Lost Circulation Shapes for Sealing Large Subterranean Cavities
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional lost circulation materials are ineffective in sealing cavities with widths larger than 4-6 millimeters in subterranean wells, leading to excessive fluid loss and operational challenges such as well control issues and formation damage.
Innovation Solution
An optimized combination of lost circulation shapes and materials is deployed in a specific sequence, determined by geophysical data, to effectively seal larger cavities by using hollow perforated geometric shapes that trap the material and accumulate it within the formation, preventing fluid loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional lost circulation materials are used, then sealing of small cavities (4-6 mm) is effective, but sealing of larger cavities (>6 mm) is ineffective
Solution Approach 1:
The lost circulation material is divided into multiple size fractions (e.g., 4-6 mm, 6-10 mm, 10-25 mm). Smaller particles seal smaller cavities first, while larger particles are retained by the progressively smaller mesh screens of previously deployed materials, enabling effective sealing across a wide range of cavity sizes up to 25 mm
Solution Approach 2:
Larger lost circulation material particles are nested within the structure formed by smaller particles. The smaller materials act as retaining screens that hold back larger particles, creating a nested configuration where each size fraction is contained by the previous smaller fraction, enabling progressive sealing of cavities from small to large dimensions
2Adaptability or versatility
If larger lost circulation material is used to seal bigger cavities, then cavity size coverage increases, but material retention becomes difficult
Solution Approach 1:
The material is segmented into discrete size fractions that are deployed in sequence. Each fraction serves a specific retention function: smaller fractions retain even smaller particles, while larger fractions are retained by the mesh structure of smaller fractions already in place, ensuring reliable retention across all size ranges
Solution Approach 2:
Different size fractions are placed in different spatial locations and deployment sequences. Smaller materials are deployed first to create retention structures, followed by larger materials that are locally retained by these smaller structures, optimizing both cavity size coverage and material retention at each location
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
The method allows for effective sealing of cavities with cross-sectional dimensions up to 25 mm, reducing fluid loss and maintaining well stability, thereby preventing formation damage and operational issues.
Implementation Method 1
The lost circulation shape is a hollow perforated geometric shape that can fill with wetting fluid and have a generally neutral buoyancy in the drilling fluid
Implementation Method 2
The lost circulation shape can act as a trap for the conventional lost circulation material and allow for accumulation and bridging of the lost circulation material onto the lost circulation shape
Data Source
Figure 1~2
Figure 3~5
Figure 6~7
AI summary
Methods and systems for sealing a lost circulation zone associated with a subterranean include determining geophysical data of the lost circulation zone. An available range of lost circulation shape data and an available range of lost circulation material data is provided. The geophysical data, the available range of lost circulation shape data, and the available range of lost circulation material data are part of a fixed data set. An initial lost circulation mix is determined from the fixed data set. An initial drill string downhole flow rate and an initial annulus uphole flow rate are determined and an initial loss volume is calculated. The initial lost circulation mix is delivered into the subterranean well. A revised drill string downhole flow rate and a revised annulus uphole flow rate are determined and a revised loss volume is calculated.