The Reasonable Production Mode of Shale Gas Well with Considering Stress Sensitivity

Abstract

High-pressure deep shale gas reservoirs are usually highly stress-sensitive. When the reasonable production mode of shale gas well is built, the impact of strong stress sensitivity should be fully considered. First, this study calculated the relationship between permeability and formation pressure under different elastic modulus based on the shale lithology of Long Ma Xi formation in Sichuan Basin by testing and analysing the mechanical parameters of the rock. According to numerical simulation result, when the elastic modulus exceeds 14.0 GPa, the stress sensitivity of the matrix will slight affect the cumulative gas production of shale gas. Second, the changing relation between fracture conductivity and permeability with fracture pressure and the time of pressure acts were experimentally studied. The numerical simulation result suggested that the 30-year cumulative gas production considering the stress sensitivity was reduced by 13.5% compared with the 30-year cumulative gas production without considering the stress sensitivity. Finally, the production of different production modes under different stress sensitive characteristics was predicted using numerical simulation method. When the matrix and fractures are fixed with a same stress-sensitive curve, the initial production allocation will not significantly impact the cumulative gas production. When the fractured fractures are subjected to a varying stress sensitive curve, the lower production allocation will result in higher post-production and cumulative gas production.

Environmental Friendliness and High Performance of Multifunctional Tween 80/ZnO-Nanoparticles-Added Water-Based Drilling Fluid: An Experimental Approach

“…Shale oil production climbed to 2.81 billion barrels which represents approximately 63% of overall US crude oil production in 2019 . The demand of energy is continuously increasing; therefore, exploration and production companies are seeking novel ways to exploit the potential of unconventional hydrocarbons, such as heavy oil, gas hydrate deposit, , oil sand, coal bed methane, , tight gas-sand, − and oil and gas shales. , However, smectite/montmorillonite-rich shale is more susceptible to water in terms of its swelling, and it may raise problems of wellbore instability when drilling into the shale. − Notably, shale instability accounts for 90% of all global wellbore drilling problems. , Swelling in high montmorillonite content shale and environmental rehabilitation of drilling location are two major concerns that need to be addressed. , …”

Numerical simulation study on the mechanical behavior of shale core and reservoir rock mass

“…Shen et al 9 found that the permeability sensitivity of shale fractures under stress was very strong, and the exponential relationship better described the pressure dependency of the permeability for the tested shale samples. For high‐pressure deep shale gas reservoirs, which ware usually highly stress‐sensitive, the impact of strong stress sensitivity should be fully considered 10 . These studies on stress sensitivity are abundant, but the results are inconsistent.…”

A Multiphase Wellbore Flow Model for Sour Gas “Kicks”

“…The highest CO 2 content in the center of Tarim Basin in China reaches 67% [2], and the H 2 S content of gas fields at South Texas in the U.S. is up to 98%. Sour gas reservoirs are generally located in deep marine carbonate formation and are characterized by high temperature and high pressure (HTHP), complex formation pressure system and narrow mud density window, which frequently cause complicated accidents during drilling operations [3]. Sour gas could easily invade into wellbore and cause kicks and blowouts while drilling sour gas reservoirs especially with high H 2 S or CO 2 content.…”