Wash Pipe Seal System for Fluid Loss Control in Well Completions
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Solution Overview
Problem
The challenge in completing open hole oil, gas, and water wells lies in controlling fluid losses during the removal of the wash pipe, as aggressive filter cake breakers can cause substantial fluid loss into the formation, impairing well productivity and requiring costly remedial steps.
Innovation Solution
A method and apparatus that utilize a one-way bypass valve and seal system to isolate the annulus during wash pipe withdrawal, allowing aggressive filter cake breakers to be used without excessive fluid loss, by recirculating fluids and maintaining pressure balance through a fluid loss control device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If aggressive filter cake breakers are used to quickly remove filter cake, then filter cake removal effectiveness is improved, but fluid loss to the formation increases
Solution Approach 1:
The wellbore is divided into isolated zones using packers and seals. The treatment zone is segmented from the annulus, allowing aggressive breaker to be applied locally without causing widespread fluid loss. The seal on the wash pipe creates a segmented isolation that prevents fluid communication between zones during withdrawal.
Solution Approach 2:
A seal or packer is introduced as an intermediary element between the wash pipe and the formation. This intermediary creates a barrier that allows the aggressive breaker to work on the filter cake while preventing the resulting fluid loss from affecting the overall wellbore fluid balance.
2Speed
If aggressive filter cake breakers are used, then filter cake removal speed is improved, but formation damage increases
Solution Approach 1:
The treatment area is segmented from the rest of the formation using packers and seals. This allows high-speed aggressive breaker application localized to the filter cake zone without exposing the entire formation to the harmful effects of rapid fluid loss and chemical treatment.
Solution Approach 2:
The aggressive breaker's harmful effect (rapid fluid loss) is converted into a benefit by containing it within an isolated zone. The controlled fluid loss in the sealed-off treatment zone effectively removes the filter cake without damaging the broader formation, as the lost fluid is replaced or contained.
3Loss of time
If wash pipe is withdrawn quickly, then installation time is reduced, but fluid loss control becomes difficult
Solution Approach 1:
Packers and seals are installed in advance to create isolated zones before the wash pipe is withdrawn. This preliminary action ensures that when the wash pipe is quickly removed, the fluid loss is already contained within predefined zones, maintaining reliability even during rapid operations.
Solution Approach 2:
The system transitions from a static sealed configuration during treatment to a dynamic state during wash pipe withdrawal. The seal moves with the wash pipe, maintaining dynamic isolation that allows quick withdrawal while preserving fluid loss control throughout the process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the use of aggressive filter cake breakers to quickly and effectively remove filter cake, reducing fluid losses and improving production by allowing the wash pipe to be withdrawn without substantial fluid loss, thereby preventing formation damage and reducing well control issues.
Implementation Method 1
a one-way bypass valve associated with the seal. As the wash pipe is withdrawn, fluid is passed down the wash pipe to replace the volume previously occupied by the pipe. If more fluid than necessary is pumped, the one-way valve provides a route for this fluid to return to the surface
Implementation Method 2
A method and apparatus that utilize a one-way bypass valve and seal system to isolate the annulus during wash pipe withdrawal, allowing aggressive filter cake breakers to be used without excessive fluid loss
Implementation Method 3
The filter cake breaker is a chemical designed to remove the filter cake material placed across the formation during the drilling process
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a method and apparatus for avoiding fluid loss during installation of a lower completion in an open hole oil, gas or water well. A lower completion assembly (3, 33) comprising tubing with production perforations, for example in a sand screen, is run into the well on drill pipe (8, 38). The lower completion (3, 33) is hung from a packer (4, 34), together with a wash pipe (9, 39) which extends through the inner of the lower completion (3, 33). At the proximal end of the lower completion is a seal (15, 45) through which the wash pipe (9, 39) extends. An aggressive breaker fluid is circulated through the wash pipe, through a float shoe (11, 41) at the end of the completion. Once circulation is completed, the aggressive breaker removes all filter cake from the formation in 30 minutes. The wash pipe (9) is withdrawn but, because the wash pipe (9) seals against the seal (14) as it is withdrawn, fluid is not lost into the formation via the lower completion. The wash pipe (9) is made from flush jointed tubing which allows the seal to be uninterrupted as the wash pipe is withdrawn.