Xinjiang Petroleum Geology ›› 2022, Vol. 43 ›› Issue (4): 404-409.doi: 10.7657/XJPG20220404

• OIL AND GAS EXPLORATION • Previous Articles     Next Articles

Genesis of Calcareous Sandy Conglomerate of Baikouquan Formation in Well XIA72 Fault Block, Mabei Oilfield

WU Shunwei1(), XIA Xueling2(), ZHU Shijie1   

  1. 1. Research Institute of Exploration and Development, Xinjiang Oilfield Company, PetroChina, Karamay, Xinjiang 834000, China
    2. Beijing Sunshine Geo-Tech Co. Ltd., Beijing 100192, China
  • Received:2021-11-18 Revised:2022-01-31 Online:2022-08-01 Published:2022-07-26
  • Contact: XIA Xueling E-mail:wshunwei@petrochina.com.cn;xxl6104110@163.com

Abstract:

Calcareous sandy conglomerate was encountered in multiple wells in the oil layers of the Lower Triassic Baikouquan formation in Well XIA72 fault block, MA131 well block, Mabei oilfield, gas logging result shows that the total hydrocarbon content is low, and the physical and oil-bearing properties of reservoirs are poor, which affects the oil layer drilling rate and the later horizontal well deployment. According to the core, logging and seismic data, the genesis, identification and distribution of calcareous sandy conglomerate in the Baikouquan formation, Well XIA72 fault block were discussed. The results show that the calcareous cement in the calcareous sandy conglomerate in the study area was formed in the late diagenetic stage, and it has a destructive effect on the reservoir. The distribution of the calcareous sandy conglomerate is mainly controlled by sedimentary facies and early faults, with the logging responses characterized by high resistivity, high density and low interval transit time, which are reflected as “bright spots” on the seismic section. The distribution of the calcareous sandy conglomerate in the study area was predicted by means of the maximum likelihood system, root mean square amplitude and maximum amplitude, among which the last one can accurately reflect the distribution. The calcareous sandy conglomerate in the study area is found in massive distribution controlled by sedimentary microfacies and NW trending banded distribution controlled by faults. According to the prediction results, the deployment of 27 horizontal wells was optimized.

Key words: Junggar basin, Mahu sag, Mabei oilfield, Baikouquan formation, calcareous sandy conglomerate, logging response, seismic attribute

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