Research and Field Application of the Second & Tertiary Combined Chemical Flooding Technology in the Multi-Layer Sandstone Reservoir on the Period of High Water Content and High Dispersion

The C15 block in Huabei Oilfield is characterized by complex structure and multiple oil-bearing intervals. After more than 40 years of development and adjustment, it has entered the period of high water content and high dispersion with low speed and low efficiency. In order to further increase oil recovery and improve development results, the second & tertiary combined chemical flooding technology is initiated for the C15–141 well area of C15 block. In the transition from water flooding to chemical flooding in the “second & tertiary combination” exploration stage, remaining oil description technology, well location optimization deployment technology and water flooding front regulation technology are improved according to the reservoir characteristics. The formulation of heterogeneous compound oil flooding system in high temperature reservoir was innovatively developed. The EOR project is applied, as the first candidate, in January 2022, on the C15 block and achieved great success. The injecting pressure rose 5 MPa. The injection profile and production profile were modulated, and the water driving degree was increased by 3.4%.The oil rate of field pilot rose to 57.1 t/d from 26.5t/d, and The water cut decreased by 10.5%. By March 2023, 7.77% of the project design injection volume has been completed and the project has increased oil output by 11.6 thousand tons. The preliminary good effect of the Second & Tertiary Recovery Combination Reservoirs under Chemical Flooding technology in C15 block will play a good supporting role in the application of the reservoir with high water cut and high dispersion of Huabei oilfield.