Managed Pressure Reverse Cementing Choke Valve Control
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Solution Overview
Problem
In subterranean formation operations, reverse cementing methods face challenges with fluid influx into the wellbore due to reduced cementing pressure, which can interfere with cement hydration and lead to lost circulation, making it difficult to maintain zonal isolation and control pressure effectively.
Innovation Solution
The managed pressure reverse cementing (MPRC) process employs a closed pressure loop and choke valve system to control bottom-hole pressure, minimize fluid freefall, and maintain equivalent circulating densities within the pore pressure and fracture gradient, allowing for precise control of fluid flow and location of cement composition during reverse cementing operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If reverse cementing method is used to reduce cementing pressure, then cementing pressure is reduced, but formation fluid influx into wellbore increases
Solution Approach 1:
The patent changes the pressure parameter dynamically during the cementing operation by introducing a kill fluid with higher density than the formation fluid. This creates a pressure gradient that counteracts the formation fluid influx while maintaining the benefits of reverse cementing. The kill fluid is introduced through the drill string and allowed to mix with the cement slurry, creating a controlled pressure environment that prevents fluid influx during cement placement.
2Stress or pressure
If reverse cementing method is used, then cement composition falls down annulus with little pressure, but cement hydration is interfered with by formation fluid influx
Solution Approach 1:
The kill fluid acts as an intermediary substance between the reverse cementing process and the formation fluid influx. It is introduced first down the drill string, mixes with the cement slurry in the annulus, and creates a protective pressure barrier that prevents formation fluids from reaching the cement hydration zone. This intermediary fluid allows the low-pressure reverse cementing to proceed while protecting cement hydration integrity.
3Device complexity
If reduced cementing pressure is applied, then pressure control is simplified, but lost circulation occurs
Solution Approach 1:
The patent implements a feedback mechanism by continuously monitoring wellbore pressure during the cementing operation. Pressure sensors detect changes in pressure that indicate lost circulation or fluid influx, and the system automatically adjusts the kill fluid injection rate or cement slurry pump rate to compensate. This feedback control allows simplified pressure management while preventing lost circulation through real-time adjustments.
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 control over cement placement, reduces operation costs, detects lost circulation in real-time, optimizes zonal isolation, and enables efficient communication with downhole tools through pressure pulses, ensuring integrity and reducing the risk of fluid influx during cementing.
Implementation Method 1
manipulating fluid flow through the choke valve so that an equivalent circulating density of the cement composition and an equivalent circulating density of the treatment fluid are both between a pore pressure of the subterranean formation and a fracture gradient of the subterranean formation
Implementation Method 2
The managed pressure regime is used to control the bottom hole pressure in the wellbore at surface (e.g., to maintain pressure above the pore pressure of the formation) and thus control the influx of formation fluids into the wellbore during a reverse cementing operation
Implementation Method 3
The cement composition may set in the annular space, thereby forming an annular sheath of hardened, substantially imper-meable cement
Data Source
AI summary
Methods and systems including a wellbore having a pipe string extending through a wellhead and into the wellbore, wherein an annulus is formed between the pipe string and the wellbore, an isolation device that closes the wellbore in a closed pressure loop, a choke line in fluid communication with an interior of the pipe string through an outlet port of the wellhead, a choke valve fluidly coupled to the outlet port of the wellhead, wherein the choke valve is manipulable to control fluid flow through the choke line, and a crossover tool in the wellbore to divert incoming fluid from the interior of the pipe string to the annulus.