Formation Damage through Aqueous Phase Trapping In Gas Reservoirs

Paiaman, Abouzar Mirzaei; Moghadasi, Jamshid; Masihi, Mohsen

doi:10.2118/129637-ms

Cited by 20 publications

(4 citation statements)

References 3 publications

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“…Residual PAM has not been identified as a significant challenge for reuse, although the degraded polymer could lead to plugging of small fractures and formation pores which would reduce gas and oil permeability. [160][161][162] A variety of treatment technologies are potentially available for removal/degradation of PAM, although the performance of these systems has yet to be evaluated, particularly for PAM fragments. Previous studies have shown high rates of PAM degradation by oxidation.…”

Section: Discussionmentioning

confidence: 99%

Polyacrylamide degradation and its implications in environmental systems

et al. 2018

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High molecular weight (10 6-3 × 10 7 Da) polyacrylamide (PAM) is commonly used as a flocculant in water and wastewater treatment, as a soil conditioner, and as a viscosity modifier and friction reducer in both enhanced oil recovery and high volume hydraulic fracturing. These applications of PAM can result in significant environmental challenges, both in water management and in contamination of local water supplies after accidental spills. This paper provides a short review of current applications of high molecular weight PAM, including the potential for PAM degradation by chemical, mechanical, thermal, photolytic, and biological processes. Methods for treating wastewater containing partially degraded PAM are then discussed along with issues related to the potential toxicity and mobility of PAM in the environment after disposal or accidental release.

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Section: Discussionmentioning

confidence: 99%

Polyacrylamide degradation and its implications in environmental systems

et al. 2018

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“…Davis and Wood used the volume water percentage (BVW) to describe water blockage and divided the water blockage degree into three levels: the potential water blockage sensitivity is not obvious, the potential water blockage sensitivity may exist, and the potential water blockage sensitivity is serious. Paiaman et al proposed the use of the CAPT index to judge the water blockage damage degree of gas reservoirs. However, these indicators can only evaluate the degree of static water blockage.…”

Section: Introductionmentioning

confidence: 99%

Quantitative Prediction Method of Liquid Retention Based on Nuclear Magnetic Resonance

Mao

Lai

et al. 2022

Energy Fuels

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For tight gas reservoirs such as water-sensitive and low permeability, the incoming fluids are the most important external factors that damage oil and gas reservoirs. The liquid phase retention has become an important influence factor of production capacity. At present, the water blockage damage degree is often used to evaluate the liquid phase retention degree. Therefore, based on the study of fractal dimension by a NMR (nuclear magnetic resonance) experiment, using the existing formula of the fractal calculation of the relative permeability curve, this paper improves the relevant formula for calculating water blockage damage for NMR and studies the relative permeability curve and water blockage damage rate of tight gas reservoirs. According to the calculation results, the fractal dimension of the samples is 2.3551− 2.7417, and the average value is 2.492. This shows that the micro-pore structure of core samples is relatively complex with medium heterogeneity. Through the analysis of the relative permeability curve, it can be deduced that the rocks in this block have strong hydrophilicity, and the gas−water two-phase seepages in this block strongly interfere with each other. Besides, the comparative analysis shows that the method of calculating water blockage damage rate is accurate and the average error is only 4.59%. The average damage degree of water blockage in this block is moderate water blockage damage. The results of the parametric analysis also demonstrate that irreducible water saturation and pore-throat structure relationship are the key factors governing the water blockage degree, which determines the damage degree of foreign liquid retention to reservoirs.

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“…However, large amount of liquid retain in the formation after flowback [13,48]. Thus, the reservoir permeability was damaged severely, which reduce the effective gas flowing during production [49][50][51][52][53][54]. The same water saturation in tight gas reservoir has more impact on permeability than conventional gas reservoir [55].…”

Section: Introductionmentioning

confidence: 99%

Analyzing Tight Sand Characteristics and Its Influence on Aqueous Phase Removal by Gas Displacement

Meng

Shen

et al. 2019

Geofluids

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Tight sand gas is an important unconventional natural gas. Liquid filtration plays a main role in the formation damage. Flowback rate is closely related to the formation permeability recovery. Usually, the more flowback rate is, the better the permeability recovery is. In order to research the factors that influence the liquid flowback, the tight sand characteristics and gas displacement have been investigated. Some experiments were carried out, including porosity, permeability, XRD, casting thin section, SEM, stress sensitivity, rock expansion, and gas displacement. The results are shown as follows. Taiyuan formation has average high clay content than H8 formation. Illite is the main clay in Taiyuan formation; chlorite is the main clay in H8 formation. From the casting thin section, the rock has strong compression. Taiyuan formation has large pore. However, H8 formation mainly has small cracks. Through the SEM, there are many micro- to nanocracks as well as some pores in these two formations. In some cases, cracks penetrate the clays. From the permeability stress sensitivity, these tight sands have strong stress sensitivity. Permeability decreases quickly with increasing confining pressure. In the rock expansion experiment, the tight sand has less expansion rate compared with shale gas rock and volcanic gas rock. Rock expansion rate has positive relationship with clay content. In the gas displacement experiment, usually the higher the clay content, the lesser the liquid flowback. Some samples have high clay content. However, it has high flowback rate, which may account for good pore connection. Through the above study, the flowback rate has negative relationship with clay content and positive relationship with pore size, pore connection, and displacement pressure. In order to increase tight gas production in the study area, the formation should have high flowback rate and less liquid retention. Therefore, clay expansion preventing additives should be added into the fracturing liquid to reduce the liquid retention. The quick flowback should be implemented after hydraulic fracturing for reducing the interaction between liquid and rock. At the same time, the drawdown pressure should keep in a certain value to reduce stress sensitivity.

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Formation Damage through Aqueous Phase Trapping In Gas Reservoirs

Cited by 20 publications

References 3 publications

Polyacrylamide degradation and its implications in environmental systems

Polyacrylamide degradation and its implications in environmental systems

Quantitative Prediction Method of Liquid Retention Based on Nuclear Magnetic Resonance

Analyzing Tight Sand Characteristics and Its Influence on Aqueous Phase Removal by Gas Displacement

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