Petroleum Well Injection System Tension Control
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Solution Overview
Problem
Existing petroleum well injection systems face challenges with free-hanging intervention cables, which can lead to over-pull and over-push, causing damage and safety risks due to inadequate tension measurement and control, especially when using rigid or stiff cables like carbon fiber rods or coiled tubing, and lack precise measurement of backward tension.
Innovation Solution
A petroleum well injection system that incorporates a bending restrictor loop with ball joints, a springy tension compensator arc, and a frequency-controlled electric motor to manage cable tension, along with load cells and guide arch load cells for precise measurement and control of backward tension, ensuring the intervention cable operates within safe limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a free-hanging cable run is used between cable drum and well injector, then the system requires large free space and creates danger to personnel, but using a rigid intervention cable with limited minimum bending radius reduces flexibility and increases vulnerability to damage
Solution Approach 1:
A guide arch is introduced as an intermediary component between the cable drum and well injector. The guide arch provides a predetermined curved path that guides the rigid intervention cable, ensuring the cable maintains its minimum bending radius while being fed or reeled in. This mediator allows the rigid cable to operate safely without direct contact with the drum surface, preventing damage while maintaining operational capability.
2Reliability
If hydraulic motors with pressure relief valves are used to control the injector, then the system can limit maximum pressure and torque, but the response time is slow and the system cannot quickly react to sudden tension changes
Solution Approach 1:
The hydraulic motor system is replaced with an electric motor that directly drives the cable drum. This substitution eliminates the hydraulic fluid transmission delay and pressure relief valve response time. The electric motor can immediately adjust its torque output in response to tension changes detected by sensors, providing fast and precise control of the intervention cable during both feeding and retrieval operations.
3Measurement precision
If no backward tension measurement is implemented, then the system structure is simpler, but the system cannot accurately detect over-pull or over-push conditions
Solution Approach 1:
A backward tension measurement system is implemented using load cells or force sensors that continuously measure the tension in the intervention cable as it is fed from or reeled into the well. This feedback is transmitted to a control system that compares the measured tension against predetermined safety thresholds. When over-tension conditions are detected, the system automatically triggers an alarm and stops the motor, preventing cable damage or well incidents.
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 system effectively prevents damage from over-pull and over-push by continuously monitoring and controlling tensile stress, reducing motor torque when limits are exceeded, and providing faster response times compared to hydraulic systems, ensuring safer and more reliable operation of intervention cables.
Implementation Method 1
a sensor (151) for measuring the injector force or the tension that the drive belts (15) applies to the intervention cable (2)
Implementation Method 2
a frequency-controlled electric motor (11) to exerting a force (Fu, Fd) upwards or downwards to the string (2)
Implementation Method 3
drive belts (15) driven by an electric motor (11) to exerting a force (Fu, Fd) upwards or downwards to the string (2)
Data Source
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AI summary
The present invention solves more of the above mentioned problems. The invention is a petroleum well injection system for an intervention cable (2) with a well tool (3) ran into or out of a well (0) during a well operation, wherein the system comprise the following features: - a blow out valve BOP (03) connected to a well head (02) at a well (0), - a lock chamber (7) at the BOP (03) arranged to contain the well tool (3) before and after the well operation, - an injector (1) for the intervention cable (2), with drive belts (15) driven by an electric motor (11), and a sensor (151) for measuring the injector force or the tension (aD) that the drive belts(15) applies to the intervention cable (2), - a guide arch (12) at the injector (1), wherein the intervention cable (2) runs taut over the guide arch (12) to a first end (21) of the closed bending restrictor channels (20). - a guide arch load cell (45) arranged to measure the backward tension (OB ) between an intervention cable (2) the first end (21) of the bending restrictor channel (20) - wherein the other end (22) of the bending restrictor channel (20) is connected to a drum frame (92) with a motor (98) running a drum (91) for the intervention cable (2).