During the process of oil-based drilling, the adhesion of casing sealing grease and oil-based drilling fluid mixture to the casing wall of the production layer can easily cause frequent blockages during construction operations such as continuous tubing running down and pumping bridge plugs. Clear water cleaning, slippery water cleaning, and conventional surfactants have not effectively solved the problems on site. To address these issues, underground pipe cleaning technology has been developed.

Characteristics

Good cleaning: Efficiently clean the oil stains on the inner wall of the casing.

Appropriate viscosity: It can carry residual oil sludge out of the wellbore.

Effective solubilization: can enhance the dissolution effect of cleaning solution on oil stains.

Better lubrication: It has a good anti-wear and drag reducing effect between metal walls.

Advantages

Strong cleaning ability: This technology combines emulsion cleaning to enhance the dissolution and carrying of oil sludge in various ways, efficiently cleaning the oil stains inside the wellbore, ensuring the cleanliness of the wellbore wall, and facilitating the smooth progress of subsequent operations.

Good lubrication effect: This technology has strong lubrication effect while cleaning, especially when applied in horizontal wells, which can greatly reduce the friction between tools such as continuous tubing and downhole crawlers and the inner wall of the casing, providing a guarantee for the smooth progress of downhole operations.

Applications

Cleaning of oil-based downhole tubing: The downhole tubing cleaning technology, combined with emulsion cleaning, enhances the dissolution and carrying of oil sludge in various ways, efficiently cleans the oil stains in the wellbore, ensures the cleanliness of the wellbore wall, and facilitates the smooth progress of subsequent operations.

Wear resistance and drag reduction of metal wall: The downhole pipe cleaning technology has a strong lubricating effect, especially when applied in horizontal wells, which can greatly reduce the friction between tools such as continuous tubing and downhole crawlers and the inner wall of the casing, providing a guarantee for the smooth progress of downhole operations.

Case Studies

Fuling shale gas block

The downhole string cleaning technology has been applied in more than 200 wells in the Fuling shale gas block, with significant cleaning effects. It reduces the complexity of related operations for continuous tubing, greatly reduces operational risks, significantly improves operational failures, and reduces operational costs. The Fuling shale gas block has included downhole string cleaning fluid technology in drilling construction design, becoming a necessary process in the later stage of well completion.

Advantages and Effects:

High cleaning efficiency and good lubrication effect:This cleaning solution technology combines multiple functions such as emulsion cleaning, oil mud carrying, enhanced dissolution, lubrication, and drag reduction. It has shown excellent results in the cleaning of oil based mud downhole columns, ensuring smooth underground operations and reducing overall construction costs.