Stable Production Technology for Horizontal Well Development in Shallow Water Delta Oilfield of Bohai Bay, China

摘要

BZ Oilfield is a medium-sized oilfield with shallow delta facies deposits in Bohai Bay of China, compared with fluvial and delta facies oilfields, there is no mature experience for reference of reservoir configuration, well pattern arrangement and development model in offshore oilfields in China. In view of the difficulty in describing the reservoir configuration of shallow water delta, the single distributary sand dam in shallow water delta is characterized by well-seismic combination and multi-attribute constraints. The mathematical mechanism model of pinch-out position of sand body is established, fine characterization of BZ shallow water delta reservoir is put forward. The horizontal well pattern arrangement type for shallow water delta reservoir is proposed and the method of well pattern optimization based on vertical displacement theory is put forward. A method of inversion of reservoir connectivity using production dynamic data by numerical well testing is proposed and a new method for optimizing water injection rate in water injection wells is proposed aiming at the difficulty of recognizing injection-production connectivity of shallow water delta reservoirs. The fine configuration of BZ shallow water delta reservoir based on distributary sand dam is proposed, which guides the recognition of remaining oil distribution law. By deploying adjustment wells, the water flooding coincidence degree of actual drilling is 86% compared with that of pre-drilling prediction, which indicates that the research results of reservoir configuration can effectively guide the understanding of oilfield geology. Through the theoretical well arrangement type of vertical displacement of single sand body in horizontal wells of shallow water delta reservoir, a high water flooding recovery rate of 35% is achieved in primary well pattern. The connectivity coefficients of injection-production boundary of shallow water delta reservoir configuration are calculated, and the water injection distribution coefficients are obtained by normalizing the directional coefficients. This paper presents a configuration method based on multi-attribute fusion under the constraints of sedimentary process. In this paper, a shallow water delta reservoir configuration method based on multi-attribute fusion constrained by sedimentary process is proposed, and the injection-production connectivity coefficient and injection well distribution coefficient of the configuration boundary are calculated.