Horizontal Well Interval Control via Electric Valves
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Solution Overview
Problem
Existing methods for treating oil reservoirs with horizontal and lateral bores face challenges such as inability to perform targeted acid treatment, high costs due to tripping operations, and limitations in injecting active agents like acid or mud, especially with sliding actuators sensitive to pressure jumps and limited independent production intervals.
Innovation Solution
The implementation of pilot-operated electric valves with a special adapter to enable independent inclusion or exclusion of production intervals, allowing for precise injection of active agents and improving valve reliability by excluding sliding actuators, while using packers to separate permeability zones and a centrifugal pump to manage pressure and fluid extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sequential injection of oil-based spacer fluid and inhibited aqueous solution of hydrochloric acid is performed, then formation zone treatment is achieved, but targeted acid treatment for certain borehole intervals becomes impossible
Solution Approach 1:
The wellbore is divided into multiple separate intervals using packers, with each interval equipped with its own injection valve. This segmentation allows independent acid treatment of specific zones while maintaining the ability to treat the entire formation sequentially, resolving the contradiction between comprehensive treatment and targeted intervention.
Solution Approach 2:
Electric valves are installed at each interval to dynamically control fluid injection. These valves can be opened or closed based on treatment requirements, enabling both sequential injection across all intervals and targeted treatment of specific zones, thus achieving adaptability without sacrificing treatment effectiveness.
2Reliability
If tubing string is lowered to perforation interval for treatment, then formation zone treatment is possible, but high costs occur due to large amount of tripping operations
Solution Approach 1:
Packers and electric valves are pre-installed in the tubing string before lowering it into the wellbore. This preliminary configuration eliminates the need for repeated tripping operations during treatment, as the system is already prepared for both sequential and targeted injection modes, significantly reducing time loss while maintaining treatment capability.
3Ease of operation
If sliding actuators are used in electric valves, then valve operation is simple, but reliability decreases due to sensitivity to pressure jumps
Solution Approach 1:
The sliding actuator mechanism is replaced with a rotating actuator system that uses rotational motion instead of linear sliding. This substitution eliminates sensitivity to pressure jumps while maintaining operational simplicity, as the rotating mechanism is inherently more resistant to pressure fluctuations in the wellbore environment.
4Adaptability or versatility
If multiple independent production intervals are created, then selective treatment capability improves, but device complexity increases
Solution Approach 1:
Each electric valve is designed to perform multiple functions: it can inject acid, close off intervals for selective treatment, and enable sequential injection modes. This multi-functionality reduces the need for additional specialized components, thereby limiting device complexity growth even as the number of independent intervals increases.
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 solution allows for independent control of production intervals, reliable active agent injection, and reduced risk of equipment damage, enabling efficient treatment of oil reservoirs with improved assembly operations and reduced costs by avoiding cable twisting and high-pressure issues.
Implementation Method 1
separating the formation with the help of packers into the intervals based on the geophysical survey results
Implementation Method 2
A centrifugal pump is arranged at a calculated distance from the well mouth for the production fluid recovery through the tube side
Implementation Method 3
The pipe string with the cable, two or more electric valves with the pressure (and temperature) sensing devices
Data Source
AI summary
A horizontal segment of the well is bored preliminarily, the segment being constructed through a formation with various permeability zones. A geophysical survey is conducted, and the number of oil recovery intervals of various categories and their lengths are determined. A tail pipe (or tail filter) of the casing string with packers and drive shoe are lowered down and installed in the horizontal segment. A pump and an assembly on the pipe string are lowered down into the well, the assembly including electric valves with pressure and temperature sensors, cabling, and packers separating the annular space of the well. The assembly packers are arranged opposite to the casing string packers. While lowering down the assembly, some electric valves are opened, and another electric valve (for circulation) is closed. Data from the sensors are monitored. The formation segments are periodically treated by injecting a chemical composition into the corresponding intervals.