Subsea Injection Pressure Control Using Bottomhole Reservoir Feedback
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Solution Overview
Problem
Existing solutions for controlling fluid pressure during injection into subterranean reservoirs fail to provide accurate pressure measurements and control at the reservoir level, leading to potential damage from over-pressurization or under-pressurization, as they only measure pressure before the fluid enters the well, not within the reservoir.
Innovation Solution
A system with subsea templates and pressure gauges at the drill hole openings measures bottom pressure directly in the reservoir, allowing for real-time control of fluid injection through choke valves based on pre-set flow rates and tolerances to maintain optimal pressure and prevent reservoir damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure is controlled based on measurements before fluid enters the well, then injection flow can be controlled, but actual reservoir pressure and damage risk cannot be accurately monitored
Solution Approach 1:
The patent transitions from surface-level pressure measurements to subsurface reservoir pressure measurements by deploying pressure gauges at the bottom of injection wells and in the reservoir itself. This spatial dimensionality change enables direct monitoring of reservoir pressure conditions, providing accurate information about actual pressure states and preventing over-pressurization damage.
2Productivity
If injection pressure is increased to maintain flow rate, then productivity is improved, but reservoir damage risk increases
Solution Approach 1:
The patent implements a feedback control system where pressure gauges continuously monitor reservoir pressure, and this information is used to adjust injection rates in real-time. When reservoir pressure approaches critical thresholds, the system automatically reduces injection rates to prevent formation damage, while maintaining optimal productivity within safe pressure limits.
3Measurement precision
If multiple pressure gauges are deployed in the reservoir, then pressure control precision is improved, but system complexity increases
Solution Approach 1:
The patent divides the reservoir monitoring system into multiple segmented pressure gauge locations, each monitoring specific zones or formations. This segmentation enables targeted pressure control for different reservoir compartments, allowing precise management of complex reservoir dynamics through distributed measurement points rather than a single centralized gauge.
Data Source
Figure 1a
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AI summary
There is provided a fluid handling system (200), method and non-transitory computer-readable storage medium for controlling the flow and injection pressure of fluid to be injected into a subterranean void (150) at an offshore injection site (100) for long term storage. A subsea template (120) is configured to receive fluid from a fluid storage is arranged on a seabed (130) in connection with at least two well heads for a respective at least two drill holes (140) to a subterranean void (150). For each drill hole (140), a first pressure gauge (122) is located at the bottom opening (142) of the drill hole (140) for measuring a bottom pressure, P B. The subsea template (120) comprises a utility system configured to cause received fluid to be injected into the subterranean void (150) and having a valve system (121 ) with at least one choke valve for each drill hole (140) configured to control the injection of fluid into the subterranean void (150) in response to control commands (Ccmd) based on a respective preset desired flow rate for each drill hole (140) and a pre-set lowest allowable flow rate from the fluid storage. The control commands (Ccmd) may further be configured to cause the at least one choke valve of each drill hole (140) to choke back if the current bottom pressure for the drill hole (140) reaches a pre-set maximum pressure value, P MAX.