Water Permeability Reduction Under Flow-Induced Polymer Adsorption

Summary For some polymer gels applied in reservoirs to control water flow, a favorable disproportionate permeability reduction (DPR) occurs in which permeability to water is reduced to a much greater extent than it is to oil. Permeability reduction in sandpacks by partially hydrolyzed polyacrylamide-chromium acetate gels was studied as functions of gel composition and the pressure gradients imposed on the gels. For the range of parameters studied, increased gel composition increased the factors by which the permeabilities to water and oil were reduced. Increased gel composition also increased selectivity, a measure of the water-permeability reduction with respect to oil-permeability reduction. Applied pressure gradients during steady-state flows had little effect on oil permeability and a moderate effect on water permeability. Material balances on phases and components in the sandpacks provided insights into mechanisms responsible for the development of flow channels through gelled sandpacks and mechanisms contributing to favorable DPR. Increased pressure gradient during channel development decreased the selectivity of the treatment. Introduction High water production is a major concern in mature hydrocarbon reservoirs. Costs of handling and disposing of water produced from oil reservoirs often shorten the life of a production well. Disposal of the water is also an environmental concern. In order to reduce water production, polymer gels have been used to modify the mobility of water and oil in petroleum reservoirs. When some gels are placed in a petroleum reservoir, permeability reduction occurs to a much greater extent for water than for oil. This phenomenon is known as favorable DPR. Reduced permeability to water can lead to decreased production of water, and sometimes increased oil production, thereby prolonging the useful life of the reservoir. Results reported in the literature have shown that the application of several polymer gel systems can result in DPR. Mechanisms for DPR have been debated, and the magnitude of the effect has been unpredictable from one application to another. Mechanisms for DPR that have been proposed and studied by several researchers are shown in Table 1. The usual method to study DPR is to saturate a porous medium with gelant, allow time for gelation to occur, and then inject oil and water to steady-state conditions and determine permeabilities at 100% fractional flow of each fluid. One aspect of this procedure that most of these experimental works do not describe or examine is the process that occurs when oil or water is first injected into the gel-treated porous media. It is our experience that the medium has very little permeability at the start of injection and that considerable time is required for the injected fluid to develop channels or flow paths through the system before a steady state is approached.

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Disproportionate Permeability Reduction Due to Polymer Adsorption Entanglement

10.2118/68972-ms ◽

2001 ◽

Cited By ~ 9

Author(s):

H.H. Al-Sharji ◽

C.A. Grattoni ◽

R.A. Dawe ◽

R.W. Zimmerman

Keyword(s):

Polymer Adsorption ◽

Permeability Reduction

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Effects of Formation-Water Salinity, Formation Pressure, Gas Composition, and Gas-Flow Rate on Carbon Dioxide Sequestration in Coal Formations

SPE Journal ◽

10.2118/185949-pa ◽

2017 ◽

Vol 22 (05) ◽

pp. 1530-1541 ◽

Cited By ~ 3

Author(s):

Ahmed Farid Ibrahim ◽

Hisham A. Nasr-El-Din

Keyword(s):

Relative Permeability ◽

Flow Rate ◽

Water Permeability ◽

Co2 Sequestration ◽

Absolute Permeability ◽

Co2 Injection ◽

Permeability Reduction ◽

Formation Pressure ◽

Coal Surface ◽

Effective Water

Summary Carbon dioxide (CO2) sequestration in coal seams combines CO2 storage with enhancing methane (CH4) recovery. The efficiency of CO2 sequestration depends on the coal-formation properties and the operating conditions. This study investigated the effects of the sodium chloride (NaCl) salinity of coal-seam water, injection flow rate, injected-gas composition, and CO2 state (formation pressure) on CO2 sequestration in coal formations. Coreflood tests were conducted on nine coal cores to simulate the injection of CO2 into coal formations. The change in the effective water/coal permeability after CO2 injection was measured. A commercial simulator was used to match the pressure drop across the core from the experimental study by adjusting the relative permeability curves. Moreover, permeability dynamic measurements were conducted to estimate the absolute permeability reduction caused by coal swelling. The effective water permeability in the tested coal decreased during CO2 injection because of its adsorption onto the coal surface, coupled with a reduction in the relative water permeability. As salt concentration increased, the change in the pressure drop across the core increased, but this effect decreased as the formation pressure increased. Higher formation pressure and lower nitrogen (N2) concentrations led to further permeability reduction as a result of the higher CO2 adsorption onto the coal surface. Furthermore, as the injection flow rate increased, the contact time of CO2 at the coal surface decreased. Hence, the CO2 adsorption to the coal matrix decreased, and thus the difference in the effective water permeability slightly decreased. CO2 injectivity in fully water-saturated formations increased initially as the gas relative permeability increased, then the injectivity decreased as a result of matrix swelling and absolute permeability reduction. Moreover, the water salinity in coal formations decreased the overall gas relative permeability and increased the water relative permeability. Similar behavior occurred in the presence of N2. It is derived from these observations that the injection of CO2 into highly volatile bituminous coal seams for CO2 sequestration purpose is more efficient as the salt concentration increases, especially at high injection pressures.

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The drainage system performance in peat soil with permeability reduction

E3S Web of Conferences ◽

10.1051/e3sconf/20199107013 ◽

2019 ◽

Vol 91 ◽

pp. 07013

Author(s):

Andrey Nikitin ◽

Olga Zaborskaya

Keyword(s):

Water Permeability ◽

Peat Soil ◽

Drainage System ◽

Operating Experience ◽

Size Composition ◽

Normal Operation ◽

Filling Material ◽

Permeability Reduction ◽

Drainage Systems ◽

Over Time

Construction in waterlogged areas requires special design solutions and expensive site preparation works. Operating experience shows that the efficiency of drainage systems in peat soil decreases over time. This article describes factors to be taken into account when designing drainage systems in peat soil. It also summarizes the results of the laboratory surveys for peat and filling material permeability reduction over time. We used a laboratory box to study water permeability over time. In the experiment, we used poorly decomposed peat of natural structure and compacted peat. The study found that the water inflow into the drainage system decreased 1.5 to 1.7 times in the course of filtration. The greatest peat permeability reduction was recorded at the initial stage. The article demonstrates how the grain-size composition of sand used as backfilling affects its water permeability. In order to ensure normal operation of drainage systems in peat soil, one must consider the reduction of peat water permeability over time and clogging of sand filling when designing the said systems.

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Effect of Polymer Adsorption on Permeability Reduction in Enhanced Oil Recovery

Journal of Petroleum Engineering ◽

10.1155/2014/395857 ◽

2014 ◽

Vol 2014 ◽

pp. 1-9 ◽

Cited By ~ 38

Author(s):

Saurabh Mishra ◽

Achinta Bera ◽

Ajay Mandal

Keyword(s):

Oil Recovery ◽

Polymer Concentration ◽

Polymer Adsorption ◽

Mobility Control ◽

Special Focus ◽

Permeability Reduction ◽

Solution Ph ◽

Residual Resistance ◽

Polymer Injection ◽

Hydrolyzed Polyacrylamide

In order to reduce the permeability to water or brine, there is a possibility of polymer injection into the reservoir. In the present work, special focus has been paid in polymer [partially hydrolyzed polyacrylamide (PHPA)] injection as a part of chemical method. Tests were conducted in the laboratory at the ambient temperature to examine the reduction in permeability to water or brine in the well-prepared sand packed after the polymer injection. The experiments were performed to study the effect of polymer adsorption on permeability reduction by analyzing residual resistance factor values with different concentrations of polymer solutions. The rheological behavior of the polymer has also been examined. The experimental results also indicate that the adsorption behavior of polymer is strongly affected by salinity, solution pH, and polymer concentration. To investigate the effect of polymer adsorption and mobility control on additional oil recovery, polymer flooding experiments were conducted with different polymer concentrations. It has been obtained that with the increase in polymer concentrations, oil recovery increases.

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