Real-Time Rock Strength Prediction for Horizontal Well Placement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge in drilling subterranean formations is the difficulty in predicting rock strength variation, which affects drilling speed and the ability to geo-steer the wellbore into favorable reservoir layers due to the heterogeneity of formations and the delay in rock strength measurements from Logging-While-Drilling (LWD) tools.
Innovation Solution
Predicting confined compressive strength (CCS) and unconfined compressive strength (UCS) using downhole drilling parameters, such as mechanical and hydraulic specific energy, to monitor and control the wellbore placement in real-time, enabling efficient geosteering into lower rock strength regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Logging-While-Drilling (LWD) tools are used to measure rock strength, then rock strength can be evaluated while drilling, but the measurement is delayed and available hours after the formation is drilled
Solution Approach 1:
The patent calculates rock strength parameters (UCS and CCS) in real-time using drilling parameters measured at the bit location, performing the evaluation action preliminarily and immediately rather than waiting for delayed LWD measurements. This allows geosteering decisions to be made based on current formation conditions rather than historical data.
2Productivity
If rock strength is not known before drilling, then drilling can proceed without prediction, but it is difficult to diagnose low ROP and determine actions to improve ROP
Solution Approach 1:
The patent implements a feedback mechanism where rock strength parameters (UCS and CCS) are continuously calculated from real-time drilling parameters and fed back to the drilling operation. This enables immediate diagnosis of low ROP conditions and allows operators to adjust drilling parameters or wellbore trajectory based on current formation strength characteristics.
3Productivity
If the wellbore is placed in higher rock strength regions, then drilling may be more challenging, but rock strength prediction is needed to avoid this issue
Solution Approach 1:
The patent enables dynamic wellbore placement adjustments by calculating real-time rock strength parameters (UCS and CCS) that reflect current formation conditions. Operators can dynamically modify the wellbore trajectory to target zones with favorable rock strength characteristics, optimizing the balance between drilling efficiency and wellbore placement flexibility throughout the drilling process.
Data Source
AI summary
A system for predicting rock strength for use in horizontal well drilling includes a memory to store computer executable instructions and one or more processors, operatively coupled to the memory, that execute the computer executable instructions to implement a rock strength analyzer configured to determine unconfined compressive strength (UCS) from input parameters, and a well placement module operable to monitor placement of a horizontal well bore in a drilling operation based on the CCS and determined UCS. In certain embodiments, the rock strength analyzer can include a specific energy module for determining specific energy from mechanical and hydraulic specific energy, and a compressive strength module for determining the UCS from confined compressive strength (CCS) as related to specific energy by a mechanical efficiency Em.