Obstruction Element for Deepwater Drill String Pressure Control
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Solution Overview
Problem
In deepwater and ultra-deepwater drilling, existing blowout preventers (BOPs) face challenges in operating optimally due to anomalous internal pressures within drill pipes, which can lead to uncontrolled hydrocarbon blowouts and compromised cutting performance during pipe shearing.
Innovation Solution
A method of assembling drill pipes with an obstruction element that automatically switches between configurations to maintain nominal pressure at the blowout preventer, preventing backflow and ensuring optimal operating conditions for the BOP by interposing the obstruction element downstream of the shearing device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If drilling elements are assembled into a long string for deepwater drilling, then the drilling depth capability is improved, but the risk of anomalous internal pressure and blowout increases
Solution Approach 1:
The drilling string is segmented into multiple sections by inserting obstruction elements at specific intervals. Each segment can independently control pressure, preventing uncontrolled pressure buildup along the entire string length. This segmentation allows the system to maintain reliability while achieving greater drilling depths.
Solution Approach 2:
Obstruction elements are introduced as intermediary devices between the drilling string and the environment. These elements act as mediators that automatically close off the internal passage when anomalous pressure is detected, thereby protecting the system without requiring active intervention from the drilling operation.
2Reliability
If the blowout preventer is positioned on the bottom for deepwater drilling, then the safety coverage is improved, but the ability to control internal pressure during pipe shearing deteriorates
Solution Approach 1:
The obstruction element performs preliminary action by automatically closing the internal passage before the shearing operation commences. This preliminary closure ensures that when the pipe is subsequently sheared by the BOP, no anomalous internal pressure exists to compromise the cutting operation, thereby maintaining ease of operation while preserving safety coverage.
Solution Approach 2:
The obstruction element applies preliminary anti-action by counteracting the potential harmful effect of internal pressure buildup before it can affect the shearing operation. By closing the passage in advance, the system prevents the adverse pressure conditions that would otherwise make pipe shearing difficult or unsafe.
3Reliability
If automatic obstruction elements are inserted in drill pipes, then the safety against blowout is improved, but the device complexity increases
Solution Approach 1:
The obstruction element is designed to be self-activating, automatically closing the internal passage when anomalous pressure conditions occur. This self-service mechanism eliminates the need for complex external control systems, operators, or additional actuators, thereby maintaining relatively simple device architecture while achieving improved blowout protection.
Solution Approach 2:
The obstruction element functions as a disposable safety device that is inserted into the drill pipe for the duration of the operation. Once it has served its protective function (either by closing during a pressure event or remaining open throughout), it is replaced with the next drill pipe section. This approach provides reliable protection without requiring complex, expensive, or reusable mechanisms.
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
The method effectively prevents backflow and ensures the BOP operates under controlled pressure, enhancing safety and the integrity of the drilling process by maintaining pressure equal to or lower than atmospheric pressure, thereby facilitating safe cutting and reducing the risk of hydrocarbon blowouts.
Implementation Method 1
The obstruction element (5) automatically takes a first configuration in which it obstructs said axial hole (21)... preventing backflow (B)... ensures that, inside said drilling element, at wellhead level, there will always be a pressure, lower than the nominal working pressure...
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
Method of assembly of a string (S) of drilling elements for deepwater drilling. Each drilling element comprises an axial through hole (21), through which drilling mud (M) can at least flow, and two connection portions (23) for connecting it in series in said string. The method comprising the following steps: a) assembling a lower portion of the string (15); b) taking a first drilling element (2); c) assembling said at least one first drilling element (2) with other drilling devices in order to create a first section (Tl) of the string ( S ); d) repeating steps b)-c) until said lower portion (15) arrives in the proximity of the blowout preventer (4) or in the proximity of the bottom (G); e) beginning the assembly of second drilling elements (20) while executing a drilling cycle, for the purpose of creating at least a second section (T2) of the string (S); f) repeating step e) until the second section (T2) has reached an extension equal to a desired drilling depth. After step a) and before step b), at least one step s) is carried out, wherein at least one third drilling element (3) is assembled, which comprises at least one obstruction element (5) for preventing a backflow (B) from being generated in said string (S).