Development of a comprehensive workflow for combined analysis of flowback and post flowback production data from multifractured horizontal wells completed in gas shales

在北美，利用多分支/多裂缝水平井从致密烃资源中开采油气的技术正在迅速发展。然而，要想高效、负责、可持续地开发此类非常规能源，就需要对大规模压裂作业进行有代表性的评估。英属哥伦比亚东北部的合恩河组是非常规天然气聚集的一个例子。据估计，该地层的页岩成员中储存着高达500万亿立方英尺的天然气，使其成为北美第三大天然气聚集区。表征Horn River页岩的裂缝网络是一项具有挑战性的任务，主要是因为1)岩石是天然裂缝，因此水力压裂会产生复杂的裂缝网络；2)在压裂作业后进行返排时，会立即产生水和气。拟议的研究计划将制定一个工作流程，以分析在生产阶段不同时间尺度测量的气体和水的压力和流速。研究任务将由两名博士研究生、两名硕士研究生和一名博士后分两个平行的研究阶段进行。第一阶段将模拟天然气和压裂水的两相流动，以匹配早期返排数据。第二阶段将模拟天然气在一个复杂系统中的流动，该系统由水力裂缝、重新激活的天然裂缝和页岩基质组成，以匹配反排后的生产数据。这项研究的结果将有助于业界估计诱导裂缝的体积、长度和导流能力，从而更准确地评估压裂作业、预测天然气产量和估计天然气总储量。

Extraction of oil and gas from tight hydrocarbon resources by using multi lateral/multi fractured horizontal wells is rapidly growing in the North America. However, efficient, responsible and sustainable development of such unconventional energy resources requires representative evaluation of massive fracturing operations involved. An example of unconventional gas accumulations is the Horn River Formation in northeastern British Colombia. It is estimated that up to 500 Tcf of natural gas is stored in the shale members of this formation, making it the third largest North American natural gas accumulation.Characterizing the fracture network induced in the Horn River shales is a challenging task primarily because 1) the rock is naturally fractured and therefore hydraulic fracturing results in a complex fracture network, and 2) water and gas are immediately produced when wells are put on flowback after the fracturing operations.The proposed research program will develop a workflow to analyze pressure and flow rate of gas and water measured at different time scales of the production phase. The research tasks will be conducted by two PhD students, two MSc students, and a postdoctoral fellow in two parallel research phases. Phase 1 will simulate two-phase flow of gas and fracturing water for history matching the early-time flowback data. Phase 2 will simulate flow of gas through a complex system consisting of hydraulic fractures, reactivated natural fractures, and shale matrix for history matching post flowback production data. The outcomes of this research will help the industry to estimate the volume, length, and conductivity of induced fractures that will lead to more accurate evaluation of fracturing operations, forecast of gas production, and estimation of total gas reserve.