How can you minimize formation damage and remediation during well abandonment?

Understanding what mud weight or fluid weight to use when testing for feed rates can help you stop breaking down formations. Good fluid management in your well planning helps you ensure your isolating techniques work whether it is cement or any of the other technologies. Understanding your reservoir is a key to good isolation. There is also tools to expand the casing to help allow for annular barriers if formations break down to easily even with good fluid management.

Understanding reservoir charateristic is key for a successful and effective abandonment. From these information, one could design a cement to be used, fluid weight, etc. The challenge is that we might deal with reservoir that is too porous or vugular, where fluid loss are common and successful cementing become very difficult to achieve. In this case, knowing the other formation's characteristic above our target reservoir will be important. We'd try to find the impermeable formations (i.e.. low permeability, shale) to increase the chance of isolating the target reservoir.

First, employ proper drilling and completion practices to avoid damage during initial operations. Select optimal drilling fluids and additives to mitigate formation impairment. During abandonment, use non-damaging fluids to displace wellbore fluids, preventing fines migration. Implement zonal isolation techniques, like cementing, to seal off productive zones securely. Additionally, employ perforation techniques that minimize skin damage. Regularly monitor well conditions and consider advanced technologies such as expandable liners for enhanced zonal isolation. Finally, adhere to regulatory guidelines and industry best practices to ensure a comprehensive and effective well abandonment process.

Minimizing formation damage during well abandonment is essential for environmental protection and reducing future liabilities. Use a strategic approach, employing practices such as cleaning the wellbore, placing cement plugs, and employing selective perforation. Opt for environmentally friendly fluids and avoid overflushing. Consider resin consolidation for stabilization and conduct operations at low pressures. Set packers effectively, monitor post-abandonment, and perform risk assessments. Adhere to regulatory standards and responsible decommissioning practices. By integrating these measures, well abandonment can be conducted with minimal formation damage, ensuring sustainable closure and environmental stewardship.

Understanding what mud weight or fluid weight to use when testing for feed rates can help you stop breaking down formations. Good fluid management in your well planning helps you ensure your isolating techniques work whether it is cement or any of the other technologies. Understanding your reservoir is a key to good isolation. There is also tools to expand the casing to help allow for annular barriers if formations break down to easily even with good fluid management.

Competent production casing and primary cement must be in place to ensure no loss of cement or fluids to uphole zones during the abandonment. The casing should be pressure tested against the bridge plug or retainer being prior commencing cementing operations. A cement bond log prior to abandonment may be performed; if poor zonal isolation behind casing is detected, remedial perf and squeeze may be performed prior to filling the casing with cement. Competent production casing, cement behind casing with good zonal isolation on the CBL, a full cement plug in casing with all perfs squeezed, and a robust cut and cap procedure, will ensure the well is fully isolated and permanently abandoned.

You do need to perform pressure tests to confirm plug integrity of permanent mechanical barriers. Efforts to clean the casing from hydrocarbons contribute to the initial and most importantly the long term permanent isolation of the formation. Cutting corners at this point can be a costly mistake.

Plugs placement will be depend on well condition (open hole, cased hole, subsea well), the length and reservoir location in the well and points towards the use of tools such as bridge plugs, retainers, baskets or cement as a barrier. Por example: Zones in Open Hole: cement plug (s) set from at least 100 feet below the bottom to 100 feet above the top of oil, gas and fresh water zones to isolate fluids

First off abandonment to leave for good and isolate that part or the entire well. My choice would be to set a bridge plus in between the plugs and get a positive test. That to me is one of the proper ways to preform an abandonment . Now there’s casings to be cut if required.

Any deficiency in primary cementation tends to affect insulation in the long term; Additionally, large fluctuations in pressure and temperature within the wellbore can negatively affect the integrity of the cement or cause loss of adhesion. Tectonic stresses can also fracture set cement. Whatever the cause, loss of cement integrity can result in fluid migration, deterioration of formation insulation, or casing collapse, even when high-quality cement is placed that initially provides a good seal.

Formation damage during abandonment might most likely occur if a cement squeeze is being performed against a formation in an open hole. The formation damage can be minimized by skilfully killing the well if a potential permeable zone is present. Placing an open hole cement support tool to support the base of the cement plug and then as per NORSOK standard mentioned below performing the abandonment plugs. NORSOK D-010, Rev 4: “Abandonment of open hole with cement plugs. The last open hole section of a wellbore is abandoned permanently by setting an open hole cement plug across/above the reservoir and with an additional cement plug from the open hole into the casing.”

For an abandonment to be successful, the isolation of the hydrocarbon-bearing intervals, overpressured intervals, uncemented anular, and any freshwater intervals penetrated by the wellbore is critical to successful abandonment. The abandonment plan must be based on the types of fluids contained in reservoirs and the well's mechanical condition at the time of abandonment. Government regulations and guidelines for abandonment, should be considered as well environmental safety aspects

Although I believe that formation damage shouldn’t be a key target for permanent abandonment. However, compatibility of mud and formation is a key point to plan for stability issues that might be a risk while P&A. Formation fluids, characteristics and cutting samples should be sent to the labs with the mud suggested to have positive planned results and tweak the mud to the formation.

Thorough reservoir analysis, careful zone selection, use of compatible fluids, controlled pressure, and effective wellbore cleanup are key to minimizing formation damage during well abandonment.

To minimize formation damage and remediation during well abandonment, consider these practices: 1. **Proper Well Cleaning** 2. **Fluid selection** 3. **Injection Techniques** 4. **Isolation Techniques** 5. **Monitoring and Analysis** 6. **Qualified Personnel** 7. **Regulatory Compliance** 8. **Post-Abandonment Monitoring** By integrating these practices, drilling engineers can minimize formation damage and remediation challenges during well abandonment, promoting a more environmentally responsible and efficient process.