Estimation of Average Reservoir Pressure and Completion Skin Factor of Wells that Produce Using Sucker Rod Pumping

by
Manuel de Almeida Barreto Filho, Ph.D.

University of Texas at Austin, 2001
Co-Supervisors: Augusto L. Podio and Kamy Sepehrnoori

Evaluation of pumping wells using data obtained from transient pressure tests is often uneconomical. As an alternative, this work proposes the development of a system to estimate average reservoir pressure and completion skin factor by matching the measured variation of annular fluid level versus time in pumping wells that are alternately turned on and turned off (time-clock operation), with annular fluid level versus time theoretically calculated and presented as type curves. In order to accomplish this objective, a numerical model was developed that integrates the performance of the pumping system, the wellbore and reservoir, using refined and accurate sub models including a damped wave equation modeling the surface unit and rod motion, a hydrodynamic pump performance model and a multiphase wellbore model with fluid segregation. The uniqueness of the numerical solution was verified.

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