Segmented Wellbore Plugs for Multi-Zone Fracturing
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Solution Overview
Problem
In well treatments, especially for long horizontal wellbores, maintaining sufficient flow velocity and pressure to effectively fracture and treat multiple zones is challenging due to fluid bleeding and proppant settling, which can lead to incomplete treatment and blockage of lower zones.
Innovation Solution
The use of a drillable plug or packer assembly that divides the well into segments, allowing for controlled fracturing and treatment of each zone by blocking perforations with a diverter and increasing pressure to open central flow passages, ensuring each zone receives adequate treatment fluid and pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If treatment fluid is flowed through multiple zones simultaneously, then all zones receive treatment, but flow velocity decreases and proppant settles out
Solution Approach 1:
The wellbore is divided into multiple isolated zones using settable plugs or packers positioned between zones. Each zone is treated sequentially by isolating it from other zones, allowing high flow velocity to be maintained in the active treatment zone without fluid bleeding into other zones. This segmentation enables complete proppant transport and effective fracturing in each zone.
2Stress or pressure
If treatment fluid is pumped at high pressure to fracture zones, then fracturing is achieved, but pressure loss occurs and lower zones cannot be properly treated
Solution Approach 1:
Zones are isolated using settable plugs that create separate pressure zones. High pressure can be applied to each isolated zone without pressure bleeding into other zones, ensuring sufficient fracturing pressure is achieved in each zone while minimizing overall pressure loss.
Solution Approach 2:
Settable plugs are positioned in the wellbore before treatment to pre-establish zone isolation. This preliminary action prevents pressure loss during treatment by ensuring zones are sealed off beforehand, allowing maximum pressure to be applied where needed.
3Ease of operation
If diverter is used to block perforations, then fluid direction is controlled, but additional equipment and complexity are required
Solution Approach 1:
The diverter function is combined with the settable plug or packer assembly. The same device that isolates zones also provides perforation blocking capability, eliminating the need for separate diverter equipment and reducing overall system complexity while maintaining effective fluid direction control.
Data Source
AI summary
A method of treating each of multiple formation zones in a subterranean well can include isolating two of the zones from each other in the wellbore with a plug assembly positioned in the wellbore; treating one of the zones by flowing a treatment fluid through openings that provide fluid communication between the wellbore and one of the zones; then blocking flow through the openings; increasing pressure in the wellbore in response to the blocking; and opening the plug assembly in response to the pressure increasing. A well treatment system for treating each of multiple zones intersected by a wellbore can include multiple plug assemblies in the wellbore, each of the plug assemblies isolating a respective adjacent pair of the zones from each other in the wellbore. Each of the plug assemblies opens in response to a respective predetermined pressure differential applied across the plug assembly.