Logging Tool Integrated in Drillstring for Deviated Wellbore
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Solution Overview
Problem
Conventional logging methods, such as wireline logging, face challenges in highly deviated or horizontal wellbores and unstable formations, where gravity is insufficient to lower logging tools to total depth, and immediate casing installation is necessary to prevent wellbore instability, making these methods difficult, time-consuming, and expensive.
Innovation Solution
The method involves drilling a wellbore using a drillstring with a cutting tool and injecting drilling fluid, deploying a Bottomhole Assembly (BHA) with a logging tool through the drillstring, forming a bore in the cutting tool, and inserting the logging tool to log the formation while tripping the drillstring in or out of the wellbore, allowing for logging during drilling or shortly after.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If wireline logging is used in highly deviated or horizontal wellbores, then logging data can be obtained, but the operation becomes difficult and time-consuming due to insufficient gravity to lower logging tools
Solution Approach 1:
The patent replaces the conventional wireline mechanical lowering system with a drillstring-based deployment system. The logging tool is integrated into the drillstring and deployed using drilling fluid circulation and pressure differential mechanisms, eliminating the need for gravity-dependent wireline lowering in deviated wellbores.
Solution Approach 2:
The drillstring serves multiple functions: it performs drilling operations and simultaneously serves as a deployment conduit for the logging tool. This multi-functionality allows the same equipment to accomplish both drilling and logging tasks without requiring separate specialized equipment for deviated wellbores.
2Reliability
If wireline logging is used in unstable formations requiring immediate casing installation, then formation stability is protected, but logging operations become difficult and risky
Solution Approach 1:
The logging operation is performed during the drilling process itself, before casing installation is required. This preliminary action allows formation evaluation to be completed while the wellbore is still open, eliminating the need to wait for casing installation and reducing operational risks in unstable formations.
Solution Approach 2:
The patent combines the drilling operation and logging operation into a single integrated process. The logging tool is deployed through the drillstring during active drilling, merging two previously separate operations into one simultaneous process, thereby eliminating the need for separate logging runs in unstable formations.
3Loss of information
If multiple logging runs are performed to access different wellbore sections, then comprehensive formation data is obtained, but logging time and costs increase
Solution Approach 1:
The patent merges multiple logging operations into a single continuous run by integrating the logging tool into the drillstring. As the drillstring is tripped in and out of the wellbore, the logging tool continuously records formation data across all accessible intervals, eliminating the need for multiple separate logging runs and significantly improving productivity.
Data Source
Figure 1
Figure 1A~1B
Figure 1C
AI summary
Embodiments of the present invention generally relate to methods and systems for logging through a drillstring. In one embodiment, a method of logging an exposed formation includes drilling a wellbore by rotating a cutting tool disposed on an end of a drillstring and injecting drilling fluid through the drillstring; deploying a BHA through the drillstring, the BHA including a logging tool; forming a bore through the cutting tool; inserting the logging tool through the bore; longitudinally connecting the BHA to the drillstring; and logging the exposed formation using the logging tool while tripping the drillstring into or from the wellbore.