蒙古林砾岩油藏火驱现场试验及初期见效特征

Field test and initial response characteristics of fire flooding in Menggulin conglomerate reservoir

刘莎莎 闫暄崎 游靖 谢刚 穆化巍 王冠 杜金秀 戴坤秀

LIU Shasha YAN Xuanqi YOU Jing XIE Gang MU Huawei WANG Guan DU Jinxiu DAI Kunxiu

中国石油华北油田公司工程技术研究院 中国石油华北油田公司开发部 西南石油大学

Research Institute of Engineering Technology, PetroChina Huabei Oilfield Company, Renqiu 062550, Hebei, China Development Department, PetroChina Huabei Oilfield Company, Renqiu 062550, Hebei, China Southwest Petroleum University, Chengdu 610599, Sichuan, China

蒙古林砾岩油藏为注水开发普通稠油油藏，采取过多种油藏治理措施，目前已进入特高含水期，依靠水驱进一步提高采收率的潜力较小。为改善开发效果，开展了火驱现场试验，与国内其他火驱成功区块对比，该区块原油黏度、孔渗相对偏低，油层厚度较大，对工艺技术要求较高。针对目标区块油藏特点对火驱注气、点火工艺进行了优化，将常用的四阶注气改为三阶注气，四阶逐级升温点火改为一阶升温点火，油管注气时间由3 d缩短为1~2 h，点火19 h后点火器温度即上升到400 ℃，减少注气时间的同时提升了点火期间温度上升速度，实现安全点火。点火3个月后油井即初步见效，截至2023年5月，日产油增幅230.5%，目前仍在持续上升，综合含水率下降16.5%。与其他火驱区块相比，呈现出见效时间早，见效速度快的特征。见效初期产气以氮气为主，氧气及二氧化碳含量较低；产出原油改质明显，饱和烃含量升高，重质组分含量呈下降趋势，以上认识对同类油藏开展火驱技术具有借鉴意义。

The Menggulin conglomerate reservoir is an ordinary heavy oil reservoir undergoing water flooding development. Various stimulation measures have been implemented in this reservoir, and it has now entered a high-water-cut period, showing limited potential in further increasing the recovery rate through water flooding. In order to improve the development efficiency, a field test of fire flooding was conducted. In comparison with other successful fire flooding projects in China, this block is relatively low in crude oil viscosity, porosity, and permeability, while thick in oil layer, which poses high challenges on technological processes. Therefore, based on the characteristics of an ordinary heavy oil reservoir, the fire flooding gas injection and ignition process were optimized. The commonly used four-stage gas injection process was replaced by a three-stage gas injection process, and the four-stage gradual heating ignition was simplified to one-stage heating ignition. As a result, the gas injection duration of the tubing was shortened from 3 d to 1–2 h, and the igniter temperature rose to 400 ℃ after 19 hours of ignition. This reduced the gas injection duration of the tubing and increased the temperature rise rate during ignition, achieving safe ignition. Within three months after ignition, the oil well showed initial positive results. As of May 2023, the daily oil production had increased by 230.5%, and it is still steadily increasing, accompanied by a 16.5% decrease in overall water cut. In comparison with other fire flooding blocks, this one exhibited early and rapid response. Additionally, during the initial production stage, N was the main component of the produced gas, while O and CO were relatively low. The produced crude oil also showed significant improvement, with increased saturation hydrocarbon content and decreased heavy components. These findings provide valuable insights for implementing fire flooding in similar reservoirs.

10.13639/j.odpt.202212016