Selective injection equipment (SIE) has been used In the Rangely Weber Sand Unit to improve the vertical conformance of both a mature waterflood and a full-scale CO2 flood. The Ershaghi technique of waterflood reserves estimation shows that SIE has improved ultimate waterflood recovery by approximately 6.6% of the original oil in place. Scoping economics, applied to historical production data, show that this additional oil recovery is profitable. profitable. The application of SIE to the Rangely CO2 Project is reviewed, including information on Project is reviewed, including information on corrosion, SIE run life, and the technique of "blanking" high-permeability thief zones to reduce Inefficient cycling of CO2. A discussion Is presented on SIE optimization through the use of injection profile data, permeability information, production and permeability information, production and injection data, and reservoir simulation. The paper concludes by addressing the feasibility paper concludes by addressing the feasibility of applying SIE to other oil fields with similar reservoir characteristics.
Obtaining good vertical conformance is important to the success of any secondary or tertiary flood. This is particularly true in the Rangely Weber Sand Unit (RWSU), where six major producing horizons contain recoverable oil. In order to effectively flood all of these major intervals, 173 out of the 328 active injection wells in the Unit are equipped with some form of selective injection equipment (SIE). The SIE used in Rangely consists of several packers and mandrels placed vertically across the productive Weber interval (see Figure 1).