An Effective Accelerated Pulsing Injection Method for Restoring Injectivity in Waterflood Fields with Selective Injection Systems with Side-Pocket Mandrels and Control Flow Valves

Abstract

This paper presents the performance of three water injection wells, INJ-1, INJ-2, and INJ-3, at the Ecopetrol's Yarigui Cantagallo field re-completed with newly designed pulsing selective control valves (P-SCFV). The three wells originally had conventional selective control flow valves (C-SCFV) in side-pocket mandrels. While a total of 31 valves were replaced in seven wells, this paper will focus on the three wells where 12 P-SCFVs were installed and the injection data gathered and interpreted. Enhanced Oil Recovery (EOR) and/or chemical methods are routinely used to improve oil recovery when production levels decline due to reduced formation pressure, poor displacement efficiency, and adverse mobility ratio. For decades, oil production companies with waterflood recovery schemes have employed various types of well completions for water injection, including selective completions with side-pocket mandrels. When an injection zone loses its capacity to admit water, the optimal sweeping capacity will not be reached, and then the operator will not achieve sufficient oil production to maintain profitability. In the Yarigui Cantagallo field 12 P-SCFVs were installed (4 in each injector well), with the objective of overcoming the loss of injectivity in each injection zone due to blockages and permeability decay on the formation face, primarily as the result of calcium carbonate deposition. The new P-SCFVs were run to demonstrate that they could overcome the common problem of permeability decay with the objective that injectivity performance could be increased and sustained over an extended timeframe. The 12 P-SCFVs have been in operation for 12 months, and the comparative results have shown performance optimization that conventional C-SCFVs could not achieve, such as, intervals previously not accepting injection water gradually (after ∼ one month) accepting water from the P-SCFVs. The latter confirms the theoretical and practical efficiency created generated by a flow field that concurrently establishes a repeated pulsed water hammer effect and the creation of numerous vaporization zones, which result in the formation of cavitation bubbles. These vaporization cavities work in consort with the water hammer effect to clear detritus material from the mandrel and formation face giving rise to increased near wellbore permeability.

Renovation method of restoring well productivity using wavefields

“…Разработаны гидравлические инструменты струйного и пульсирующего воздействия [18][19][20], электрогидравлические приборы [21-23], гидродинамические генераторы ГД2В, сейсмические гидросистемы СВС-24/РС27, СВ-27/150Б «Русич», другие приборы [24,25]. Эффективность применения волновых и вибрационных методов обоснована и доказана в работах [26][27][28]. Динамическая пульсация результативна, так как заставляет нагнетаемые жидкости выходить за пределы пути наименьшего сопротивления через процесс дисперсии [6] -рабочая жидкость проникает в пласт более равномерно (несмотря на наличие промытых путей [29]) и глубоко [11].…”