Drill Stem Testing Formation Evaluation via Pressure Transient Analysis
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Solution Overview
Problem
Drill stem testing (DST) is expensive and poses environmental and safety risks due to the handling and disposal of substantial hydrocarbon volumes, requiring significant equipment and time, and traditional methods face logistical challenges in efficiently determining formation properties.
Innovation Solution
A formation test system that implements a dual-phase formation test cycle with a DST string deployed as a BHA or wireline assembly, using packers and probes to create isolated zones for fluid intake and injection, allowing for comprehensive measurement of formation properties without the need for extensive equipment and minimizing environmental impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional drill stem testing is performed to determine formation properties, then comprehensive formation data is obtained, but substantial volumes of hydrocarbons are brought to the surface requiring special storage or disposal
Solution Approach 1:
The patent extracts only the necessary information (formation properties) from the formation through minimal fluid intervention. Instead of bringing substantial hydrocarbon volumes to the surface, the system uses pressure transient analysis and limited fluid sampling to obtain comprehensive formation data, thereby extracting value while leaving the bulk of hydrocarbons in the formation.
Solution Approach 2:
The patent changes the measurement parameters from direct hydrocarbon production to pressure transient analysis. By monitoring pressure changes over time during controlled fluid injection and withdrawal, the system determines formation properties (permeability, porosity, fluid saturation) without requiring large volumes of hydrocarbons to be brought to surface, thus achieving accurate measurement with minimal substance extraction.
2Measurement precision
If traditional drill stem testing is performed to determine formation properties, then valuable formation information is obtained, but expensive equipment and significant time are required
Solution Approach 1:
The patent employs a multi-functional testing system that can perform multiple formation evaluation functions (pressure transient testing, fluid sampling, permeability measurement) through a single integrated tool string. This universal approach eliminates the need for multiple separate testing operations and expensive specialized equipment for each type of formation measurement, thereby reducing overall equipment complexity and time requirements while maintaining measurement precision.
3Measurement precision
If traditional drill stem testing is performed to determine formation properties, then comprehensive formation data is obtained, but environmental safety risks increase due to substantial hydrocarbon handling
Solution Approach 1:
The patent converts the potential harm of hydrocarbon handling into a benefit by using minimal controlled fluid intervention. Instead of bringing substantial hydrocarbons to surface where they pose environmental risks, the system uses small volumes of formation fluid for pressure transient analysis and converts this minimal fluid contact into valuable formation evaluation data, thereby eliminating environmental hazards while maintaining measurement quality.
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
The system reduces operational overhead and environmental risks by enabling efficient fluid intake and injection testing, providing detailed formation property data, including permeability and reservoir extent, while minimizing the volume of hydrocarbons brought to the surface.
Implementation Method 1
A first packer and a second packer are deployed on the DST string to form a sealed isolated test zone
Implementation Method 2
The DST tools include pressure sensors and data recorders configured to detect and record pressures, pressure transients, and flow rates
Data Source
AI summary
A test tool attached to test string comprising a fluid conduit is deployed to a test position within a wellbore. The deployment includes hydraulically isolating a portion of the wellbore proximate the test tool to form an isolation zone containing the test position. A fluid inflow test is performed within the isolation zone and an initial formation property and a fluid property are determined based on the fluid inflow test. A fluid injection test is performed within the isolation zone including applying an injection fluid through the test string into the isolation zone, wherein the flow rate or pressure of the injection fluid application is determined based, at least in part, on the at least one of the formation property and fluid property.