Landmark Graphics Corporation

Xiaoqian Huang

Robello Samuel

Samuel Robello

Gabriela M Morales-Ocando

Zexun Zhou

The invention concerns a computer implemented method for underbalanced drilling. In one embodiment, the method includes determining a plurality of gas injection rate versus bottom hole pressure curves for a plurality of liquid injection rates for a specified minimum and maximum gas injection rate and a minimum and maximum liquid injection rate. Next, the method determines a set of four interception curves including a minimum motor equivalent liquid rate interception curve, a minimum vertical liquid velocity intercept curve, a minimum horizontal liquid velocity intercept curve, and a maximum motor equivalent liquid rate intercept curve for a specified minimum and maximum mud motor rate range and a minimum horizontal and vertical annulus velocity.

Method and apparatus for optimized underbalanced drilling

In one embodiment, the invention provides a computer implemented method for determining underbalanced drilling conditions. The method may include determining the number of tool joints in a segment of drill string, where each tool joint has a length and an inner diameter and an outer diameter, determining the total length of all tool joints in a segment of drill string, determining the total length of the segment of drill string excluding the tool length of all tool joints in the segment of drill string, wherein the drill string has an inner diameter and an outer diameter, determining the inner diameter of a segment of wellbore encompassing a segment of drill string, and determining a pressure drop in the segment of wellbore, based on the total length of all tool joints in the segment of drill string.

Lumped data modeling of tool joint effects in underbalanced drilling

One implementation of the disclosure provides a computer implemented method for underbalanced drilling. The implementation may include determining an initial 2D UBD operation envelope based on a set of initial operating points for a selected TVD or time, displaying the initial 2D UBD operation envelope on a computer display, providing at least one data point representing actual data from a well, determining at least one actual UBD operation point using the at least one data point and displaying it on the computer display along with the 2D UBD operation envelope, selecting an optimization parameter, determining a set of optimized operating points based on the optimization parameter, and displaying the set of optimized operating points on the computer display along with the 2D UBD operation envelope.

Optimized UBD operation envelope

The disclosed embodiments include a method, apparatus, and computer program product for monitoring underbalanced drilling operations. For example, one disclosed embodiment is a system that includes at least one processor and at least one memory coupled to the at least one processor and storing instructions that when executed by the at least one processor performs operations for generating a three dimensional tunnel view of an operating envelope of a well as the well is being drilled.

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Katy, TX, United States of America

Xiaoqian Huang