Downhole Tool Placement Using Micro Dogleg Severity
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Solution Overview
Problem
Traditional dogleg severity methods are insufficiently exact, making it difficult to determine proper placement of downhole tools in wells with micro doglegs, which can impair tool passage.
Innovation Solution
A method and apparatus that utilize micro dogleg severity (MDLS) to determine tool placement by obtaining survey data, calculating dogleg angles for short intervals, converting to MDLS in degrees per set length, and generating tables or graphs to identify maximum tool dimensions suitable for wellbore curvature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional dogleg severity methods are used, then the measurement process is simple, but the placement precision of downhole tools is insufficient
Solution Approach 1:
The wellbore survey data is divided into small measured depth intervals (less than 8 meters), and dogleg angles are calculated for each interval separately. This segmentation allows detection of micro doglegs that would be missed by traditional methods using larger intervals, thereby improving placement precision without requiring entirely new measurement equipment.
Solution Approach 2:
The patent introduces a new dimension of measurement by converting dogleg angles into micro dogleg severity (MDLS) values expressed in degrees per set length, where set length is a standardized measurement unit. This dimensional transformation enables precise characterization of wellbore curvature at the micro-scale, allowing accurate determination of tool placement zones.
2Measurement precision
If micro dogleg severity is calculated for short intervals, then tool placement accuracy improves, but the amount of data processing increases
Solution Approach 1:
The patent pre-establishes standardized set length values and pre-provides lookup tables or graphs that map MDLS values to maximum allowable tool dimensions. This preliminary preparation allows rapid determination of suitable tool placements without performing complex real-time calculations, reducing data processing time while maintaining high precision.
Solution Approach 2:
Instead of performing complex real-time geometric calculations during tool placement, the patent creates lookup tables or graphs that copy and pre-compute the relationship between MDLS values and maximum tool dimensions. This allows operators to quickly query suitable tool sizes for any given depth interval without reperforming the complex calculations, significantly reducing processing time.
3Reliability
If the wellbore has micro doglegs, then tool passage becomes more difficult, but traditional methods cannot detect these curvatures
Solution Approach 1:
The survey data is segmented into short measured depth intervals (less than 8 meters), which enables detection of micro doglegs that would be averaged out or missed by traditional methods using longer intervals. This segmentation approach increases the sensitivity of the measurement system to small curvatures in the wellbore.
Solution Approach 2:
The patent changes the measurement parameter from traditional dogleg severity (over longer intervals) to micro dogleg severity (MDLS) calculated over short intervals. This parameter transformation makes the measurement system sensitive enough to detect and quantify micro doglegs, providing reliable information for tool placement decisions in curved wellbores.
Data Source
AI summary
Data from a well survey includes information on wellbore depth in combination with inclination and azimuth or bending moment taken at measured depth intervals with sufficient short spans to detect micro doglegs in a wellbore over lengths less than, for example, thirty meters. A conversion quantifies micro dogleg severity detected for expression in units of degrees per standardized set length. The converted quantification may also be used in circle-based equations to determine maximum tool length or width for passing tools through the wellbore due to the micro doglegs. Disposing the tool in the wellbore may occur at a location identified to accommodate the tool.