Method of removing wellbore fluid from well and water removal well

Abstract

A method for removal of fluid from a subterranean formation is provided, the method including the steps of: providing a wellbore from the surface to within the formation: providing a pump in the wellbore capable of removing fluid from the wellbore to a surface location; establishing a pump performance function as pump curves; measuring at least one variable that establishes where the pump is operating on the pump curve; determining the differential pressure across the pump from the measured variable and the digital power and the flow rate; determining the suction side pressure from the differential pressure across the pump and the vertical height of the annular fluid column of the fluid column above the pump; determining the suction side fluid level from the suction side pressure and the fluid density.

Description

RELATED CASES[0001]This application claims the benefit of U.S. Provisional Application No. 61 / 882,121, filed on Sep. 25, 2013, which is incorporated herein by reference.BACKGROUND[0002]The invention relates to a method of removing wellbore fluid from a wellbore and a wellbore for removing fluid from a formation. In particular, the present invention may be utilized to produce methane from coal bed methane seams by removal of water from the formation[0003]Coal bed methane is typically produced by pumping water from a coal bed methane seam to reduce the hydrostatic pressure, and thereby permit methane adsorbed on the coal to be released. Typically the seams from which methane may be produced by this method are fairly shallow, at depths from three hundred to eight hundred meters. The wellbores provided to accomplish this are generally simple and inexpensive, but removal of water is a significant cost Generally, pumps are provided in ratholes that extend below the coal seam, and the pump...

AI Technical Summary

Benefits of technology

The present invention provides a method to control a submersible pump using easily measured surface variables, without the need to measure the liquid level in the wellbore. Additionally, using a variable speed pump can minimize energy loss and prevent pump cycling.

Problems solved by technology

The wellbores provided to accomplish this are generally simple and inexpensive, but removal of water is a significant cost Generally, pumps are provided in ratholes that extend below the coal seam, and the pumps are operated until the liquid level in the wellbore is low.

Constantly starting up and shutting down the pump results in short lifes of the pumps, and having to operate with more than a minimal amount of water in the wellbore can reduce production of methane.

Operators therefore attempt to optimize profits by allowing water levels to build for a time period, but not to an extent where excessive production is lost because of additional hydrostatic pressure being put on the coal.

A large number of coal bed methane wells need to be provided for a commercial development, and therefore the cost of each well is important to the economics of the development.

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