Stratified Fracturing Crack Length Optimization
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Solution Overview
Problem
In tight reservoirs, the differences in physical properties between layers lead to significant variations in interlayer production rates and contradictions, making it challenging to achieve equilibrium displacement and optimize oil recovery.
Innovation Solution
A method to determine vertical well stratified fracturing crack lengths based on interlayer equilibrium displacement, involving steps to calculate threshold pressure gradients, equivalent well diameters, and optimal crack half-lengths, ensuring all layers are effectively developed and production is balanced.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If uniform fracturing crack length is applied to all layers, then construction complexity is reduced, but interlayer production rate imbalance worsens due to physical property differences
Solution Approach 1:
The patent applies different fracturing crack lengths to different layers based on their specific physical properties (permeability, porosity, thickness). Each layer receives a customized crack length calculation that considers its unique characteristics, thereby optimizing production rate balance across layers while addressing the interlayer contradictions through localized quality adjustment rather than uniform treatment
2Productivity
If stratified fracturing with optimized crack lengths is implemented, then interlayer production balance is improved, but calculation and design complexity increases
Solution Approach 1:
The patent transforms the complex stratified fracturing design problem into a systematic parameter optimization process. By establishing mathematical relationships between crack length, layer thickness, permeability, porosity, and viscosity, the invention provides a calculation method that determines optimal crack lengths through parameter variations. This approach converts qualitative design complexity into quantitative parameter adjustment, making the optimization process more systematic and manageable
3Productivity
If crack lengths are optimized based on interlayer equilibrium displacement, then oil recovery is improved, but measurement and detection difficulty increases
Solution Approach 1:
The patent introduces the concept of 'equilibrium displacement' as an intermediary parameter to bridge the gap between crack length optimization and oil recovery measurement. By using equilibrium displacement as a measurable indicator, the invention provides a practical means to assess whether the optimized crack lengths are achieving the desired interlayer balance and oil recovery goals, thereby reducing the difficulty of detecting and measuring fracturing effectiveness
Data Source
AI summary
The invention discloses a method for determining vertical well stratified fracturing crack length based on interlayer equilibrium development. According to the method, interlayer equilibrium development can be achieved by determining the crack length of fracturing of each layer in the condition that an oil well meets the productivity requirements. The method comprises the following steps: 1) a threshold pressure gradient of each layer is determined; 2) a relationship chart of the crack half-length xf and the equivalent well diameter rwe is established; 3) daily oil production rate per unit thickness Qc meeting the production requirements is calculated; 4) the equivalent well diameter rwe of each layer is calculated according to the daily oil production rate Qc; and 5) the crack half-length xf of fracturing of each layer is calculated according to the equivalent well diameter rwe of each layer.