Wired Drill Pipe Depth Correction via Repeater Inversion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Accurate determination of the depth of an earth formation penetrated by a drill bit is challenging due to drill pipe elongation and distortion caused by tension, temperature, and other environmental factors in wired drill pipe telemetry systems.
Innovation Solution
The implementation of repeaters with measurement devices along the drill string that acquire 'along string measurements' and use an inversion procedure to correct for pipe elongation, incorporating sensors for axial loading and environmental effects, allowing for precise calculation of true formation depth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If drill pipe length is measured at surface under atmospheric conditions, then depth reference is established for measurements, but pipe elongation due to tension and environmental factors causes measurement inaccuracy
Solution Approach 1:
The patent applies preliminary action by measuring the drill pipe length at the surface under atmospheric conditions before deployment, establishing a baseline reference length. This preliminary measurement is then used in conjunction with inversion procedures to correct for elongation that occurs during actual drilling operations, allowing accurate formation depth determination despite the pipe lengthening under tension and environmental stress.
Solution Approach 2:
The patent implements feedback through an inversion procedure that uses measurements from repeaters along the drill string to continuously correct for pipe elongation. The system measures the actual position of repeaters at different depths, compares these measurements with expected positions based on surface-measured pipe length, and uses this feedback to calculate correction factors that compensate for tension-induced elongation and environmental effects, thereby maintaining measurement precision.
2Reliability
If repeaters are placed at predetermined intervals along the drill pipe, then signal boosting is achieved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the drill string into multiple sections with repeaters placed at predetermined intervals. Each repeater acts as an independent signal boosting station, segmenting the overall signal transmission path. This segmentation allows the signal to be refreshed and amplified at regular intervals, maintaining reliable communication over the entire length of the drill string without requiring a single complex long-range transmission system.
Solution Approach 2:
The repeaters serve as intermediary devices between the surface control system and the bottom hole assembly. Each repeater receives, amplifies, and retransmits signals, acting as a mediator that extends the effective communication range. This intermediary approach allows reliable signal transmission through the drill string by breaking down the long transmission path into shorter segments, each handled by an intermediate repeater station.
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
This method provides accurate and corrected formation depth measurements by accounting for pipe elongation and environmental factors, enhancing the precision of wellbore depth logging and formation characterization.
Implementation Method 1
When the drill pipe is in the well and suspended by a rig, the drill pipe is under tension due to the weight of the pipe. This creates an elongation of the drill pipe as compared to its length measured at the surface.
Implementation Method 2
Other environmental factors may increase or decrease the length of the pipe. These factors include temperature, internal verses external fluid pressures, accumulated turns due to torque, and amount of sliding and rotating friction forces acting on the pipe.
Data Source
AI summary
A method includes accepting as input to a processor measurements of a characteristic of a subsurface formation made at a plurality of spaced apart positions along a pipe string moved along a wellbore. Measurements are made of pipe string depth in the wellbore from the Earth's surface. The measurements of pipe string depth include measurements of apparent depth of each of the spaced apart locations. The subsurface formation is identified from the measurements of the characteristic. A true depth of the subsurface formation is made using the measurements of pipe string depth and apparent depth of the formation from each of the spaced apart positions. A record of measurements of the characteristic with respect to depth corrected for changes in length of the pipe string caused by axial forces along the pipe string is generated.