Free Hydrocarbon Estimation in Sedimentary Rock
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Solution Overview
Problem
Current methods, such as the ROCK-EVAL device's Shale Play method, fail to accurately distinguish between free and retained hydrocarbons in unconventional source rocks, which is crucial for estimating the oil potential and deciding on exploitation.
Innovation Solution
A method involving two complete artificial maturation processes, one on a rock sample and another on isolated total organic matter, with pyrolysis under an inert atmosphere followed by oxidation, allows for the differentiation of free and retained hydrocarbons by measuring CO and CO2 releases at specific temperature sequences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods (ROCK-EVAL Shale Play method) are used to estimate hydrocarbons in source rocks, then the overall process is simple and quick, but the measurement precision for distinguishing free versus retained hydrocarbons is insufficient
Solution Approach 1:
The method segments the hydrocarbon population into two distinct categories: free hydrocarbons (released during pyrolysis of the rock sample) and retained hydrocarbons (released during pyrolysis of isolated organic matter). By separating the analysis into two distinct maturation processes applied to different samples, the method achieves precise distinction between hydrocarbon types while maintaining procedural clarity
Solution Approach 2:
The method extracts the organic matter from the rock matrix to create a separate sample for analysis. This extraction allows the retained hydrocarbons to be measured independently from the free hydrocarbons, enabling accurate quantification of each fraction through comparative pyrolysis experiments
2Reliability
If a single maturation process is used on rock samples, then the procedure is simple and fast, but the reliability of hydrocarbon quantity estimation is insufficient
Solution Approach 1:
The method performs preliminary separation of organic matter from the rock matrix before the main hydrocarbon analysis. This preliminary action (extraction and isolation of organic matter) enables subsequent parallel maturation experiments that yield both free and retained hydrocarbon data simultaneously, improving reliability without proportionally increasing time investment
Solution Approach 2:
The method applies the same maturation protocol to two different samples (rock sample and isolated organic matter sample), creating comparable datasets that can be mathematically processed to determine free hydrocarbon content. This copying approach ensures consistent measurement conditions while enabling accurate differentiation of hydrocarbon fractions
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 approach enables precise quantification of free hydrocarbons, improving the estimation of hydrocarbons available for production and enhancing the assessment of oil potential in unconventional source rocks.
Implementation Method 1
heating the sample according to a first heating sequence under an inert atmosphere, and continuously measuring a representative quantity of the hydrocarbon-containing compounds released during at least a part of the first heating sequence
Implementation Method 2
heating a residue of the sample originating from the first heating sequence according to a second heating sequence under an oxidizing atmosphere, and measuring a representative quantity of CO and a representative quantity of CO2 released during the second heating sequence
Data Source
AI summary
A method for determining a parameter representative of a quantity of hydrocarbon-containing compounds present in free form within a sedimentary rock, wherein a first sample representative of the sedimentary rock is obtained and a second sample which is representative of isolated total organic matter in the sedimentary rock is obtained by eliminating a free mineral portion part of the second sample. Each of the samples are processed according to steps comprising heating the sample according to a first heating sequence under an inert atmosphere, and continuously measuring a representative quantity of the hydrocarbon-containing compounds released during at least a part of the first heating sequence. A representative quantity of CO and a representative quantity of CO2 released during a second heating sequence is measured. The parameter representative of the quantity of hydrocarbon-containing compounds present in free form within the sedimentary rock from the first and second samples is determined.