Borehole Completion Planning from Rock Failure Modes
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Solution Overview
Problem
Hydraulic fracturing operations often fail to fracture unconventional hydrocarbon reservoirs due to the rock failing to break above the breakdown pressure, leading to time and financial losses, and the inability to produce stored hydrocarbons due to low permeability.
Innovation Solution
A method and system to determine principal in-situ effective stresses and mechanical properties of the rock surrounding a borehole, using models to calculate breakdown and yield pressures, and design a completion plan based on deformation mechanisms and failure modes to optimize hydraulic fracturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulic fracturing operation raises the pressure of borehole fluid above breakdown pressure, then the rock should fracture, but the rock may fail to fracture above the breakdown pressure
Solution Approach 1:
The patent applies preliminary action by performing rock characterization and mechanical property determination before the hydraulic fracturing operation. The system calculates breakdown pressure and yield pressure using rock data obtained from characterization systems, allowing the completion design system to pre-determine the optimal fracturing pressure range. This preliminary analysis ensures that the subsequent fracturing operation operates within the correct pressure parameters to achieve reliable fracturing and hydrocarbon production.
2Loss of time
If the rock does not fracture above breakdown pressure, then time and money are lost, but the completion plan has not been optimized
Solution Approach 1:
The patent implements feedback by using rock characterization data and mechanical property measurements to continuously refine the completion design. The system receives rock data from characterization systems, determines mechanical properties, calculates breakdown and yield pressures, and uses this information to optimize the completion plan. This feedback loop ensures that the fracturing operation parameters are adjusted based on actual rock properties, preventing time loss from unsuccessful fracturing attempts.
3Productivity
If the rock has low permeability, then hydrocarbons cannot be produced from the rock, but fracturing the rock should increase permeability
Solution Approach 1:
The patent applies parameter changes by modifying the physical state and permeability parameters of the rock through controlled fracturing. The completion design system uses calculated breakdown and yield pressures to determine the optimal pressure range for fracturing, which changes the rock's permeability parameter from low to high. This parameter change enables hydrocarbons to flow from the rock formation through the created fractures to the borehole, significantly improving production capability.
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
Enables effective fracture of the rock by accurately predicting fracture pressures, reducing time and cost, and enhancing hydrocarbon production by designing appropriate completion plans.
Implementation Method 1
A hydraulic fracturing operation may be performed to induce fractures within the rock such that the stored hydrocarbons may be produced from the rock to the surface of the earth via a borehole. Typically, the hydraulic fracturing operation raises the pressure of a borehole fluid above a breakdown pressure to fracture the rock.
Implementation Method 2
The rock may elastically deform based on the elastic model and may plastically deform based on the plastic model.
Implementation Method 3
The rock may elastically deform based on the elastic model and may plastically deform based on the plastic model.
Implementation Method 4
The failure mode of the rock is determined by comparing the breakdown pressure and the yield pressure. If the breakdown pressure is less than or equal to the yield pressure, the failure mode of the rock is brittle fracture.
Implementation Method 5
If the breakdown pressure is greater than the yield pressure, the failure mode of the rock is ductile fracture.
Data Source
AI summary
Methods and systems are disclosed. Methods may include obtaining, from a rock characterization system, rock data for a rock that surrounds an interval of a borehole within a formation and determining principal in-situ effective stresses and mechanical properties of the rock using the rock data. The methods may further include determining, using a first model, a breakdown pressure for the rock using the principal in-situ effective stresses and the mechanical properties and determining, using a second model, a yield pressure for the rock using the principal in-situ effective stresses and the mechanical properties. The methods may still further include determining a deformation mechanism and a failure mode of the rock by comparing the breakdown pressure and the yield pressure and designing, using a completion design system, a completion plan for the borehole based on the deformation mechanism, the failure mode, and the breakdown pressure.