Dual-Pathway Wellbore Assembly for Lost Circulation Control
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Solution Overview
Problem
Lost circulation occurs when drilling fluid flows into fractures in geological formations during drilling operations, leading to mud waste, dry drilling, and downhole problems, which can result in time and resource losses.
Innovation Solution
A wellbore assembly that includes a drill string and a housing, where the drill string defines two fluid pathways, one through the drill bit and another through the housing. The assembly flows two different lost circulation materials (LCMs) through these pathways to a lost circulation zone, with the larger particles of the second LCM forming a base plug and the smaller particles of the first LCM accumulating to further seal the zone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If drilling fluid is pumped at high pressure to maintain circulation, then circulation efficiency is improved, but fluid loss into formation fractures increases
Solution Approach 1:
Lost circulation materials (LCMs) act as intermediary substances that bridge the gap between the drilling fluid and formation fractures. These materials are carried by the drilling fluid to the fracture zones where they accumulate to form plugs, preventing direct fluid loss into the formation while maintaining circulation pressure and efficiency
Solution Approach 2:
The invention changes the physical parameters of the drilling fluid system by introducing LCMs with varying particle sizes, densities, and shapes. These parameter changes allow the fluid to deposit materials at specific fracture zones, transforming the fluid's behavior from purely circulating to also plugging and sealing, thereby reducing fluid loss without sacrificing circulation efficiency
2Loss of substance
If lost circulation materials are introduced to plug fractures, then fluid loss is reduced, but drilling operation complexity increases
Solution Approach 1:
The LCM system is segmented into multiple classes based on particle size, density, and shape characteristics. Different LCM classes are introduced sequentially or simultaneously through the drilling fluid to target different fracture types and sizes, creating a systematic approach that manages complexity through organized categorization rather than random material addition
Solution Approach 2:
The drilling fluid serves multiple functions: it acts as both the circulating medium for drilling operations and the transport vehicle for LCMs. This multi-functionality reduces overall system complexity by combining what would otherwise be separate systems into a single integrated fluid that performs both circulation and plugging functions
3Reliability
If multiple classes of lost circulation materials are used to effectively seal fractures, then sealing effectiveness is improved, but material cost increases
Solution Approach 1:
Different LCM classes with specific properties (particle size, density, shape) are targeted to specific fracture characteristics and locations within the formation. This local quality matching ensures that each LCM class is used where it is most effective, optimizing sealing performance while minimizing the total quantity of materials required compared to using a single universal LCM type throughout
Data Source
AI summary
A wellbore assembly that includes a drill string and a housing. The drill string defines a first fluid pathway extending from the drill string, through the drill bit, and out the drill bit to flow a first lost circulation material. The housing stores a second lost circulation material including at least one parameter different from the first lost circulation material. The drill string defines a second fluid pathway extending from the drill string, through the housing, and out the housing to direct, with the first fluid pathway blocked, fluid along the second fluid pathway to flow the second lost circulation material out the housing to a lost circulation zone of the wellbore. The drill string directs, with the second fluid pathway blocked, fluid along the first fluid pathway to flow the first lost circulation material out the drill bit to the lost circulation zone to plug the lost circulation zone.