the Minister of Industry issuing the Well Preservation and Abandonment Regulations shall be repealed from the date this Circular takes effect.

2. During the implementation of well preservation and abandonment, if there are difficulties or obstacles, the Operator and Vietnam Oil and Gas Group shall report to the Ministry of Industry and Trade for consideration and resolution within their authority./.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ANNEX

Diagram describing well completion operations

(Attached to Circular No. 17/2020/TT-BCT dated July 17, 2020 of the Minister of Industry and Trade on well preservation and abandonment)

 

1. Positions of plugs in open hole sections

 

 

 

                                                                                                                  

 

 

 

 

 

 

 

 

 

2. Positions of plugs in cased hole sections                                          

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         

 

 

 

 

 

 

 

 

 

 

 

 

 

 

                                                                            

 

 

 

 

 

 

 

 

3. Abandoning drilled sections that have been perforated

 

                                                                                     

 

 

 

 

 

 

 

 

                                                                                                                                                                  

 

 

 

 

 

                                                                                                                            

 

 

         4. Additional reinforcement measures