Application of a Pickering Emulsified Polymeric Gel System as a Water Blocking Agent

Abstract

The conventional methods for controlling excess water production in oil/gas wells can be classified on the basis of the mechanism (pore-blocking mechanism and relative permeability modification) used. Gel systems developed on the basis of a pore-blocking mechanism completely block the pores and stop the flow of both oil and water, whereas a relative permeability modifier (RPM) only restricts the flow of a single phase of the fluid. The gel working on the basis of the pore-blocking mechanism is known as a total blocking gel. An invert emulsified (PAM–PEI) polymer gel is a relative permeability modifier system. The same invert emulsion system is tested as a total blocking gel system in this research work. The dual-injection technique (1st injection and 2nd injection) was used for this purpose. In this research work, the emulsion system was tested at a temperature of 105 °C. The core sections with drilled holes and fractures were used for the core flooding experiments, representing a highly fractured reservoir. The developed emulsified gel system was characterized using a dilution test, an inverted bottle test, microscopic images, and FTIR images. The emulsified polymer gel was tested using a core flooding experiment. After the 2nd injection, the postflood medical CT and micro-CT images of the core sections clearly showed the presence of two different phases in the core section, i.e., the oil phase and the gel phase. The core flooding experiment result indicates that the gel formed after the 2nd injection of the emulsion system can withstand a very high differential pressure, i.e., above 2000 psi. The gel did not allow any oil or water to be produced. Hence, the developed emulsified polymer gel system with the help of a dual-injection technique can be efficiently used as a total blocking gel for high-temperature reservoirs.

Visualizing Conformance Control Mechanisms in High-Temperature Reservoirs: A Microfluidic Analysis of Pickering Emulsified Gel Systems

“…In contrast, oil relative permeability remained unaffected. The ndings align with those observed during core ooding experiments conducted using the same Pickering emulsi ed gel system (Saikia et al, 2021) (Saikia et al, 2019), suggesting that the originally postulated conformance control mechanism only partially holds. While the hypothesis of emulsion separation and aqueous phase gelling was con rmed, the Thin Film mechanism was debunked.…”

“…This temperature exposure spanned a duration of 24 hours. The inherent design of the Pickering emulsi ed gel system ensured that, during this period, the emulsion would undergo phase separation, resulting in the formation of distinct aqueous and oleic phases (Saikia et al, 2021(Saikia et al, , 2019. The aqueous phase subsequently underwent a transformation into a rigid gel structure, serving as a formidable impediment to the ow of the formation water.…”

“…In our previous work, we developed an invert Pickering emulsi ed gel system designed for hightemperature reservoirs. This system, tested as a conformance control mechanism, demonstrated the ability to curtail water production while preserving oil ow (Saikia et al, 2021. Utilizing core ooding experiments and microcomputed tomography (CT) imaging, we postulated the "Thin Film conformance control mechanism" based on experimental data.…”

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In the context of mature oil elds, the management of conformance control and water shut-off stands out as a formidable challenge. Our prior research endeavors (Saikia et al, 2021 have introduced an innovative Pickering emulsi ed gel system tailored for the precise adjustment of relative permeability in high-temperature reservoirs. To optimize the e ciency of this system, a comprehensive comprehension of the underlying conformance control mechanism is deemed imperative.

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Preparation and Characteristics of a pH Intelligent Response Blocking Agent for the Microcrack in the Cement Sheath

“…The technique was used to seal a 109 m long channeling period by perforating the casing, blocking the agent prior to channeling, and implementing the sealing channeling homework. The results showed that the sealing effect was good, and no crossflow occurred between the two layers even after 2 years, demonstrating the technical superiority of the method. , An annulus cement sheath microcrack sealing fluid should have the following characteristics to demonstrate a good performance: (1) it must have good ability to enter the cement sheath microcrack; (2) in the case of dynamic interzonal channeling, the blocking fluid needs to have good retention capacity in the cement sheath microcrack to prevent displacement of the annulus channeling fluid to the low-pressure formation; and (3) the blocking liquid needs to have enough blocking capacity and life after gelling and solidification to ensure the blocking effect. To ensure that the sealing fluid is easy to enter the cement sheath microcrack, the viscosity of the polymer aqueous solution is generally designed to be low, only about 1 mPa·s.…”