Reduced Drag Casing Coupling for Horizontal Wellbore Advancement
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Solution Overview
Problem
Conventional casing couplings with square leading edges face challenges in extended lateral wells, as they push debris and increase friction, requiring higher forces to advance the casing string due to hang-ups on wellbore irregularities, making it difficult and inefficient to achieve the target casing setting depth.
Innovation Solution
The development of casing couplings with an integral Reduced Drag feature, featuring a lead-in chamfer and optional bullet nose configuration, which reduces drag and provides wear protection, allowing the coupling to ride over wellbore irregularities instead of collecting debris, thus reducing the torque needed for advancement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional square leading edge couplings are used, then coupling strength and structural integrity are maintained, but drag and friction increase significantly when advancing through horizontal wellbores
Solution Approach 1:
The coupling leading edge is modified from a square geometry to a curved or rounded geometry. This curvature allows the coupling to ride over wellbore irregularities and debris more easily, reducing the plowing effect and drag force experienced during advancement through horizontal wellbores, while the overall coupling strength is maintained through proper structural design.
2Productivity
If square leading edge couplings are used, then manufacturing simplicity is maintained, but debris accumulation and hang-ups increase during casing advancement
Solution Approach 1:
The curved leading edge geometry prevents debris from accumulating at sharp corners and edges. The smooth curvature allows debris to be pushed aside more effectively and reduces the tendency for material to pack up against the coupling, thereby reducing hang-ups and improving the overall advancement rate through horizontal sections.
3Power
If square leading edge couplings are used, then structural simplicity is maintained, but torque requirements increase to overcome friction and wellbore irregularities
Solution Approach 1:
The curved leading edge reduces the torque required to advance the casing string by minimizing friction and the plowing effect. The rounded geometry allows the coupling to more easily ride over wellbore irregularities and reduces resistance, thereby lowering the power requirements for casing installation despite the increased geometric complexity.
Data Source
AI summary
A modified API Buttress threaded casing connection for use in oil and gas wells incorporates an integral Reduced Drag (RD) feature that comprises a tapered or rounded leading edge. In certain embodiments, both ends of the coupling incorporate the integral Reduced Drag (RD) feature that comprises a tapered or rounded leading edge to facilitate removal of the casing from a wellbore.