A new era of oil well drilling and completions is changing the face of rod pumping forever. Horizontal drilling with multistage hydraulic fracturing often results in very challenging production conditions. Pump placement below the kickoff (i.e. in non-vertical dogleg section), frequent gas slugs, large volumes of flow back frac sand, significant fluctuations in fluid flow rates, and steep decline curves are examples of the common challenges affecting the production of horizontal wells. Even the most sophisticated conventional pump-jack with an AC motor and VFD(variable frequency drive/variable speed drive) does not have the precise rod string control required to help mitigate and resolve many of these complex rod pumping issues frequently associated with horizontal multistage hydraulically fractured wells.
Linear pumping units, and more specifically linear hydraulic pump-jacks, have fundamental differences in geometry and control capabilities. Coupled with the fact that both natural gas and AC drive units support the same functionality, linear hydraulic pump-jacks provide the sophisticated rod string control required by today’s demanding wells.
Linear Hydraulic Pump-Jacks
Operation of a linear hydraulic pump-jack is significantly different than a pump jack. With a linear hydraulic pump-jack, the prime mover is mechanically decoupled from the mechanism that strokes the rod string. The prime mover is used to pressure up hydraulic oil which can then be manipulated as necessary to control the movement of the hydraulic cylinder. With basic linear hydraulic pump-jacks, position sensors are used to define the stroke length. A change in stroke length requires an onsite repositioning of the sensors but does not require a crane or other heavy equipment as with a pump jack. Depending on the hydraulic control valves used, the stroke speed may or may not be configurable. On systems that don’t have proportional flow control, time between strokes can usually be adjusted as a crude way to change the average strokes per minute. One of the key benefits of linear hydraulic pump-jacks is both AC motor and internal combustion engine driven systems have the same rod string control capabilities.
There have been several significant technology advancements with linear hydraulic pump-jacks over the past several years. One of the more significant is the replacement of the position sensors with continuous position measuring systems such as a linear transducer. This enhancement allows the optimization controller to completely customize both the upstroke and the down stroke resulting in very precise rod string control. Combine this with the transition to a proportional control valve (as opposed to an on/off solenoid style valve) and the surface stroke becomes highly customizable and can be tailored to each well’s requirements.
The combination of remote visibility, two way control and adjustable stroking patterns (stroke speed and velocity profile) make the VFD equipped pump jack and linear hydraulic pump-jacks(with position measurement capabilities) the leading contenders for addressing the challenges of today’s horizontally drilled, multi-stage fractured wells.
However, the limitations that even the most advanced conventional pump jacks have related to position control means that linear hydraulic pump-jacks have the best overall feature set for addressing these challenging production scenarios.
Zedi recently introduced an addition to its next-generation, linear lift rod pumping technology. The Zedi SilverJack 8000 artificial lift system is designed to help producers increase efficiencies, lower costs and utilize Zedi’s optimization capabilities on higher-production wells.
This new unit includes all features such as full remote control, precise rod string control, and advanced optimization capabilities，but it is designed for deeper and larger producing wells with its nitrogen gas-assisted lift technology. At up to 45,000 lbs rod string weight, and 240-in. stroke length, the SilverJack 8000 supports twice the capacity of the SilverJack 6000. With its double activating cylinder system, automated N2 storage, closed-loop hydraulic power pack, and sophisticated controller; the SilverJack 8000 offers built-in optimization capabilities that replace expensive and labor-intensive manual processes.
The company’s integrated Access web-based data management system allows all optimization operations to be performed remotely. Released with the new linear lift unit is the new “current status” screen on the data management system, which provides the user a live dashboard of the well’s key parameters necessary to optimize production. Also new is a multiple time-stamped surface and downhole pump cards display , allowing a user to view pump card trends on one screen.
The new hydraulic lift system was designed for the life cycles of modern horizontal wells. Inconsistent flow, gas interference, frac sand and other debris, and a steep decline in production during a well’s transient phase is mitigated by the flexibility to make quick changes and visibility of key well parameters provided by the system. The aim of this intelligent artificial lift system is to maintain peak efficiency while increasing production, and decreasing downtime throughout a well’s entire life cycle.
Key Benefits
Optimization: Make informed pumping parameter changes to stroke length and speed on the fly with an industry leading pump off controller. Optimize production using the controller’s automation features such as Pump Timer and Pump Efficiency Optimizer.
Remote Access: Remotely detect, alarm and resolve common problems with conventional downhole rod pumping equipment. With precise monitoring and trending of rod loads, position and velocity, the system auto-detects / notifies operations and production team members of issues with rod pumping in as little as fifteen minutes.
Flexible Life Cycle Product: Quickly adjust stroke parameters and receive real time data to optimize production during a well’s inconsistent transient phase. The system allows for flexible life cycle programs by first installing a Zedi SilverJack 8000 during a well’s high producing stage, and replacing it with a Zedi SilverJack 6000 at a well’s low producing stage without compromising optimization capabilities.
The Zedi SilverJack Artificial Lift System is a unique combination of a surface hydraulic lift solution integrated with a powerful optimization controller and a flexible web-based data management system (Zedi Access). The integrated solution can remotely detect, alarm and resolve many common problems encountered with conventional downhole rod pumping equipment.
Controller
The SJ8000 Artificial Lift System comes equipped with a graphics based integrated controller to monitor and control all aspects of the lift system. The controller provides the local HMI for viewing and changing all of the many operating parameters of the system. The controller also provides the interface to Zedi Access, Zedi’s web based production data management platform, which provides remote monitoring, alarming and control.
Features
Pump Efficiency Optimizer (PEO) –automatically adjust pump speed to maintain target pump fill
Pump timer options
Estimated production
Traveling and standing valve tests
Remote “Go To” function
Precise rod string control
Y-Day values for diagnostics and alarming
Pump cards
Data Management
Zedi Access, production data management platform, allows monitoring and control of the SilverJack system remotely over the internet. Various Live Data Screens on Zedi Access provide a near real time view to the status of the system. Most of SilverJack’s operating parameters can be changed remotely via Zedi Access, greatly reducing the need to travel to site. Zedi Access also provides the data storage capabilities necessary to develop long term trends and intelligent alarming.
About Zedi
Zedi is a leading oil and gas technology and services company in the field of production operations. Through technology backed by expert consultation and services, we help our customers realize their production potential. With our unique combination of award-winning automation, data management and field and professional services, we offer complete solutions for the challenges our customers encounter.
石油圈
