Method and automated system for control of oil well production and modular skid for use in said method

Abstract

Automated measurement and oil well production control may be achieved by using a vertical separator, the discharge flow of which is continuously adjusted by setting the opening of a control valve, determined by the liquid level inside the separator. The automation of the control method allows real-time measurements of several process variables as well as reduced measurement times and also works as a safety layer for a production process. The control method is independent of well production and is therefore suited to controlling marginal wells.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims priority of U.S. Provisional Application No. 61 / 710,507 filed on Oct. 5, 2012 under 35 U.S.C. §119(e), the entire contents of which are hereby incorporated by reference.FIELD OF THE INVENTION[0002]This invention relates to an automated well production measurement and control system also working as a safety layer for the production process and to a modular skid for its implementation.BACKGROUND OF THE INVENTION[0003]Oil production is the process by which a reservoir fluid is transported to the surface to be separated into oil, gas and water. If necessary, the obtained oil and gas will be treated and conditioned for sale or transport from the field to a petroleum refinery. The so called “upstream operations” consist of the exploration, development and production of crude oil, water and natural gas.[0004]The production process is carried out in a surface installation. This installation includes wells, manifolds, pipel...

AI Technical Summary

Benefits of technology

The present invention provides a method for optimizing oil production from wells by continuously measuring gross production and water cut. This is achieved by building a reliable production allocation system that improves measurement accuracy and understanding of oil field behavior. The method allows for faster control of well production, reduces the time spent in control process, and ensures real-time measurement with reduced error and measurement times. It also facilitates automation of process control and reduces operating expenditures and capital expenditures. Additionally, the invention provides a safety system to ensure a safe process and avoid environment damage.

Problems solved by technology

However, wells in marginal fields generally have production rates with a wide variability and a high water cut, by which in some cases, filling the control tank can be technically challenging, either with the volume produced over a 24 hour or an even longer time period in the case of a low production rate, or with the short time required to fill the tank in the case of a very high production rate.

In case no level sensors are available in the tank, the measurement is dependent on a manual time measurement, which further decreases the validity of the extrapolation procedure.

Yet another source of error is the measuring of the liquid level using a measuring tape.

This is due not only to the error associated with a manual measuring, but also to the fact that the measuring action must be performed with a moving fluid inside the control tank, a situation explicitly counter-indicated in the API MPMS Standards.

In addition, there is a further source of error derived from the control tank calibration chart and its use, given that a manual interpolation must often be performed.

Finally, a single tank measurement is not enough to determine gross production.

Production temperatures of approximately 30 to 40° C. imply a high oil thermal expansion coefficient, which can result in a volumetric error greater than 1%.

While the main advantage of said system relies on the automation of the control procedure, there is limited capability for real-time measurement and monitoring of real-time variables, such as instantaneous and average well production, water cut, fluid density, temperature, etc.

A further disadvantage of said system is the use of a storage tank.

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