Study of the Effect of Movable Water Saturation on Gas Production in Tight Sandstone Gas Reservoirs

Abstract

The movable water saturation of tight sandstone reservoirs is an important parameter in characterizing water production capacity, and there is a great need to understand the relationship between movable water saturation and water production characteristics. However, movable water behavior in this context remains unclear. In this study, four groups of tight sandstone cores from the Sulige gas field are measured to understand the movable water saturation characteristics. Then, the effects such as reservoir micropore throat, clay mineral and physical properties on movable water saturation are analyzed, and the movable water saturation and water production characteristics are discussed. The results show that higher movable water saturation will result in a greater amount of water in the gas drive. There is a critical pressure difference of the gas drive, and a large amount of movable water will flow out. Movable water saturation is independent of the porosity, permeability and initial water saturation, while it is closely related to the reservoir micropore throat and clay mineral content. Movable water is mainly distributed in the medium and large pores; the larger the proportion of such pores, the higher the degree of movable water saturation. A lower mineral content will lead to higher movable water saturation in tight sandstone gas reservoirs. These results provide clues for identifying gas–water bearing reservoirs and evaluating and predicting the water production characteristics in gas wells in tight sandstone gas reservoirs.

Influence of Various Control Factors on Fracture Toughness and Fracture Energy of Sandstone Subjected to Liquid Nitrogen Cooling

“…Generally, TSGR have a high-water content, such as there are serious water production issues in most of the wells of the Sulige TSGR. − During LN 2 cooling, water inside the sandstone will be frozen into ice, in this process a frost force can be generated to break the pore structure of the sandstone . Thus, the water content of the sandstone cannot be ignored during the LN 2 cooling process.…”

The Microscopic Production Characteristics of CO2 Flooding AF-Ter Water Flooding for Tight Oil Sandstones Reservoirs Utilized NMR and Microscopic Visualization Apparatus

“…Due to the low oil recovery of primary depletion mining and secondary water injection development, the overall oil recovery of low-permeability tight sandstone reservoirs is significantly lower than that of conventional oil reservoirs [8,9]. Water flooding has a limited impact on the improvement of tight oil reservoir yields [10,11]. To further enhance the oil recovery of tight oil formations, petroleum researchers must identify and implement innovative strategies.…”

Microscopic characteristics of water invasion and residual gas distribution in carbonate gas reservoirs

“…Fracture‐pore gas reservoirs are the most common type of carbonate gas reservoir. For a fracture‐pore gas reservoir with edge and bottom water, the water can easily flow into the production well through the fractures, causing water channeling, lower production, and even a cessation of production, leading to a lower recovery 1‐11 . Researchers have conducted a great deal of work on the water invasion mode and invasion mechanism.…”

“…Researchers have conducted a great deal of work on the water invasion mode and invasion mechanism. The water invasion mode includes the water cone mode, vertical channeling mode, lateral invasion mode, and vertical channeling‐lateral invasion mode 1‐11 …”