Drill String Acid Stimulation for High-Pressure Multilateral Wells
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Solution Overview
Problem
Conventional methods for stimulating subsea hydrocarbon wells face limitations in pressure delivery and require multiple trips and rig time due to the use of coil tubing, which restricts the size of actuator devices and pressure, especially in multilateral drilling.
Innovation Solution
The method involves using a drill string to deliver stimulation fluid and actuator devices through a production liner, utilizing a drill string with a stinger for sealing and larger diameter to allow high-pressure acid injection, reducing the need for annulus pressurization and enabling simultaneous drilling and stimulation operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If coil tubing is used for stimulation in multilateral drilling, then the operation can be conducted through existing tubing, but the tubing diameter is narrow which limits the size of actuator devices and the pressure at which fluid can be delivered
Solution Approach 1:
The drill string is designed to serve multiple functions: it is used for both drilling operations and for delivering stimulation fluid and actuator devices. This eliminates the need for separate coil tubing operations and allows the use of a larger diameter drill string for stimulation, thereby resolving the pressure delivery limitation while maintaining operational ease through the multi-functional drill string system.
2Device complexity
If coil tubing is used for stimulation, then the operation can proceed without additional drilling equipment, but the narrow tubing restricts actuator size and pressure delivery
Solution Approach 1:
The drill string performs dual roles as both a drilling tool and a stimulation fluid delivery system. By integrating the stimulation function into the existing drill string infrastructure, the patent eliminates the need for separate coil tubing equipment while providing a larger diameter conduit for actuator and fluid delivery, thus reducing overall device complexity requirements.
3Strength
If production tubing is used for stimulation, then the annulus can be pressurized to support the tubing, but the pressure at which fluid can be delivered is still limited
Solution Approach 1:
The drill string is utilized for both drilling and stimulation operations, eliminating the need to rely on annulus pressurization to support production tubing during stimulation. The drill string's larger diameter and structural design enable direct high-pressure fluid delivery without the constraints imposed by production tubing limitations.
4Productivity
If multiple trips and rig movements are made for multilateral drilling and stimulation, then each zone can be completed thoroughly, but rig time is extremely expensive and the process is time-consuming
Solution Approach 1:
The patent combines the drilling and stimulation operations into a single integrated process using the drill string. By merging these previously separate operations, the system eliminates multiple rig trips and movements, thereby reducing rig time and associated costs while maintaining the ability to complete each zone thoroughly through the drill string's delivery capability.
Solution Approach 2:
The drill string serves multiple functions including drilling, transporting actuator devices, and delivering stimulation fluid. This multi-functionality allows all operations to be performed through a single equipment system, eliminating the need for separate coil tubing units and multiple rig movements, thus significantly reducing time loss while maintaining operational effectiveness.
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 rig time and enhances pressure delivery, allowing larger actuator devices and higher fluid flow rates, thereby optimizing the stimulation process in subsea hydrocarbon wells.
Implementation Method 1
injection of acid, especially if the formation is of a type which lends itself to being opened up by acid, e.g. if the rock of carbonate composition (chalk or limestone)
Implementation Method 2
a male seal element, e.g. stinger, at its distal end, the male seal element being complementary to the female sealing element and capable of sealing with the female sealing element
Data Source
AI summary
The invention relates to a method and apparatus for performing acid stimulation of a hydrocarbon well (1), especially in a multi-lateral branched well system. In the first lateral (8), after installation of the production liner (9) with ball-activated completion equipment (10), acid stimulation is performed through drill string (21) which is introduced into the well and which seals with the production liner (9) by means of a stinger (22) and polished bore receptacle (23) before introduction of acid.