Gas Injection Well Evaluation in Carbonate Reservoirs
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Solution Overview
Problem
The existing methods fail to systematically evaluate the difference in gas injection effects among wells in carbonate fractured-vuggy reservoirs, leading to unclear effective characteristics and factors influencing gas injection, resulting in inefficient well performance.
Innovation Solution
A method is developed to classify gas injection wells based on karst types and reservoir types, selecting typical wells for evaluation, comparing production characteristics, and analyzing the reasons for low efficiency by identifying differences in production performance changes, which includes dividing wells into weathering crust cave, weathering crust fracture-vug, fault-controlled cave, and fault-controlled fracture-vug types, and evaluating cumulative oil production to determine inefficient wells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If gas injection is carried out in carbonate fractured-vuggy reservoirs, then oil recovery efficiency is improved, but the difference in gas injection effects among wells becomes large and difficult to evaluate
Solution Approach 1:
The patent segments the evaluation system into multiple independent modules: karst type division, reservoir type identification and classification, production characteristics extraction, and production performance change characteristics extraction. Each module handles a specific aspect of the evaluation, allowing comprehensive analysis of gas injection effects while managing the complexity of large differences among wells through structured, modular assessment.
2Area of stationary object
If the number of gas injection wells is increased, then gas injection coverage is improved, but the complexity of analyzing effect characteristics increases
Solution Approach 1:
The patent transforms the complex analysis problem by changing evaluation parameters from raw production data to standardized characteristics including karst type classification, reservoir type classification, production characteristics parameters, and production performance change parameters. This parameter transformation enables systematic comparison across multiple wells while maintaining comprehensive coverage analysis.
3Measurement precision
If comprehensive evaluation of gas injection effects is performed, then evaluation accuracy is improved, but the time required for analysis increases
Solution Approach 1:
The patent applies preliminary action by pre-establishing karst type division standards, reservoir type identification criteria, and characteristic extraction frameworks before conducting well evaluations. These pre-defined classification systems and evaluation templates enable rapid, accurate assessment of gas injection effects across multiple wells without requiring time-consuming ad-hoc analysis for each well.
Data Source
AI summary
The invention discloses a method for evaluating the difference in gas injection effect of gas injection wells in a carbonate reservoir, aiming at solving the problem that the difference in effect characters of gas injection wells cannot be systematically evaluated in the prior art, and realizing the purposes of systematically and completely evaluating the difference in gas injection effect in the carbonate reservoir and finding out the reason of low efficiency. By means of the invention, reasons for low gas injection efficiency corresponding to different geological classifications are obtained, systematic classification and induction are carried out on the difference in gas injection effect, and gas injection effects are effectively evaluated, so that a sufficient gas injection scheme design basis is provided for subsequent development and production increase, and a significant guiding principle is provided for later-stage gas injection and production increase of the carbonate reservoir.