Downhole Injection Tool with Collapsible Fluid Containers
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Solution Overview
Problem
Existing methods for sealing off parts of a wellbore or injecting treatment fluids into annular spaces between well tubulars and formations are inefficient, particularly in deviated wells, due to inaccurate delivery of predetermined fluid amounts and mixing ratios, and require heavy machinery.
Innovation Solution
A downhole injecting tool with separate fluid containers and positive displacement pumps, driven by a single motor, where container walls are collapsible under downhole pressure, allowing precise mixing and positioning of fluids without heavy machinery, using ambient pressure to aid fluid displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional bailer systems are used to deliver treatment fluid, then the system is simple in structure, but the delivery precision of predetermined fluid amounts at exact location is insufficient
Solution Approach 1:
The treating fluid is divided into multiple discrete packets, each contained in a separate collapsible container. This segmentation allows precise control over the amount and location of fluid delivery, as each packet can be independently deployed at specific depths along the wellbore annulus, resolving the contradiction between delivery precision and system complexity.
Solution Approach 2:
Multiple fluid packets are pre-loaded into the injection device before deployment. The containers are prepared in advance with specific volumes of treating fluid, and the injection device is configured with multiple injection points at predetermined depths. This preliminary preparation enables precise delivery without requiring complex real-time control mechanisms during operation.
2Power
If heavy pumps and motors are used to inject fluids downhole, then the injection power is sufficient, but the device weight and complexity increase
Solution Approach 1:
The system utilizes the existing downhole environment to perform the injection function. The higher downhole pressure, which normally opposes fluid injection, is harnessed to automatically collapse the containers and force the treating fluid through the injection points. This self-service mechanism eliminates the need for heavy downhole pumps and motors, significantly reducing device weight while maintaining sufficient injection power.
Solution Approach 2:
The high downhole pressure, which is typically a harmful factor opposing fluid injection, is converted into a beneficial force that drives the fluid delivery. The pressure differential between the container interior and exterior causes automatic container collapse and fluid ejection, transforming the adverse pressure condition into the driving mechanism for injection, thereby eliminating heavy machinery requirements.
3Strength
If rigid container walls are used, then the container structural strength is sufficient, but the container cannot collapse under downhole pressure to deliver fluid
Solution Approach 1:
The container walls are designed with dynamic mechanical properties that allow them to transition from a rigid, pressure-resistant state during ascent to a collapsible state during injection. The walls possess sufficient strength to withstand handling and ascent pressures, but are engineered to buckle and collapse when exposed to the higher downhole pressures, thereby enabling fluid delivery through the injection points.
Solution Approach 2:
The mechanical properties of the container walls are designed to change in response to pressure conditions. The walls are constructed from materials or structures that maintain rigidity at lower pressures (during surface handling and ascent) but become unstable and collapse at the higher pressures encountered during downhole injection, thus achieving both structural strength and fluid delivery capability through parameter changes based on environmental conditions.
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
Enables precise and efficient injection of treatment fluids with accurate mixing ratios, ensuring effective sealing in wellbore annular spaces without the need for heavy pumps or motors, improving fluid delivery in challenging well geometries.
Implementation Method 1
exposing at least part of the outside of the fluid container walls to the surrounding pressure in the wellbore, allowing at least part of each of the fluid containers walls to displace within the depositing tool body under forces exerted on the fluid container walls by the surrounding pressure
Data Source
Figure 1
AI summary
Method and apparatus for downhole injecting one or more treatment fluids, and especially for providing one or more seals in an annular space between a well tubular and the surrounding formation or between pipes of a wellbore system, said method comprising the steps of loading the or each treatment fluid separately into one or more fluid containers (2,3) arranged in a injection tool (1), each container comprising container walls surrounding the fluid in the fluid container, and an outlet opening,- lowering the injection tool body into the wellbore or the well tubular to a predetermined position, pumping the fluids from each fluid container into the wellbore or the well tubular.