Comparison of Klinkenberg-Corrected Gas and Liquid Permeability in Kirthar Fold Belt Tight Gas Sands

Abstract

A detailed laboratory study was carried out to investigate the controls and differences between Klinkenbergcorrected gas and liquid permeability. For this reason outcrop core samples were collected from Kirthar fold belt of lower Indus basin, the plugs were horizontally taken, in cylindrical shape having dimension of 3.5-5.32 cm length and with maximum of 3.2 cm diameter. The sample porosity measurements were performed using calculations from grain volume and bulk volume method. For the purpose of comparison, slippage free gas permeability tests using nitrogen gas was measured and liquid permeability of samples was measured using brine (NaCl) of different compositions. The data obtained showed that liquid permeability was lower by an order of magnitude than the permeability of samples measured with gas. However, the gas permeability corrected for Klinkenberg effects showed difference of half an order of magnitude when compared with liquid permeability. Hence the differences in liquid permeability and gas permeability could be described by other mechanism of particles mobilization and dissolution and pore blocking phenomena. Moreover, the obtained data of gas and liquid permeability was then used to develop permeability estimation correlations. The results suggests that there is scatter in the measured values and predicted values of gas and liquid permeability data, which means that such correlations should not be used where accurate liquid permeability values of tight sandstones are needed. Permeability predicted using the existing correlations developed based on gas permeability data lead to an overestimation of permeability also the flow rates might be over predicted within such low permeability reservoirs.

Klinkenberg-Corrected and Water Permeability Correlation for a Sarawak Carbonate Field

“…However, experimental results have shown that Klinkenberg-corrected permeability and its respective water permeability values show significant differences. These observations are in close agreement with previous studies [1,7,[9][10][11][12][13][14][15][16][17][18]. Due to these discrepancies, significant amounts of time and cost have been spent on measuring both permeability values to obtain an absolute liquid permeability value.…”

“…Similar studies [10,14,16,18] have argued that the inaccessibility of water to flow through micro-pores and micro-cracks compared to inert gases caused the difference between Klinkenberg-corrected and water permeability. The ability of inert gases to flow through the double network system (matrix + naturally induced fractures) will cause the gas to cover more area of the pore system to have a higher permeability value [10,16].…”

“…The ability of inert gases to flow through the double network system (matrix + naturally induced fractures) will cause the gas to cover more area of the pore system to have a higher permeability value [10,16]. Water, in turn, will chemically react with clay particles in the core samples, which will form layers of clay-bound water film on the pore throat and micro-crack surfaces that will reduce the effective radius of these pore systems and cause inaccessibility of water to flow through the micro-pores and micro-cracks [10,18]. However, other researchers [14,16] have argued that the values of water permeability were still lower than Klinkenberg-corrected permeability of samples that contains less than 0.1% clay particles.…”

“…A number of studies have been conducted previously [1,7,[9][10][11][12][13][14][15][16][17][18] regarding the relationship between Klinkenberg-corrected and water permeability values, however most of the studies were based on sandstone formations and also very few selective carbonate formations such as Shiuaba carbonate formation in Oman [1], Zelatowa dolomite formation in Poland [10] and selected unnamed carbonates [15]. The correlation established based on sandstone samples cannot be applied on carbonate formations due to the complexity and uncertainty of pore geometry that ranges from big and interconnected pore systems to micro pore structures that only contain intra granular pores or even irregular pore systems such as vugs and pore spaces created from grain dissolution [1,10,24].…”

Morphological and petrophysical evaluation of tight gas resources and energy production in Pakistan

“…The fundamental parts of tight gas construction sand well include rotary drilling of a well bore ultimately completed with a hydraulic fracturing stimulation job. The most current technique is hydraulic fracturing [18] or fracking which was initially introduced by USA and it has resulted in increase of tight gas formation at reduced gas price. Tight gas potential was confirmed through successful drilling by multi fracking at Indus basin of Sindh.…”