Efficient Remaining Oil Production Enhancement Technology in Daqing Oilfield Based on Integrated Application of Multiple Technologies

Daqing Oilfield has entered a late development stage, characterized by a high recovery rate and high water cut. At this stage, it faces multiple challenges, including a highly scattered distribution of remaining oil reserves, severe water flooding, an increasing proportion of casing-damaged wells, and elevated drilling risks under conditions of continuous injection and operations without depressurization. To address these challenges, a full-chain production enhancement technology was developed based on the integrated application of three key technologies, including ultra-short radius horizontal well technology, managed pressure drilling for adjustment wells, and water control and casing damage prevention technology. The integrated technology system includes targeted tapping of remaining oil potential, low-cost infill and adjustment operations, dynamic suppression of water channeling, and long-term casing damage control. Ultra-short radius horizontal well technology achieved sidetracking from existing wells through geology-engineering integration, measurement and control while drilling, and the use of high-build-rate flexible drilling tools, etc. The approach accurately connected dispersed remaining oil-enriched zones, expanded the drainage area, and significantly increased single-well production. The technology was also applied to restore the productivity of casing-damaged wells. The managed pressure drilling technology for adjustment wells was based on accurate formation pressure prediction models and employed a refined managed pressure drilling system. It enabled precise and automated control of wellbore pressure under conditions of simultaneous injection, production, and drilling, thus ensuring drilling safety and cementing quality without shut-in or with only limited shut-in. The water control and casing damage prevention technology included full-seal cementing surface control, long rubber-element packer technology, self-pressurizing dual-packer cementing for high-pressure formations, and double-layer casing with hollow-structure technology. These measures effectively suppressed fluid overflow from high-pressure formations, improved cementing bond quality, and mitigated the direct impact of formation creep on casing by providing a buffering clearance, thus preventing and controlling casing damage. The integrated application of multiple remaining oil production enhancement technologies was implemented in 117 wells with formation pressure coefficients ranging from 1.8 to 2.0 in Daqing Oilfield, achieving safe drilling and completion without shut-in or with limited shut-in. Cementing quality was significantly improved, with the proportion of high-quality cementing increasing by 35.8 percentage points. As a result, the average casing damage rate decreased by 9 percentage points year-on-year, the service life of oil wells was extended, and cumulative incremental oil production reached 1.125××10⁴ t. The proposed method provides robust technical support for maintaining stable production and improving operational efficiency in Daqing Oilfield, as well as other mature oilfields with high water cut.