Dual-String Wellbore Drilling and Cementing Apparatus

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Solution Overview

Problem

Existing wellbore drilling and cementing methods require multiple trips and do not effectively utilize sensors due to oversized hole openings, which affect sensor accuracy and do not provide means for reaming remaining pilot holes.

Innovation Solution

A drill string apparatus with an inner string equipped with a drill bit, sensors, and reamers, and an outer string with reamers, allowing for drilling, enlarging, and cementing in a single trip by attaching at multiple landing locations to manage hole sizes and sensor placement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a reamer is used to enlarge the pilot hole to the final size, then the hole is opened to the required dimensions for the outer string, but the distance between the sensor and the borehole wall increases, reducing measurement precision

Engineering Contradiction:

Improveborehole sizeVSAvoidsensor measurement accuracy

Core Design Contradiction:

Manufacturing precisionVSMeasurement precision

Solution Approach 1:

The reaming operation is divided into two separate stages: first, the inner string with its reamer enlarges the pilot hole to an intermediate size; second, the outer string with its reamer enlarges the hole to the final size. This segmentation allows the sensor to remain close to the borehole wall during the critical measurement phase while still achieving the required final dimensions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The inner string performs preliminary drilling and initial reaming of the pilot hole before the outer string is deployed. This preliminary action creates a prepared borehole that can be further enlarged by the outer string's reamer, allowing the sensor to take measurements at the optimal intermediate stage before final enlargement increases the sensor-to-wall distance.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If multiple trips are made to drill, ream, and cement the wellbore, then each operation can be performed with optimal equipment configuration, but the total time and number of operations increase

Engineering Contradiction:

Improveoperation qualityVSAvoidtotal drilling time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent combines drilling, reaming, and cementing operations into a single integrated trip by deploying both the inner string and outer string simultaneously. The inner string performs drilling and initial reaming while the outer string performs final reaming, and both strings remain in place for the subsequent cementing operation, eliminating the need for multiple trips to the surface.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The dual-string system is designed to perform multiple functions: the inner string with drill bit and reamer, the outer string with reamer, and both strings serving as conduits for cementing. This multi-functional design allows a single trip to accomplish what traditionally required separate operations, reducing overall time while maintaining operation quality.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentEP2888431B1Apparatus and method for drillng a wellbore, setting a liner and cementing the wellbore during a single trip

Publication Date: 2021.03.10 BAKER HUGHES CO

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AI summary

A method of forming a wellbore is provided that in one embodiment includes conveying an inner string and an outer string downhole; attaching the inner string to the outer string at a first location and forming the wellbore; and attaching the inner string to the outer string at a second location uphole of the first location and cementing an annulus between the outer string and the wellbore, without retrieving the inner string from the wellbore.