Experimental Evaluation of Unconventional Reservoir Sample Properties Using Rate- and Pressure-Transient Analysis Methods

在加拿大，含有石油和富液气的超低渗透率（“非常规”）储层（URs）是碳氢化合物生产的关键来源。多裂缝水平威尔斯（MFHWs）提供了从URs中回收油、气和凝析油的技术。这些URs的早期开发集中在一次采油（压力衰竭）策略的使用上，但该行业目前正在评估使用循环气体（溶剂）注入提高石油采收率（EOR）的潜力。然而，使用MFHW的开采过程的优化需要估计影响烃类生产和溶剂注入的关键储层和水力压裂特性。因此，了解如何推进储层/水力压裂表征方法对于通过一次采油和强化采油工艺实现URs的可持续发展至关重要。 虽然可以在实验室中使用岩心样品确定储层性质，但是实验条件通常不能再现在现场生产MFHW的条件，并且不能以相同的方式分析结果。因此，实验室测试结果是否能提供应用于实地数据的关键输入模型，值得怀疑。 最近，克拉克森研究小组开发了一种新的实验方法和分析程序，以更好地再现MFHWs在田间生产的条件。新的革命性的实验方法，被称为RTAPK '，使用相同的生产数据分析方法，适用于MFHW。对岩心塞样品的产气量进行分析，可以在原地应力条件下确定渗透率和孔隙体积（以及孔隙度）的关键储层特性。一项概念验证研究表明，核心测试确实可以重现现场观察到的行为，并比传统的核心测试方法更快、更有信心地提供关键输入数据。 这一概念验证研究的成功激发了一项新的5年研究计划的启动，该计划不仅旨在使用RTAPK方法改进实验室对关键UR属性的估计，而且还评估了对非常规油藏中流体流动和储存的基本控制。这一新项目的目标是：1）扩大RTAPK装置的渗透率限值，使其更广泛地适用于加拿大URs; 2）构建一种新的RTAPK装置，用于确定URs中多相（气、油、水）流动建模的关键属性; 3）使用由此产生的RTAPK数据库来解决URs中流体流动性质的基本问题。 由于这种新的创新实验室技术的进一步发展，加拿大使用一次采油和强化采油工艺的油田开发规划将得到改进，从而更有效地开采这些关键的碳氢化合物资源。

Ultra-low permeability (“unconventional”) reservoirs (URs) that host oil and liquid-rich gas are critical sources of hydrocarbon production in Canada. Multi-fractured horizontal wells (MFHWs) have provided the technology to recover oil, gas and condensate from URs. Early development of these URs has focused on the use of primary recovery (pressure depletion) strategies, but the industry is currently evaluating the potential for enhanced oil recovery (EOR) using cyclic gas (solvent) injection. Optimization of recovery processes using MFHWs, however, requires estimation of key reservoir and hydraulic fracture properties that affect hydrocarbon production and solvent injection. Understanding how to advance reservoir/hydraulic fracture characterization methods is therefore critical for achieving sustainable development of URs through primary and enhanced recovery processes. While reservoir properties may be determined in the laboratory using core samples, the experimental conditions generally do not reproduce the conditions under which MFHWs are produced in the field, and the results are not analyzed in the same way. The usefulness of the laboratory test results for providing critical input models applied to field data are therefore in question. Recently the Clarkson research group developed a new experimental method and analysis procedure to better reproduce conditions under which MFHWs produce in the field. The new revolutionary experimental approach, referred to as RTAPK', uses the same production data analysis methods as those applied to MFHWs. Analysis of gas production from core plug samples allows the key reservoir properties of permeability and pore volume (and hence porosity) to be determined at in-situ stress conditions. A proof-of-concept' study demonstrated that core tests could indeed reproduce behaviors observed in the field, and provide key input data faster, and with more confidence, than conventional core testing methods. The success of this proof-of-concept study has inspired the initiation of a new 5-year research program aimed at not only improving laboratory-derived estimates of critical UR properties using the RTAPK method but also evaluating the fundamental controls on fluid flow and storage in unconventional reservoirs. The objectives of this new program are to 1) expand the permeability limits of the RTAPK device to make it more widely applicable to Canadian URs; 2) construct a new RTAPK device for the purpose of determining properties critical to modeling multi-phase (gas, oil, water) flow in URs and; 3) use the resulting RTAPK database to address fundamental questions about the nature of fluid flow in URs. As a result of the further development of this new, innovative laboratory technique, field development planning of Canada's URs using primary and enhanced recovery processes will be improved, leading to more efficient exploitation of these critical hydrocarbon resources.