On the gas factor change in the process of Arlanskoye field development

UDK: 622.276.346.2

Key words: oil, gas factor, gas-oil ratio, residual gas-oil ratio, dissolved gas, casing-head gas, bubble point pressure

Authors: R.N. Imashev, V.N. Fedorov (BashNIPIneft LLC, RF, Ufa), A.M. Zaripov (Bashneft-Dobycha LLC, Oil and Gas Production Department Arlanneft, RF, Neftekamsk)

Based on the field research of Arlanskoye field it is shown that current gas factors of the main development objects are less than initial reservoir gas-oil ratios. With reference to the field and laboratory investigations of other authors, we adduced the main causes of gas factor loss in process of Arlanskoye field development. The main causes of gas factor loss at Arlanskoye field are the maintenance of production wells with bottomhole pressure below the bubble-point pressure and move some of gas oil component to download and bottom water at their contact. For example, total producing water oil ratio of the one development object amounts to 9.1 t/t. Today we cannot definitely say which of the above reasons have the most value in the process of reducing the reservoir gas-oil ratio. The systematic monitoring of the gas factor on the basis of instrumental measurements in wells throughout the period of Arlanskoye field development was not made. Therefore, we don’t know in time gas-oil ratio dynamics. Also, we note that it necessary to conduct the control of the gas factor on the core network of weels for indirect estimation of current oil reservoir gas content, as on date, the Arlanskoye field has no conditions for the selection of representative samples of deep oil. The reasons for the lack of conditions for the selection of deep oil samples are high water cut wells production, operation of wells with bottomhole pressure below the bubble point pressure.
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