Tracer-Based Back Pressure Metering in Petroleum Wells
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Solution Overview
Problem
Existing methods for estimating formation pressure in petroleum wells during production are inadequate, as they fail to accurately map the reservoir back pressure field due to insufficient time for pressure equalization and varying permeability, leading to inhomogeneous pressure gradients.
Innovation Solution
A petroleum well formation back pressure meter system comprising a tubing with a blank pipe section and packers, where a tracer-conducting channel allows tracer material to pass from a pressure-calibrated bellows into a producing annulus section, enabling the calculation of a pressure gradient to estimate local formation back pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If production continues without shutdown, then productivity is maintained, but measurement precision of formation pressure deteriorates due to insufficient pressure equalization time
Solution Approach 1:
A tracer substance is introduced as an intermediary to indirectly measure formation pressure. The tracer is injected into the annulus, and its concentration in produced fluids is measured to calculate pressure gradients, allowing continuous production while obtaining accurate pressure data through a mediating measurement approach
Solution Approach 2:
The traditional mechanical pressure measurement system that requires well shutdown and direct contact with formation fluid is replaced with a tracer-based chemical/biological measurement system. This substitution allows continuous production while maintaining measurement capability through tracer concentration analysis in produced fluids
2Measurement precision
If tracer material is introduced to measure pressure gradients, then measurement precision improves, but device complexity increases due to additional components
Solution Approach 1:
The tracer injection system is integrated with the existing production well infrastructure. The same production tubing and annulus used for hydrocarbon production are also used for tracer injection and concentration measurement, allowing the system to serve dual purposes of production and pressure measurement without adding separate dedicated equipment
Solution Approach 2:
The produced fluids that naturally flow to the surface during normal production are utilized to transport the tracer from the formation to the measurement point. The production system itself serves the measurement function by carrying the tracer-containing fluids to the surface where concentration can be analyzed
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 system allows for the passive estimation of formation back pressure without shutting down production zones, providing continuous monitoring and dynamic updating of well and reservoir models by correlating tracer flux with pressure gradients, thus improving the accuracy of pressure measurements.
Implementation Method 1
a bellows (5) comprising a fluid tracer (Trb) in pressure communication with said blank-pipe-isolated annulus section (3)
Implementation Method 2
said first packer (1) comprises a tracer-conducting channel (6) allowing through passage of tracer material (Trb)
Data Source
AI summary
A petroleum well formation pressure meter system includes a petroleum fluid conducting tubing in a borehole through a reservoir rock formation. The tubing includes a blank pipe section forming a blank-pipe-isolated first annulus section isolated by a first and a second packer and an adjacent non-blank pipe section beyond said first packer forming a tubing-communicating petroleum producing second annulus section. The first packer includes a tracer-conducting channel allowing through passage of tracer material from an inlet from a bellows including a fluid tracer in pressure communication with said blank-pipe-isolated annulus section, to an outlet to said tubing-communicating annulus section.