Non-stop Circulation System for Bottom Hole Pressure Control
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Solution Overview
Problem
Existing drilling systems fail to maintain constant bottom hole pressure during all phases of drilling, particularly during drill pipe loading and tripping, leading to hydraulic fracturing and other hazards due to pressure fluctuations.
Innovation Solution
A method involving a top drive and circulation coupler system that supplies drilling mud at varying pressures, with a back pressure pump to maintain constant bottom hole pressure by controlling flow through chokes and valves, ensuring consistent pressure throughout drilling operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If drilling mud is supplied at high pressure through top drive during drilling operations, then bottom hole pressure is maintained to prevent kick and absorption phenomena, but pressure fluctuations occur during drill pipe loading and tripping operations causing hydraulic fracturing
Solution Approach 1:
The system divides the drilling fluid circulation path into two independent channels: (1) a primary path through the drill string for normal drilling operations, and (2) a secondary path through the circulation coupler and back pressure pump for pressure maintenance during tripping operations. This segmentation allows independent control of each path to meet different operational requirements.
Solution Approach 2:
The circulation coupler acts as an intermediary device that connects the drill string to the back pressure pump system. It enables the back pressure pump to inject drilling fluid into the drill string or annulus, serving as a mediator to maintain pressure when the primary circulation system is interrupted during pipe loading.
2Reliability
If additives are added to increase fluid density in the annulus to control fluid release, then kick and absorption phenomena are prevented, but it takes too long to get additives into the annulus and may exceed formation fracture pressure
Solution Approach 1:
The system replaces the chemical method (adding density-increasing additives) with a mechanical method (back pressure pump) to rapidly increase bottom hole pressure. The pump can immediately inject drilling fluid to raise pressure without the time delay associated with mixing and circulating additives through the entire annulus.
Solution Approach 2:
The back pressure pump system is pre-positioned and ready to operate, allowing immediate pressure maintenance when needed during tripping operations. This preliminary preparation eliminates the response time delay that would occur if additives needed to be mixed and circulated into the annulus.
3Reliability
If standard well-control systems with choke valves and sensors are used to control entry and exit flows, then kick and absorption phenomena are managed, but the systems do not provide control over flows when pumps are shut down during drill pipe loading
Solution Approach 1:
The circulation coupler system serves multiple functions: (1) it enables continuous circulation during normal drilling, (2) it provides pressure maintenance during tripping operations, and (3) it allows drill string rotation during pipe loading. This multi-functionality makes the system adaptable to all phases of drilling operations, not just standard drilling.
Solution Approach 2:
The system dynamically adapts its operation mode based on the drilling phase: during normal drilling, the top drive pump supplies fluid through the drill string; during tripping, the back pressure pump maintains pressure; during pipe loading, the circulation coupler enables continuous circulation and rotation. This dynamic adaptability ensures pressure control throughout all operations.
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 maintains constant bottom hole pressure during drilling, preventing hydraulic fracturing and ensuring safe and efficient drilling operations by regulating mud flow and pressure across all phases of drilling.
Implementation Method 1
pumping drilling mud into the wellbore annulus by a back pressure pump, wherein the bottom hole pressure at the bottom of the wellbore is maintained substantially constant during all steps
Implementation Method 2
flow of drilling mud out of a wellbore annulus is restricted by a choke to hold pressure in a wellbore annulus
Implementation Method 3
a hydrostatic column of drilling mud typically extends from the bottom of the hole up to a bell nipple of a diverter assembly on the drilling rig. Annular fluids exit the bell nipple where solids are removed, the mud is processed, and then prepared to be re-delivered to the subterranean wellbore through the drill string
Data Source
AI summary
A method for maintaining a constant bottom hole pressure during wellbore drilling operations, the method comprising supplying drilling fluid to the drill string via a top drive at a first pressure while flow of drilling fluid out of a wellbore annulus is restricted by a choke to hold pressure in a wellbore annulus and supplying drilling fluid to the drill string via the top drive at a second pressure lower than the first pressure and to a circulation coupler at a third pressure while flow of drilling fluid out of a wellbore annulus is restricted by a choke to hold pressure in the annulus, wherein the sum of the second and third pressures is approximately the same as the first pressure. The method also comprises supplying drilling fluid to the drill string via the circulation coupler at the third pressure while pumping drilling fluid into the wellbore annulus by a back pressure pump, wherein the bottom hole pressure at the bottom of the wellbore is maintained substantially constant during all steps of supplying drilling fluid to the drill string.