高温干烧和水湿环境对水泥石结构性能的影响

Influence of high-temperature dry combustion and water wet environment on the structure and property of set cement

薛国庆 刘旭 汤明光 于成超 罗佼 付强

XUE Guoqing LIU Xu TANG Mingguang YU Chengchao LUO Jiao FU Qiang

中海石油(中国)有限公司海南分公司 西南石油大学石油与天然气工程学院

CNOOC China Limited Hainan Company, Haikou 570300, Hainan, China Petroleum Engineering School, Southwest Petroleum University, Chengdu 610500, Sichuan, China

为了更真实评价稠油热采井中交变超高温对水泥石力学性能及微观结构的影响，基于其在井下所处的实际环境，设计了一套超高温水湿模拟养护装置及方法，并据此研究了水泥石在干烧和水湿环境下抗压强度的变化规律。同时，利用XRD、TG、氮吸附及SEM技术探明了不同养护环境对水泥石物相组成、化学结构、孔隙结构及微观形貌的影响。实验结果表明：交变超高温养护7轮次后，水泥石在干烧环境下的抗压强度由28.7 MPa降至23.62 MPa，降幅为17.7%；而水湿环境则由29.54 MPa降至27.68 MPa，降幅为6.3%，且与干烧环境相比，抗压强度提高了14.67%；水泥石在水湿环境下水化产物含量高，孔径及孔隙率低，并且整体结构致密。研究结果可为稠油热采水泥石的性能评价提供技术支撑和理论指导，对加大稠油资源的安全、高效开发具有重要意义。

In order to evaluate the influence of alternating ultra-high temperature on the mechanical property and microstructure of set cement in a heavy oil thermal recovery well more accurately, this paper designed a set of ultra-high temperature water wet simulation curing device and method based on the actual downhole environment of set cement. And based on this, the change laws of the compression strength of set cement under dry combustion environment and water wet environment were studied. In addition, the influence of different curing environments on the physical composition, chemical structure, pore structure and micromorphology were explored by means of XRD, TG, nitrogen adsorption and SEM technology. It is experimentally indicated that after set cement is cured 7 rounds under alternating ultra-high temperature, its compression strength under the dry combustion environment decreases by 17.7% from 28.7 MPa to 23.62 MPa; but in the water wet environment, it decreases by 6.3% from 29.54 MPa to 27.68 MPa, which is 14.67% higher than the value in the dry combustion environment. Furthermore, the set cement in the water wet environment has high hydration product content, small pore diameter, low porosity and compact overall structure. The research results can provide technical support and theoretical guidance for the performance evaluation of set cement in heavy oil thermal recovery wells and is of great significance to enhance the safe and efficient development of heavy oil resources.

10.13639/j.odpt.2021.03.007