摘要
苏里格气田属于鄂尔多斯盆地典型致密砂岩气田,受储层致密、强非均质性、气水关系复杂以及原始地层压力低等因素影响,目前面临天然气储量动用规律不清楚、提高采收率方向不明确等关键瓶颈。为解决这一难题,选用苏里格气田盒8段主力储层岩心,通过建立一套逐级降压开采方式物理模拟实验方法和流程,开展了不同生产压差下逐级降压衰竭开采实验,揭示了储层压力、供气能力以及储量动用等关键指标全生命周期变化规律,明确了储量充分动用的临界地层压力,为探索提高采收率新方法奠定了理论依据。研究结果表明:①含水致密砂岩气藏储层压力、供气能力以及储量动用在不同生产阶段的变化特征差异显著,最终采收率随生产压差增大而降低;②在储层压力大于等于15MPa时,生产压差越大则储层供气能力越强,边界压力可逐级下降至井底压力,储量动用充分;③随储层压力下降至15MPa以后,储层供气能力降低,边界压力下降缓慢且不能下降至井底压力,随储层压力进一步下降其差异越明显,表明该阶段近井区和远井区储量动用存在差异,远井区储量难以得到充分动用。结论认为,对于致密含水砂岩气藏,实现储量有效动用新方向为除采用水平井部署+密切割改造技术外,应大胆探索探索补充地层能量新方法,以确保气藏维持在较高地层压力下以合理生产压差开采,进而保障气藏产能和高采收率。
Sulige Gas Field is a typical tight sandstone gas field in the Ordos Basin. Under the influence of tight reservoir, strong heterogeneity, complex gas-water relationship, low original formation pressure and other factors, it is currently faced with some key bottlenecks, such as unclear reserve production law and undefined EOR direction. In order to solve these problems, this paper selects the cores of the main reservoir(i.e., the 8^(th) Member of Shihezi Formation) in Sulige Gas Field as the research object and establishes a set of physical simulation experiment method and process of step-by-step depressurization production mode to carry out the experiment of stepby-step depressurization and depletion production under different production pressure differences. The experiment reveals the life cycle variation law of key indicators such as reservoir pressure, gas supply capacity and reserve production, and determines the critical formation pressure for the full production of reserves, so as to lay a theoretical foundation for exploring new EOR methods. And the following research results are obtained. First, as for water-bearing tight sandstone gas reservoirs, the variation characteristics of reservoir pressure,gas supply capacity and reserve production are significantly different in different production stages, and the ultimate recovery factor decreases with the increase of production pressure difference. Second, when the reservoir pressure is higher than or equal to 15 MPa, the larger the production pressure difference is, the stronger the gas supply capacity of the reservoir is and the boundary pressure can drop step by step to the bottom hole pressure, so that the reserves can be fully produced. Third, after the reservoir pressure drops to 15 MPa,the gas supply capacity of the reservoir decreases, and the boundary pressure drops slowly and cannot drop to the bottom hole pressure.And with the further decrease of the reservoir pressure, the difference becomes more obvious. This indicates that there is a difference in the reserve production between the area near the wellbore and that far from the wellbore, and the reserves in the area far from the wellbore are difficult to be fully produce. In conclusion, the new direction to effectively produce the reserves of water-bearing tight sandstone gas reservoirs is to explore new methods to supplement formation energy, besides horizontal well + dense cutting stimulation technology,so as to ensure the production of gas reservoirs at reasonable production pressure difference under higher reservoir pressure and consequently guarantee high gas reservoir productivity and a high recovery factor.
作者
李进步
王继平
李娅
胡勇
谢坤
LI Jinbu;WANG Jiping;LI Ya;HU Yong;XIE Kun(PetroChina Changqing Oilfield Company,Xi'an,Shaanxi 710018,China;National Engineering Laboratory of Low-Permeability Oil&Gas Exploration and Development,Xi'an,Shaanxi 710018,China;PetroChina Research Institute of Petroleum Exploration&Development,Beijing 100083,China;Northeast Petroleum University,Daqing,Heilongjiang 163318,China)
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2022年第1期125-132,共8页
Natural Gas Industry
基金
国家科技重大专项“鄂尔多斯盆地大型低渗透岩性地层油气藏开发示范工程”(编号:2016ZX05050)
中国石油天然气股份有限公司重大科技专项“长庆气田稳产及提高采收率技术研究”(编号:2016E-0509)。
关键词
苏里格气田
致密含水砂岩气藏
气水关系
逐级降压
衰竭开采
动用规律
提高采收率
实验研究
Sulige Gas Field
Water-bearing tight sandstone gas reservoir
Gas-water relationship
Step-by-step depressurization
Depletion production
Production law
EOR
Experimental study
