Compound Sand Architecture of Meandering Reservoir and its Application in Offshore Q Oil Field, Bohai Bay Basin, Eastern China

Abstract

With the high risk and high cost of offshore oil and gas field development, fewer wells are usually used to try to produce more oil and gas. However the complex geologic background of fluvial facies are facing the problem that the reservoir is very difficult to be characterized and predicted as channels always migrate and cut the foregoing formation rapidly. Aiming at the problem, the compound sand architecture is debated to meet with the need of offshore fluvial reservoir development strategy on the base of the idea that most of the fluvial sand bodies are not single sand body. The so-called compound sand architecture is therefore put forward, which means a set of sand complexes consisted by some specific genetic association in some a geologic time unit, according to the study of core, logging data, modern sedimentology and outcrop. The compound sand bodies may include compound channel belts, compound point bars, point bars and lateral accretion bodies. The low level compound sand body are consisted by several whole and incomplete high level compound sand bodies, in which compound point bar sand bodies are formed by the channels’ migrating and swinging. Its inner point bars repeat the progress “sediment-invasion-sediment” and every swinging of channel forms one compound point bar. Every hierarchy has its typical characteristics, which is used to determine remaining oil and well locations. Therefore long well distance development strategy can be made up properly. Also a bridge between the fine sedimentary unit and seismic data is built up, which makes it possible to solve the reservoir stratigraphic correlation problem that resulted by long well distances of the offshore oil field. In the method seismic data are the main tool, which is carefully used to study the stratigraphic frames and fine sedimentary facies together with the support of well cores and logging data. At present the compound sand architecture technique has been successfully applied in the production of meandering reservoir in Q oil field, Bohai Bay basin, eastern China.

AAPG Datapages/Search and Discovery Article #90332 © 2018 AAPG International Conference and Exhibition, Cape Town, South Africa, November 4-11, 2018