Strategy and practice of profitable development of low-grade reserves and its practice in Wuliyasitai Oil Field, Erlian Basin

doi:10.3969/j.issn.1672-7703.2026.01.015

Abstract

Abstract: As one of the typical low porosity and ultra-low permeability oilfields in Erlian Basin, the development situation of Wuliyasitai Oilfield is becoming more and more serious in recent years after years of exploration and development. It is faced with the problems of weak resource replacement ability, difficult implementation of high-quality reservoirs and poor benefit of vertical well development.Therefore, based on the stock reserves area, some new technologies for profitable development of low-grade reserves are explored and formed by referring to the concept of tight oil efficiency development: (1) Accurately select the favorable zones and layers, through the analysis method of reservoir unit based on sedimentary microfacies and the meticulous analysis of development effect , the favorable reservoir distribution and reservoirs development characteristics are clarified, and the types of remaining resource reservoirs with horizontal well development potential are optimized to support the well location deployment. (2) Precise and ingenious well location designing, established the deployment principle of horizontal wells in low-grade reservoirs, and innovatively designed three horizontal well models with a deviation angle of less than 85°to ensure the dessert drilling ratio and drilling efficiency, including the models of “Drilling through thick oil layer from top to bottom” , “thin oil layer targeted drilling”, “targeted drilling in the upper and lower oil layer dessert”(longitudinal multi-layer penetrating drilling). (3) By strengthening on-site tracking while drilling and accurate evaluation after drilling, the reservoir reconstruction is transformed from the early “ large-scale long fracture reconstruction mode ” to the “close cutting volume reconstruction mode ” to improve the reservoir reconstruction effect. Based on the above technical sequence, by testing the development method of “horizontal well with inclination angle less than 85°+ high strength volume fracturing” in T21 block of Wuliyasitai Oilfield, the average single well EUR of is increased to 3 times and the initial average single well daily oil production is increased by 3 to 4 times with the drilling investment equivalent to 1.5 times of vertical well, and the development benefit is greatly improved. The newly formulated strategies for the economic development of low-grade reserves have effectively promoted the rapid transformation of low-grade resources in Wuliyasitai Oilfield and other low-grade resources in Erlian Basin. The phased achievements are notable, and the approach exhibits considerable potential for popularization and application in relevant fields.

Key words: Erlian Basin, Wuliyasitai oil field, low-grade reserves, profitable development, horizontal well

CLC Number:

Tang Xiaoling, Wu Yuewei, Yang Jingdong, Gao Lan, Ma Limin, Wu Wanglin, Pan Yongli, Chao Xianqiu. Strategy and practice of profitable development of low-grade reserves and its practice in Wuliyasitai Oil Field, Erlian Basin[J]. China Petroleum Exploration, 2026, 31(1): 205-216.

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