Water Occurrence and Its Influencing Factors in Tight Gas Reservoirs

Tight reservoirs hold a vast natural gas in Ordos Basin, and efficient development of these resources can offset the energy shortage. Due to low-porosity low-permeability, hydraulic fracturing becomes necessary tap its resources. After fracturing, large amount fluid fills pore space near fracture, which will influence production. This study focused on water occurrence tight influencing factors. Samples were selected from Upper Paleozoic Taiyuan Shihezi Formations Basin. The main experiments include porosity, permeability, mineral composition, nitrogen adsorption (NA), mercury intrusion porosimetry (MIP), nuclear magnetic resonance (NMR), high-speed centrifugation, so on. was divided into movable saturation (Smov) irreducible (Sirr). Further, controlled by capillary force (Sirrc) big pores small throat (Sirrl). In both Formations, has negative relationship with average diameter, positive specific surface area. Sirrl median pore-throat diameter Formation, but weak Formation. Sirrc area Sirrc parameters