Maritime Drilling Fluid Reverse Circulation Without Riser
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Solution Overview
Problem
Drilling deepwater wellbores faces challenges such as the need for heavy and large drilling riser joints, high fluid circulation system capacity, and high operational costs due to the use of subsea pumps with low reliability and complex systems, which prolongs the drilling process and increases costs.
Innovation Solution
The method involves drilling a marine wellbore using fluid reverse circulation without drilling riser tubulars, where the return of fluid with gravels occurs through the drill string and clean fluid injection is made through the well annulus, eliminating the need for subsea pumps and concentric columns, and allowing operations to be performed in parallel with the BOP connected, utilizing dual activity probes for increased efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If drilling riser tubulars are used for deepwater drilling, then the drilling operation can be performed, but the weight and dimensions of the equipment increase significantly
Solution Approach 1:
The invention extracts and eliminates the drilling riser tubulars from the deepwater drilling system, replacing them with a simplified configuration that uses the drill string itself for fluid return. This removes the heavy 32,000 lb riser joints and 23m long tubulars while maintaining drilling capability through an alternative fluid circulation path.
Solution Approach 2:
The invention inverts the traditional fluid circulation direction by returning drilling fluid through the drill string interior rather than through the annulus. This reverse circulation approach eliminates the need for riser tubulars as fluid return conduits, fundamentally changing the circulation architecture to reduce equipment weight.
2Reliability
If drilling riser tubulars are used to fill the riser volume, then the circulation system can operate, but the fluid volume required increases to 470,000 liters
Solution Approach 1:
The invention extracts the riser tubulars from the circulation system, eliminating the 470,000 liter fluid volume requirement that was necessary to fill the riser. By removing the riser as a fluid containment structure, the system only requires sufficient fluid for actual drilling operations, dramatically reducing the quantity of circulating fluid needed.
3Productivity
If subsea pumps are used for fluid return, then the drilling operation can proceed, but the system reliability decreases due to movable parts
Solution Approach 1:
The invention extracts and eliminates subsea pumps from the system by utilizing the drill string interior as the fluid return path. This removes movable parts and pumping equipment from the subsea environment, relying instead on the natural circulation and pressure differentials to return fluid through the drill string, thereby significantly improving system reliability.
Solution Approach 2:
The system uses the drill string itself as the fluid return conduit, allowing the drilling equipment to serve multiple functions. The drill string not only delivers drilling fluid to the bit but also returns it to the surface, eliminating the need for separate pumping equipment and reducing system complexity.
4Reliability
If drilling riser tubulars are used, then the drilling operation can be performed, but the operational time and costs increase due to lowering operations
Solution Approach 1:
The invention extracts the drilling riser tubulars from the system, eliminating the time-consuming lowering and positioning operations that previously took several days in deepwater. By removing this equipment, the system reduces the critical path activities and accelerates well construction while maintaining operational capability through alternative means.
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 reduces operational time and costs, enhances system reliability, releases load capacity and space occupied by risers, and allows simultaneous operations with dual activity probes, significantly reducing the time and cost of well construction while minimizing risk exposure.
Implementation Method 1
The return of the fluid with gravels occurs through the interior of the drill string and the injection of clean fluid is made through the annular of the well
Data Source
AI summary
The present invention refers to a method of drilling a marine wellbore with fluid reverse circulation without using drilling riser tubulars. In reverse circulation drilling, the fluid return with gravels occurs inside the drill string (17) and the injection of clean fluid is done through the annular of the well, so that, having a rotating head over the BOP (19), or inside it, the use of riser tubulars as a flow line for the fluid return with gravels is disposed, using instead the drill string (17).For the kill and choke lines, as well as for fluid injection, rigid or flexible lines can be used, eliminating the need to use drilling risers, thus releasing large load capacity and space on the probe. The method of this invention also eliminates the need for large volumes of fluid to fill entire riser tubulars. The entire operation can be done without the need for subsea pumps or concentric columns. Additionally, the invention makes the operation of lowering the drilling riser tubulars unnecessary, which lasts for days and has a high cost. Finally, for dual activity probes, the arrangement allows the use of the two towers even after connecting the BOP (19), something that is not possible with the use of drilling riser tubulars. Therefore, operations such as mounting and lowering the casing in the water depth can be carried out in parallel with the drilling of the phase, allowing a significant additional gain of time.