Tab.1

Statistics of rock fabrics and lithologic types in the Ma-5 member, Jingbian field"

Fig.1

Tectonic division of the Ordos Basin and locations of the Jingbian, Sulige, and Yulin gas fields[12]"

Tab.2

Pore-structure statistics for the Ma-5 member, Jingbian field"

Fig.2

Epoxy-impregnated cast thin sections of reservoir rocks from the Ma-51+2 sub-member, Jingbian field"

Tab.3

Equivalent pore-throat distribution statistics for core from well I, Yulin field"

Tab.4

Petrophysical parameters of different reservoir types in the Ma-51+2 sub-member, southern Jingbian field"

Fig.3

Plan-view sedimentary microfacies distribution in the $\mathrm{Ma}-5_{1}^{2}(\mathrm{a})$ and $ \mathrm{Ma}-5_{1}^{3}(\mathrm{~b})$sub-layers, southern Jingbian Field"

Fig.4

Ordovician （Lower Paleozoic） gas accumulation model, Jingbian field"

Tab.5

XRD analysis of blockage samples 1 and 2 from the southern Jingbian field"

Fig.5

SEM morphology of blockage deposits from the southern Jingbian field"

Tab.6

Elemental composition of blockage deposits from the well G50-6, Jingbian field"

Fig.6

Sequential states of blockage material from well G50-6: as-collected, after water removal, and after oil removal"

Fig.7

Schematic of water-blocking damage: （a） original connate-water state of the gas reservoir; （b） after invading-fluid incursion; （c） after reservoir-water encroachment, with displacement to bound （irreducible） water"

Fig.8

High-temperature, high-pressure relative-permeability curves for cores with permeabilities of 0.014×10-3 μm2 （a）, 0.032×10-3 μm2 （b）, 0.041×10-3 μm2 （c）, 0.051×10-3 μm2 （d）, 0.093×10-3 μm2 （e）, and 0.150×10-3 μm2 （f） ;（g） relationship between core gas-phase permeability and water saturation[33]"

Tab.7

Characteristics and genesis of scaling in different gas fields of the Changqing area [35-38]"

Tab.8

Analysis of corrosion-scale formation and blockage mechanisms in gas wells [39-41]"

Tab.9

Unblocking measures and operational parameters for a single well in the Ma-5 sub-member"

Fig.9

Process flow diagram for deep-reservoir de-blockage technology"

Fig.10

Process flow diagram for low dosage multi cycle de-blockage"

Tab.10

Dissolution efficiency of de-blockage formulations at different blend ratios in the Jingbian field"

Fig.11

Process flow diagram for the compressor-assisted gas-lift composite de-blockage technology"

Fig.12

Operational flow diagram for coiled-tubing sand-jet washing:（a） run in coiled tubing;（b） inject low-density wash fluid;（c） inject liquid nitrogen;（d） rotary jetting with the washing head;（e） foamer-assisted performance enhancement;（f） sand-laden flowback"

Fig.13

Microfluidic demonstration of tailored wetting order and contact-angle tuning on modified channel surfaces[32]"

Fig.14

Mechanistic diagram of water-lock removal by the composite water-lock breaker"

Fig.15

Mechanistic diagram of CO2-foam assisted de-blockage"