Innovative Unconventional Formation Evaluation Approach in a Tight Oil Reservoir, Xinjiang Oilfield, China

Complicated minerals, high total organic carbon (TOC) content, and thin interbeded layers aggravated the complexity of logging responses and made it very difficult to find the target zone of the tight oil reservoir in the Jimusaer depression in northwestern China. Horizontal well drilling is extremely difficult in the formation due tohigh heterogeneity and uncertain fault, it caused hundreds of millions of dollars' loss to drill one horizontal well without targeting the zone. To maximize oil production with low cost, an integrated solution is provided. First, we used an unconventional evaluation approach to integrate an elemental capture spectroscopy log with other logs to get accurate reservoir characteristics. Second, we built a 3D structural model to target the best reservoir. Third, we combined Reservoir Quality (RQ), Completion Quality (CQ), and 3D structural models to optimize the stimulation design and enhance production. With this approach, which integrates the RQ and CQ parameters into the 3D structural model, not only can we evaluate the effective porosity, saturation, minerals, fractures, TOC, and stress profile along the wellbore, but also can get a clear picture of these properties in 3D distribution so that multistage hydraulic fracturing design can be made more effectively and at lower cost. Application of this approach on several wells proved that it is an effective way for tight oil reservoir evaluation and production enhancement.