Testing and Analysis of Wells Producing Commingled Layers in Priobskoye Field

Abstract

This paper discusses a Downhole Flow Control (DHFC) technology and describes its application for injection and fall-off testing of commingled layered reservoirs. The Simultaneous Separate Injection (SSI) technology has been successfully applied in over 150 injection wells by the Rosneft Oil Company in the Priobskoye Oil Field. The SSI assembly is a cable tool consisting of valves, packers, and pressure transducers and provides the ability to distribute the surface injection rate into individual layers in a controlled manner. The ability to control layer injection rates is intended for effective flooding of poorinjectivity layers. The concurrent measurement of layer pressures also provides the opportunity to simultaneously test multiple layers. Currently, the SSI assembly only regulates the distribution of the layer injection rates but does not measure the bottomhole injection rates. Valves on the SSI assembly are preset at the surface based on the spinner tests to determine the injection profile. The main advantage of this technique is the drastic reduction of test time and cost to obtain estimates of individual layer properties and injectivities. This paper focuses on the use of the SSI assembly in pressure-transient testing of commingled, multi-layer reservoirs. The application of the testing technology and the analysis of measured test responses are demonstrated on examples from the Priobskoye Field. Also presented are the results of the Single-Layer Steady-State Injection Tests. These tests are useful to understand the fracture development during injection and the resulting injectivity increases. This information is used to regulate the layer injection rates with the SSI technology and the in the design of the injection and fall-off tests.