Maximizing Unconventional Potential: Streamlining Gas Lift Operations
Unconventional operators face a relentless challenge: managing a multitude of gas lifted wells amidst the dynamic ebb and flow of reservoir behavior. The demand for regular adjustments to optimize gas lift injection at each well exacerbates the strain on resources, manifesting inefficiencies, escalating expenditures, and overlooked production opportunities. Several factors must be balanced simultaneously such as well production potential due to reservoir decline, changes in well behavior, available gas lift capacity, surface compression disturbances, network backpressure, etc.
Enter Xecta’s gas lift optimization solution – a beacon of efficiency amidst the chaos. By leveraging real-time data and hybrid models combining advanced analytics and trusted physics, operators can fine-tune injection rates precisely to match reservoir conditions. This approach heralds a new era of streamlined operations without heuristics or guesswork. With algorithms dynamically calibrating well capacity and recommending injection rates for individual wells or a group of wells fed by shared compressors, operators can now navigate the complex reservoir and surface network landscape with ease, maximizing production potential at every juncture.
The advantages are abundantly clear: significant cost savings of up to 15% and a substantial boost in production up to 10%. Through this transformational shift, operators can unlock the full potential of their wells, ensuring optimal utilization of existing resources. It is not merely about cost reduction; it is about maximizing yields and plotting a trajectory towards enduring success in the perpetually evolving sphere of unconventional operations.
What are the key challenges for gas lift optimization in unconventional plays?
Unconventional wells decline faster, and consequently, the well’s capacity needs to be constantly calibrated. If the wells are spread over a vast area, lack scale, or do not have a central processing facility, gas lift operations need to be managed by mobile field compressors for one or more well pads. Planning to estimate the right number of compressors along with their design specifications with uncertain well production profiles is not trivial. Additionally, as new wells come online, the gas lift injection requirements differ vastly with well’s vintage. Over-injection may lead to higher expenses if buy-back gas is used for injection. Under-injection may lead to reduced benefit from gas injection, especially if injecting at shallower depths or multiple depths. A balancing act is required to characterize the well performance almost daily for large well counts, track available injection gas, and optimally allocate them to maximize total value under constraints.
How does Xecta's solution solve this problem?
Well deliverability (or inflow performance) is updated automatically daily through a hybrid model that combines a reduced physics model based on diffusive time of flight and data-driven model for forecasting transient well productivity index using routine surface measurements. With more frequent updates, the current operating conditions of the well are accurately captured that are essential for gas lift optimization. Gas lift performance curves from multiple wells are simultaneously solved to maximize an economic objective under constraints (total injection gas availability, well injection limits etc.). Fast optimization solvers robustly handle large field scale optimization for thousands of wells. To cap it all, short-term forecasts can be performed on the existing installation and alternate scenarios (different gas lift valve design, tubing / casing design, injection pressure etc.) to plan and support robust decisions.
How do you know that gas lift optimization is adding value to your field?
OK, you have installed a gas lift optimization system in your field. If you are required to continuously feed it with the changes in well inflow performance, or manually analyze the diagnostics for each well, then you are not going to scale efficiently or impact the asset operations. Removing these basic challenges is essential to give back the engineer’s time to focus on other valuable tasks. Once we have a fully automated system making routine open loop recommendations, we still need to implement them in the field. Establishing a ranked list to take the recommendations to the field on a routine basis should become part of the business work process. Despite the best efforts, operating conditions may change in the field, and even if your well is operating optimally on any single day, it could be producing less than what was recommended a few days ago. A simple comparison of gas lift injection rate alone is not representative of the well’s performance without considering changes in tubing pressure, casing pressure, watercut and GOR changes. If your system can quickly compare your actual performance with the path not taken (say the old non-optimal path) through sensitivity analysis, it can help you quantify your value continuously to support your investment decisions.
Is it possible to close the loop on gas lift optimization?
How can we move from open loop to closed loop gas lift optimization? There are 3 major strategies for attaining closed loop control:
1. Setpoint hunting
Basically a trial-and-error procedure is run to periodically change the gas lift target rate up/down and measure the desired objective (e.g. produced oil or liquid rate). This presents some practical challenges in the field as conditions may not always be stable. Instantaneous values without consideration of time lags due to system residence time may lead to false results or suboptimal performance.
2. Setpoint assignment by hybrid model
Use the open loop recommendation of the hybrid model to assign the setpoint of local gas lift injection rate flow controllers. With properly tuned regulatory controllers and careful consideration of how frequently the target rates can be updated, it is possible to achieve fit-for-purpose closed loop operation.
3. Mixed approach
Combine methods 1 and 2 above but initialize the setpoint hunting based on hybrid model’s recommendation and search within a small vicinity to account for any model or data errors.
Final thoughts
In the ever-evolving landscape of unconventional oil and gas operations, efficient gas lift optimization stands as a critical component for maximizing production and reducing costs. By leveraging advanced analytics, hybrid models, and real-time data, operators can fine-tune gas lift injection rates, ensuring optimal well performance and resource utilization. If you are looking for a proven, effective solution to streamline your gas lift operations and unlock the full potential of your wells, we invite you to connect with us. Our expertise and innovative technology can help you navigate the complexities of unconventional plays, ensuring you achieve your production and economic objectives efficiently. Reach out to learn more about how we can support your success in gas lift optimization.
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