Abstract

This work is dedicated to the creation of complex methods of determining reservoir properties in injection wells with injection-induced fractures by production logging tests (PLT) and well testing.

During exploitation, injection wells are known to create uncontrolled fractures so called injection-induced fractures. They appear when the injection pressure exceeds formation tensile strength. They can spread both in height and length, depending on the injection rate.

The risks of fractures inducing during work are especially great in tight formations. They influence oil field development negatively because their growth in height can connect additional layers that change the distribution of water injection in layers.

Complex analysis of PLT and well testing during step-rate injection tests and shut in provides the opportunity not only to determine fracture properties, but also to estimate parameters of layers connected by injection-induced fracture. Series of different injection pressure tests and a fall-off are suggested to perform this task. Suggested interpretation method is based on the fact, that the size of fracture changes with different injection pressure, connecting more or less layers. Joint analysis of well tests and PLTs helps to diagnose and estimate the number of these changes.

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