Annular Pressure Control Ram Diverter for Underbalanced Drilling
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Solution Overview
Problem
Conventional drilling methods for oil and gas often result in formation damage due to the use of heavy drilling mud, which necessitates hydraulic fracturing to restore porosity and permeability, and pose safety risks due to the need for close proximity to high pressures during underbalanced drilling operations.
Innovation Solution
The Annular Pressure Control Ram Diverter is designed to seal the annulus between the drill pipe and casing, diverting returned drilling and produced fluids into an outer annulus, using flexible seal elements with raised ridges to prevent rotation and ensure effective sealing, thus acting as a primary pressure barrier while the drill pipe is rotating, reducing the need for heavy mud and enhancing safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heavy drilling mud is used to prevent blowouts, then safety is improved, but formation damage occurs due to plugged pores and fractures
Solution Approach 1:
The invention segments the wellbore into two separate annular spaces: an inner annulus for drilling fluid circulation and an outer annulus for hydrocarbon flow. The diverter creates this segmentation by blocking the inner annulus at the surface, forcing returning fluids into the outer annulus. This allows light drilling fluid to be used without plugging formation pores, while still maintaining safety through surface-level annular sealing.
Solution Approach 2:
The annular diverter acts as an intermediary device between the inner and outer annuli. It redirects the high-pressure returning drilling fluid from the inner annulus into the outer annulus, mediating the pressure distribution to prevent formation damage while maintaining blowout prevention capability.
2Reliability
If heavy drilling mud is used to control high pressure zones, then blowout risk is reduced, but hydraulic fracturing becomes necessary to restore permeability
Solution Approach 1:
The invention performs preliminary action by establishing light drilling fluid circulation from the beginning of drilling operations. The annular diverter is installed and configured to maintain underbalanced conditions throughout the drilling process, preventing formation damage before it occurs, thereby eliminating the need for subsequent hydraulic fracturing to restore permeability.
3Object-affected harmful factors
If underbalanced drilling is used to avoid formation damage, then formation permeability is preserved, but safety risks increase due to close proximity to high pressures
Solution Approach 1:
The invention transitions the pressure control mechanism from a downhole location to the surface level. By placing the annular diverter at the surface, the system maintains underbalanced conditions in the wellbore (preserving formation permeability) while controlling high pressures at the surface away from personnel and equipment, thus improving safety without compromising formation integrity.
4Reliability
If conventional annular sealing devices are used, then they cannot effectively seal rotating drill pipe, but rotation of seal elements reduces sealing effectiveness
Solution Approach 1:
The invention employs dynamically adjustable radial positioning of the seal element through a bellows mechanism. The bellows allows the seal element to move radially inward or outward, adapting to the rotating drill pipe's position and maintaining continuous sealing contact. This dynamic adjustment ensures effective sealing during rotation without compromising seal integrity.
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 solution minimizes formation damage, eliminates the need for hydraulic fracturing, and provides a safer drilling environment by containing high pressures below the BOP stack, allowing for hydrocarbon production from natural fracture systems without water, sand, or chemicals, and reducing the risk of blowouts.
Implementation Method 1
flexible seal elements close around the drill pipe while the drill pipe is rotating or stationary to block and seal the annulus between the drill pipe and the casing
Implementation Method 2
raised ridges which form a gripping surface are used to prevent rotation of the seal elements
Data Source
AI summary
Disclosed herein are various embodiments of an Annular Pressure Control Ram Diverter designed to be positioned below the conventional blowout preventer stack, and which will be activated during near balanced drilling operations to seal the annulus between the drill pipe and the casing. Returned drilling fluid and produced fluids are diverted up the annulus between the casing and intermediate casing and through a well head located below an all-inclusive BOP stack. The Annular Pressure Control Ram Diverter employs hydraulic rams to compress a flexible seal around the drill pipe. Some embodiments have an elliptical internal cavity which ensures that the elliptical seal elements cannot rotate. Other embodiments use ridges and grooves on the seal elements and housing to prevent rotation of the seal elements. Doors are provided on each side of the Annular Pressure Control Ram Diverter to permit changing of the seal elements.