Hydraulic Fracturing Complex Fracture Connectors
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Solution Overview
Problem
Existing hydraulic fracturing techniques are limited in creating an optimal effective fracture area in heterogeneous rock formations, restricting well production and hydrocarbon recovery.
Innovation Solution
The technique involves evaluating heterogeneous reservoirs to create complex fractures with fracture connectors, such as step-overs, and controlling their closure to initiate additional fractures, thereby increasing the effective fracture area and connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional hydraulic fracturing techniques are used in heterogeneous rock formations, then the fracturing process is simple and easy to operate, but the effective fracture area is limited and hydrocarbon recovery is restricted
Solution Approach 1:
The fracturing process is divided into multiple stages with different fracturing fluids. A first fracturing fluid creates initial fractures, then a second fracturing fluid with different properties (lower viscosity, different proppant concentration) is used to create additional fractures and extend existing ones. This segmentation allows each stage to target specific fracture characteristics, ultimately increasing the effective fracture area while managing process complexity through structured multi-stage operation.
2Area of stationary object
If multi-stage fracturing with different fluids is implemented, then the effective fracture area increases, but the operation becomes more complex and time-consuming
Solution Approach 1:
The fracturing treatment uses periodic action by alternating between different fracturing fluids in sequential stages. The first fracturing fluid is pumped for a predetermined period to create initial fractures, then the second fracturing fluid is pumped for another predetermined period to create additional fractures. This periodic switching of fluids allows the system to achieve increased fracture surface area through controlled temporal sequencing, with each stage contributing to the overall fracture network development.
3Reliability
If fracture connectors are closed to initiate additional fractures, then the fracture network becomes more complex and connectivity increases, but the control precision requirements increase
Solution Approach 1:
The invention uses parameter changes by varying the properties of the fracturing fluids between stages. The second fracturing fluid has different viscosity and proppant concentration compared to the first fluid. These parameter changes allow the system to control fracture propagation characteristics, enable closure of fracture connectors, and initiate additional fractures. The controlled variation in fluid parameters provides a mechanism to manage fracture network complexity and improve connectivity while addressing control precision challenges through systematic parameter adjustment.
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 enhances well productivity and hydrocarbon recovery by increasing the fracture surface area and connectivity, monitored through acoustic emission monitoring, leading to improved fluid flow and reduced tortuosity issues.
Implementation Method 1
a fracturing treatment material is used to create complex fractures having fracture connectors
Implementation Method 2
monitored through acoustic emission monitoring
Data Source
AI summary
A technique enables improvements in hydraulic fracturing treatments on heterogeneous reservoirs. Based on data obtained for a given reservoir, a fracturing treatment material is used to create complex fractures, which, while interacting with the interfaces and planes of weakness in the reservoir, develop fracture connectors, e.g. step-overs, which often grow for short distances along these planes of weakness. The technique further comprises closing or sealing at least one of the fracture connectors to enable reinitiation of fracturing from the truncated branches, and to subsequently develop additional connectors. As a result, the overall fracturing becomes more complex (more branches and more surface area per unit reservoir volume is created), which leads to an increase in the effective fracture area and improved fluid flow through the reservoir.