Downhole Tiltmeter Fracture Mapping: Finally Measuring Hydraulic Fracture Dimensions

Abstract

Abstract This paper introduces a new fracture diagnostic technology that allows economic mapping of hydraulic fracture dimensions. The downhole tiltmeter fracture mapping technology requires the use of an offset wellbore(s) for running wireline-conveyed downhole tiltmeter arrays. For the first time, hydraulic fracture dimensions including growth during pumping can be measured at a relatively modest cost. In addition to providing fracture diagnostic data (fracture height, width and length), this new capability allows enhanced utilization of hydraulic fracture models because model predictions can be "calibrated" with in-situ observations of fracture growth. The concept is quite simple: creating a hydraulic fracture involves parting the rock and deforming the reservoir. Downhole tiltmeter mapping involves measuring the fracture-induced deformation in a nearby offset well(s) and solving the geophysical inverse problem to obtain the created fracture dimensions. The technology follows the same principles as surface tiltmeter mapping, but the different array geometry and placement make it very sensitive to fracture dimensions and less sensitive to fracture orientation - just the reverse of surface tiltmeter mapping. This paper will explain the fundamental concepts, the implementation strategy (wireline conveyed tiltmeter arrays, data acquisition, processing, and modeling), and three field case studies of measured hydraulic fracture growth.