摘要
裂缝性气藏在我国油气资源中具有重要地位,其试井分析对储层评价和气藏开发具有不可或缺的作用。为了解决传统双重孔隙介质模型对天然裂缝表征不精确的难题,基于蒙特卡罗随机模拟方法和离散裂缝模型,表征了复杂分布的天然裂缝,构建了考虑离散裂缝和渗透率非均质性的径向复合裂缝性气藏数值试井模型(DFM-NM),绘制了不同参数下裂缝性气藏气井试井曲线图版,形成了解析试井初拟合、离散裂缝细拟合的试井分析方法,并开展了实例应用分析。研究结果表明:(1)裂缝性气藏不稳定流动阶段包括井筒储集和表皮效应阶段、内区裂缝影响阶段、内区径向流阶段、外区裂缝影响阶段和边界控制流阶段;(2)基于地质条件约束下的离散裂缝模型能较好表征复杂、非均质裂缝性气藏,克服了常规双重孔隙介质模型的缺点;(3)裂缝数目越多、裂缝平均长度越长,压力导数曲线下凹的幅度越大,内区裂缝参数对试井曲线形态的影响更大。结论认为,所建立的裂缝性气藏数值试井模型及粗细分步拟合方法适用于塔里木盆地裂缝性气藏,能更准确有效地评价储层、反演裂缝参数。研究成果具有良好的应用前景,可为裂缝性气藏参数反演和开发方案优化提供理论支撑,有助于我国复杂油气资源的科学开发。
Fractured gas reservoirs play an important role in the complex oil and gas resources in China, and their well testing analysis is irreplaceable for reservoir evaluation and gas reservoir development. The traditional dual-porosity model cannot accurately characterize natural fractures. To address this difficulty, this paper characterizes the complex-distribution natural fractures based on the Monte Carlo stochastic simulation method and the discrete fracture model. A numerical well testing model considering discrete fractures and permeability heterogeneity for radially complex fractured gas reservoirs(DFM-NM) is constructed. Typical gas well testing curves in fractured gas reservoirs with different parameters are plotted, and a well testing analysis method with coarse fitting of analytical well testing and fine fitting of discrete fractures is developed. In addition, the model is practically applied and analyzed. And the following research results are obtained. First, the transient period of fractured gas reservoirs is divided into wellbore storage and skin effect stage,inner-zone fracture influence stage, inner-zone radial flow stage, outer-zone fracture influence stage, and boundary dominated flow stage. Second, the stochastic discrete fracture model under the constraint of geological conditions can better characterize complex and heterogeneous fractured gas reservoirs and overcome the difficulty of conventional dual-porosity model in effective characterization.Third, the greater the number and average length of fractures, the larger the concave amplitude of the pressure derivative curve, and the greater the influence of inner-zone fracture parameters on the shape of well test curves. In conclusion, the proposed numerical well testing model and the coarse–fine staged fitting method for fractured gas reservoirs are applicable to the fractured gas reservoirs in the Tarim Basin and can evaluate reservoirs and invert fracture parameters accurately and effectively. The research results have promising application prospect, which can provide theoretical support for parameter inversion and development scheme optimization of fractured gas reservoirs and help the scientific development of complex oil and gas resources in China.
作者
陈志明
张绍琦
周彪
廖新维
Wei YU
CHEN Zhiming;ZHANG Shaoqi;ZHOU Biao;LIAO Xinwei;YU Wei(State Key Laboratory of Petroleum Resources and Prospecting//China University of Petroleum-Beijing,Beijing 102249,China;University of Texas at Austin,Texas 78712,USA)
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2023年第2期77-86,共10页
Natural Gas Industry
基金
国家自然科学基金面上项目“基于智能数值试井的页岩油压后井间干扰参数评价”(编号:52274046)、“基于试井理论和数据驱动的页岩油藏三维裂缝网络参数智能反演”(编号:52074322)。
关键词
非均质裂缝性气藏
离散裂缝模型
蒙特卡罗模拟
径向分区
试井分析
数值试井新模型
塔里木盆地
Heterogeneous fractured gas reservoir
Discrete fracture model
Monte Carlo simulation
Radial zoning
Well testing analysis
New numerical well test model
Tarim Basin
