Volume fracturing and drainage technologies for low-pressure marine shale gas reservoirs in the Ordos Basin

Fu, Suotang; Wang, Wen‐Xiong; Li, Xianwen; Xi, Shengli; Hu, Xifeng; Zhang, Yanming

doi:10.1016/j.ngib.2021.07.001

Cited by 7 publications

(2 citation statements)

References 2 publications

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“…The average starting pressure of the Upper Paleozoic in the Ordos basin is 1.2, and the formation pressure of the Ordovician should be higher. The formation pressure coefficient of low pressure marine shale gas reservoir in Ordos Basin is increased from 0.7 to 1.88 by injecting 30,668 m 3 fracturing fluid and 800 m 3 liquid nitrogen and the test well ZP1 realizes 94 days of continuous gas-liquid two-phase flow [26,27].Gas energy-enhanced fracturing tests have been carried out in 4 shale gas dessert areas in the central-northern part of the western Ordos Basin, which has effectively increased the formation pressure and achieved a breakthrough in the exploration of marine shale gas. Because the literature does not specifically mention the formation pressure data of each well after pressurization, it can not be compared with the data calculated in this paper, but the development idea used is consistent [27].…”

Section: Discussionmentioning

confidence: 99%

Classification method of shale gas analytic stages and its application

Keying

Kai

2023

SN Appl. Sci.

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China is rich in shale gas resources, and improving the oil recovery of shale gas wells is one of the hot issues in the current research. The production of shale gas wells releases shale gas by reducing formation pressure by repeated fracturing. In this paper, the curvature of shale desorption efficiency curve is analyzed to study the pressure suitable for formation shale gas release. According to the inflection point and stagnation point of the curvature curve, the starting pressure, sensitive pressure and turning pressure are obtained. the curvature curve can be divided into four stages: sensitive desorption, rapid desorption, slow desorption and inefficient desorption. In actual exploitation, shale desorption cannot go through all four desorption stages, and can be determined according to the ratio of $$V_{L} /P_{L}$$ V L / P L . When the ratio is greater than 2.59, there are four integral stages in shale desorption, and the larger the ratio is, the longer the sensitive desorption stage is. At 1.0–2.59, there are three stages of desorption; at 0.54–1, there are only two stages; below 0.54, there are only low efficiency stage. The isothermal adsorption study on the core samples of the Upper Paleozoic in Yulin area of Ordos Basin shows that the shale of the Upper Paleozoic in the study area has more starting pressure and turning pressure, and less sensitive pressure, and the ratio of $$V_{L} /P_{L}$$ V L / P L is between 0.5 and 2.0. Generally, the isotherm adsorption curve can be divided into three stages: fast desorption, slow desorption and low efficiency desorption. The low efficiency desorption stage contributes the most to the productivity of Upper Paleozoic shale in this area, and the slow desorption is supplementary. According to the desorption stage and pressure node in shale mining, the formation pressure can be appropriately reduced to improve shale gas recovery efficiency.

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Section: Discussionmentioning

confidence: 99%

Classification method of shale gas analytic stages and its application

Keying

Kai

2023

SN Appl. Sci.

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“…Unconventional oil and gas mostly reside in tight reservoirs, the permeability of which are generally in the range of micro-Darcy to nano-Darcy. Due to the tight nature of these reservoirs, large-scale fracturing is often required to enhance the formation permeability to facilitate the oil and gas production. − At present, volumetric fracturing technology is one of the main methods of exploiting unconventional oil and gas resources. Slickwater fracturing fluid is more conducive to the formation of a complex fracture network in unconventional reservoirs, which is the key to implementing volume fracturing.…”

Section: Introductionmentioning

confidence: 99%

Preparation and Performance Evaluation of a Variable Viscosity Friction Reducer Suspension with High Salt Tolerance and Low Damage

Shi

Sun

et al. 2022

Energy Fuels

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In view of challenges such as the long dissolution time of powder friction reducers in high-salinity water, poor environmental friendliness of water-in-oil (W/O) emulsion friction reducers, and the poor proppant-carrying capacity of conventional slickwater, a novel variable viscosity friction reducer suspension (EACM) with high salt tolerance, low damage, and strong proppant-carrying capacity was prepared by dispersing salt-tolerant polymer powder in alcohol solvents. The solubility, drag reduction ability, viscoelasticity, proppant-carrying capacity, temperature and shear resistance, and gel breaking ability of EACM were investigated. The results showed that the best solvent for the friction reducer suspension was polyethylene glycol 400, in which EACM exhibited a rapid dissolution rate with a thickening rate of 89.5% within 2 min. Due to the synergic effect between fumed silica and polyamide wax as antisedimentation agents, both at a concentration of 2.0 wt %, the EACM could remain stable for 60 days. EACM showed an excellent drag reduction performance at both low and high viscosities in 100 000 mg/L salt brine. Specifically, a drag reduction of up to 72.4% was obtained using 0.21 wt % EACM (4.65 mPa s), and a 60.8% drag reduction was achieved using 1.0 wt % EACM (35.5 mPa s). When the concentration increased from 0.13 to 1.0 wt %, the EACM solution changed from viscous to elastic; the spatial network structure of the solution became more compact, and the proppant-carrying capacity was enhanced. The viscosity of 1.6 wt % EACM solution could be maintained at 55.9 mPa s after shearing at 90 °C for 120 min at a shear rate of 100 s −1 . EACM solution also exhibited the advantages of easy breaking and low residue. This paper provides guidance for the design and selection of a novel friction reducer suspension in the oil and gas industry.

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Synthesis and performance evaluation of low‐damage variable viscosity integrated drag reducer

Fan,

Yu,

Shu

et al. 2024

J of Applied Polymer Sci

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To solve problems such as inadequate proppant carrying capacity, a complex viscosity changing process, and limited environmental friendliness associated with traditional slick water fracturing fluids, a variable viscosity friction reducer called Jianghan friction reducer (JHFR) with low damage, high drag reduction, and strong proppant‐carrying capacity is prepared by inverse emulsion polymerization. The properties of JHFR are investigated by viscometer, JHFR‐II high‐temperature and high‐pressure slick water drag reduction rate tester, surface tension meter, and JHCQ Core dynamic damage evaluation device. The result shows that the dissolution time of JHFR is less than 120 s. The drag reduction of 0.08 wt% JHFR (4.83 mPa s) is 80.3%. When the concentration of JHFR increases from 0.08 to 0.8 wt %, the viscosity of the JHFR increases from 4.83to 97.41 mPa s. After sheared at 90°C and 170 s−1 for 60 min, the viscosity of 0.8 wt% JHFR still maintains 51 mPa s. The damage rate of JHFR to core matrix permeability is lower than 30%. JHFR also shows the advantages of easy breakage and low residue. It provides guidance for the design and selection of fracturing fluid for unconventional oil and gas reservoir development.

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Volume fracturing and drainage technologies for low-pressure marine shale gas reservoirs in the Ordos Basin

Cited by 7 publications

References 2 publications

Classification method of shale gas analytic stages and its application

Classification method of shale gas analytic stages and its application

Preparation and Performance Evaluation of a Variable Viscosity Friction Reducer Suspension with High Salt Tolerance and Low Damage

Synthesis and performance evaluation of low‐damage variable viscosity integrated drag reducer

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