Accumulation conditions, key technologies for exploration and development of heavy oil in Huanxiling oilfield, Liaohe depression

Located in the southern section of the western slope of the Western sag in Liaohe depression, the Huanxiling oilfield has excellent source-reservoir-caprock combination conditions and has developed the composite drape trap belt of tilting fault block and nine trap types. The high-quality source-reservoir-caprock conditions ensure large-scale hydrocarbon accumulation in the Huanxiling area, which has good exploration potential. The slope structure is the target region for hydrocarbon migration and accumulation in the Huanxiling oilfield. The analysis of fluid inclusions indicates multiple periods of hydrocarbon charging. The main accumulation periods are the deposition periods of the Member 3 of Shahejie Formation and the Dongying Formation. Based on the theory of composite oil and gas accumulation, various types of light oil and heavy oil reservoirs have been discovered in the Huanxiling area, and the oil and gas reserves reaches 5×108t. According to the characteristics of oil reservoirs such as large burial span, multiple oil-bearing strata, severe heterogeneity, and varied types of oil in the oilfield, multiple batches of merging processing and interpretation technologies of seismic data and inversion technologies of thin reservoirs based on geological models have been developed in the preliminary exploration stage, thus improving the accuracy of reservoir interpretation. In the development stage, this study has developed the physical simulation technology of steam drive of heavy oil, the fine description technology of thermally recovered heavy oil reservoirs, the steam stimulation technology of ordinary heavy oil, the steam drive technology of middle-deep heavy oil. Supporting technologies such as separate injection, selective injection, sand control, and lifting of heavy oil have been completed, and the crude oil recovery has been improved, thus providing a technical support for the efficient exploration and development of the Huanxiling oilfield. © 2021, Editorial Office of ACTA PETROLEI SINICA. All right reserved.