Integration of microseismic and other post-fracture surveillance with production analysis: A tight gas study
Integration of microseismic and other post-fracture surveillance with production analysis: A tight gas study
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DOI：
10.1016/j.jngse.2011.03.003
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发表时间：
2011-05
影响因子：
--
通讯作者：
C. Clarkson;J. Beierle
中科院分区：
文献类型：
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作者：
C. Clarkson;J. Beierle
致密气藏的定量生产分析历来是一个挑战，因为复杂的储集层特征(例如。横向和纵向非均质性、渗透率和孔隙度的应力敏感性)，导致直井水力压裂特性(例如。多相流、电导率变化、复杂的裂缝几何形状)、操作复杂性(例如可变背压、液体装填)和数据质量(不频繁的速率或流动压力报告)。所有这些挑战都使得从生产/流动压力数据中提取储层(KhandOGIP)和水力裂缝属性(xf和裂缝导流能力)变得困难，往往导致答案不唯一。在近代史上，致密气(以及最近的页岩气)气藏的开发变得更加复杂，现在正在用水平井开采，通常使用多个水力压裂阶段进行增产，这给分析带来了更大的复杂性。流型识别是正确分析的关键，但由于此类井中可能遇到的流型数量之多，识别变得比以往任何时候都更加复杂。实例研究表明，现代压裂后监测数据，如微地震和压裂后生产测井，有助于模型识别和模型标定，这对于在致密气层中完成的水力压裂水平井的分析是至关重要的。提出了一种工作流程，即首先对(相对于水平井的)偏移直井进行水力压裂性能的估算，然后对多(横向)水力压裂水平井进行阶段性和单段性生产分析。微地震资料被纳入水平井的分析中，以1)了解诱发的水力裂缝的方向和复杂程度，2)约束从生产数据分析中对有效水力裂缝长度的解释。研究还表明，一旦完成水平井的混合阶段分析，就可以利用生产测井和示踪剂测井相结合的方法，在各阶段之间分配解释的总有效水力压裂裂缝半长。本次工作的主要贡献是提出了工作流程，强调了各种数据源的集成，以改进致密气地层中完成的多压裂水平井的产量分析。结果表明，除了工作流程外，可能还需要结合先进的生产分析方法，包括类似于经典压力瞬变分析的方法、生产类型曲线拟合和模拟，才能得出独特的分析结果。
Quantitative production analysis of tight gas reservoirs has historically been a challenge due to complex reservoir characteristics (ex. lateral and vertical heterogeneity, stress-sensitivity of permeability and porosity), induced hydraulic fracture properties in vertical wells (ex. multi-phase flow, conductivity changes, complex fracture geometries), operational complexities (ex. variable back-pressure, liquid-loading) and data quality (infrequent rate or flowing pressure reporting). All of these challenges conspire to make extraction of reservoir (khandOGIP) and hydraulic fracture properties (xfand fracture conductivity) soley from production/flowing pressure data difficult, often resulting in non-unique answers. In recent history, there has been the added complication that tight gas (and most recently shale gas) reservoirs are now being exploited with horizontal wells, often stimulated using multiple hydraulic fracture stages, which imparts greater complexity on the analysis. Flow regime identification, which is critical to the correct analysis, is more complicated than ever owing to the number of possible flow regimes encountered in such wells.A case study is presented in which it is demonstrated that modern post-fracture surveillance data, such as microseismic and post-frac production logging, aids in both model identification and model calibration, which is critical to the analysis of hydraulically-fractured horizontal wells completed in tight gas formations. A workflow is presented in which offset vertical wells (to the horizontal wells) are first analyzed to obtain estimates ofkhand hydraulic fracture properties, followed by commingled stage and single-stage production analysis of the multi- (transverse) hydraulic fracture horizontal wells. Microseismic data is incorporated into the analysis of the horizontal wells to 1) understand the orientation and degree of complexity of the induced hydraulic fractures and 2) constrain interpretations of effective hydraulic fracture lengths from production data analysis. It is also demonstrated that once the commingled stage analysis of the horizontal wells is completed, the total interpreted effective hydraulic fracture half-length may be allocated amongst the stages using a combination of production logs and tracer logs.The primary contribution of the current work is the presentation of workflows, emphasizing the integration of various data sources, to improve production analysis of multi-frac’d horizontal wells completed in tight gas formations. In addition to the workflows, it is shown that a combination of advanced production analysis approaches, including methods analogous to classic pressure transient analysis, production type-curve matching and simulation, may be necessary to arrive at a unique analysis.