碳酸钙晶须对CO_(2)诱导固井水泥石裂缝自愈合的影响研究  

Research on the Effect of Calcium Carbonate Whiskers on the Self-healing of Cement Stone Cracks Induced by CO_(2)

作　　者：龚鹏 程小伟[1,2] 武治强 张高寅 张春梅[1,2] GONG Peng;CHENG Xiaowei;WU Zhiqiang;ZHANG Gaoyin;ZHANG Chunmei(School of New Energy and Materials,Southwest Petroleum University,Chengdu 610500,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Southwest Petroleum University,Chengdu 610500,China;CNOOC Research Institute Co.,Ltd.,Beijing 100028,China)

机构地区：[1]西南石油大学新能源与材料学院,成都610500 [2]西南石油大学油气藏地质及开发工程国家重点实验室,成都610500 [3]中海油研究总院有限责任公司,北京100028

出　　处：《材料导报》2023年第7期67-73,共7页Materials Reports

基　　金：国家重点研发计划(2016YFB0303600);四川省区域创新合作项目(2021YFQ0045)。

摘　　要：CO_(2)的捕集、利用和封存(CCUS)井下固井水泥环的开裂损伤不可避免。本工作采用高浓度CO_(2)与碳酸钙晶须反应诱导CaCO_(3)沉积,以提高固井水泥石裂缝的自愈性能。利用抗压强度仪、X射线衍射仪(XRD)、热重分析仪(TG)、环境扫描电子显微镜(ESEM)和X射线显微计算机断层扫描(μ-CT)等测试仪器,研究碳酸钙晶须对固井水泥石自愈过程的影响。抗压强度结果显示,掺入与未掺入碳酸钙晶须水泥石在劈裂后,经过碳化自愈合反应28 d,其抗压强度均随着碳化时间的延长而提高,抗压强度的增长率分别为572%和528%。另外物相分析结果表明,随着碳化时间的延长,掺入碳酸钙晶须水泥石裂缝表面Ca(OH)_(2)的质量损失(0.58%)明显小于未掺入碳酸钙晶须的水泥石的Ca(OH)_(2)质量损失(2.68%)。ESEM结果表明,在水泥石裂缝表面,有碳化产物方解石与文石生成并沉积在裂缝处,使得水泥石裂缝自愈合。μ-CT测试结果表明,掺入碳酸钙晶须水泥石裂缝的自愈合率达到了55.24%,而未掺入碳酸钙晶须水泥石裂缝的自愈合率只有18.32%,这表明在CCUS井下,在固井水泥石中掺入碳酸钙晶须对水泥石裂缝的碳化自愈合过程有利。The cracking damage of the cement ring in CCUS downhole cementing is inevitable.In this work,high-concentration CO_(2)reacts with CaCO_(3)whiskers to induce CaCO_(3)deposition to improve the self-healing performance of cement-based material cracks.Compressive strength tes-ter,X-ray diffractometer(XRD),thermogravimetric analyzer(TG),environmental scanning electron microscope(ESEM)and X-ray micro-computed tomography(μ-CT)were used to study the influence of CaCO_(3)whiskers on the self-healing process of cement.The compressive strength results show that the compressive strength of cement mixed with CaCO_(3)whisker and without CaCO_(3)whisker after being carbonized for 28 days increases with the increase of carbonization time,and the growth rate of compressive strength are 572%and 528%,respectively.In addition,the XRD and TG results show that the mass loss and diffraction peaks of the sample Ca(OH)_(2)at the cracks of the cement gradually disappear with the increase of the carbonization time with the CaCO_(3)whisker cement.In addition,the phase analysis results show that with the prolongation of carbonation time,the mass loss of Ca(OH)_(2)on the crack surface of cement paste with calcium carbonate whiskers(0.58%)is significantly less than that of cement paste without calcium carbonate whiskers(2.68%).It shows that the addition of CaCO_(3)whiskers has a certain promotion effect on the carbonization of cement.The ESEM results show that on the surface of cement cracks,carbonized products of calcite and aragonite are formed and deposited on the cracks to make the cement cracks self-healing.The test results ofμ-CT show that the self-healing rate of cement with CaCO_(3)whisker reached 55.24%,while the self-healing rate of cement without CaCO_(3)whisker was 18.32%.This indicates that mixing CaCO_(3)whiskers into cement is beneficial to the carbonization self-healing process of cement cracks under the CCUS downhole.

关 键 词：裂缝 碳化自愈合 碳酸钙晶须 CCUS 

分 类 号：TE256[石油与天然气工程—油气井工程]