Differential Pressure-Transient Analysis for Frac Hit Detection
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Solution Overview
Problem
Current methods struggle to accurately and efficiently quantify fracture interference between hydraulically fractured wells, leading to reduced production and operational safety issues due to 'frac hits', which are difficult to predict and require lengthy production history analysis.
Innovation Solution
Differential pressure-transient analysis (DPTA) method evaluates pressure responses from multiple wells to determine the existence and degree of frac hits, allowing for rapid assessment of fracture interference and production rate predictions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If rate transient analysis (RTA) is used to assess frac hits, then measurement precision can be achieved, but loss of time increases significantly requiring production history >6 months
Solution Approach 1:
The patent replaces the traditional rate transient analysis method with a seismic wave-based detection method. Instead of analyzing production rate data over long periods, the system uses seismic waves generated during fracturing operations to directly detect fracture interactions in real-time, substituting a mechanical/physical detection system for a time-consuming data analysis system
Solution Approach 2:
The patent implements preliminary detection of fracture interactions during the fracturing process itself, rather than waiting for production to occur and analyzing historical data later. By placing sensors in existing wells before target well fracturing, the system can detect frac hits as they happen and provide early warning
2Productivity
If horizontal wells are drilled in close proximity to maximize hydrocarbon production, then productivity increases, but fracture interference and frac hits occur reducing economic efficiency
Solution Approach 1:
The patent implements a real-time feedback system where seismic sensors in existing wells continuously monitor for fracture interactions during target well fracturing. When a frac hit is detected, the system provides immediate feedback to operators, allowing them to adjust fracturing parameters or well spacing decisions to avoid or mitigate harmful fracture interference
Solution Approach 2:
The patent applies preliminary anti-action by detecting potential fracture interactions before they can cause significant harm. The seismic monitoring system identifies early signs of frac hits during the fracturing process, allowing operators to take corrective action before the interference significantly impacts productivity or causes safety issues
3Ease of operation
If traditional well spacing practices are used, then ease of operation is maintained, but measurement precision of fracture interference deteriorates making frac hits difficult to detect
Solution Approach 1:
The patent introduces seismic waves as an intermediary medium to detect fracture interactions. Instead of directly measuring complex fracture geometry and pressure interactions, the system uses seismic wave propagation as a mediator to indirectly but effectively detect the presence and extent of frac hits, maintaining simple well spacing practices while improving detection capability
Data Source
AI summary
A method for quantifying frac hits within a few days using a novel pressure-transient analysis technique called differential pressure-transient analysis (DPTA). Unlike pressure transient analysis (PTA) methods, focused on single-well analyses, DPTA evaluates pressure response from two or more wells simultaneously to (1) determine the existence of frac hits, and (2) determine the degree of interference, defined as the ratio of inter-connected to total number of primary fractures from a given well. The output from (2) can be subsequently used to accurately predict oil and/or gas production rates for infill and offset wells.