微裂缝模拟新方法及承压封堵能力评价实验研究及应用

Experimental Research and Application of a New Method for Microfracture Simulation and Evaluation of Pressure Sealing Capacity

目前来说,国内外对于提高地层承压能力的评价通常采用各种人造裂缝的方法,如人造岩心、砂盘、模具等,或采用各类堵漏评价方法用于提高地层承压能力评价。评价的准确性依赖于对地层裂缝的复原程度,本文借助3D打印技术,通过对地层裂缝展布情况的分析对应地设计3D打印岩心,并以“应力笼”理论为基础,设计一套新型的承压评价装置对钻井液提高地层承压能力进行评价。通过对封堵层失稳因素的研究,在实验室中评价优选出了XNCY系列刚性材料,并明确其最优级配关系,形成致密的封堵层而提高地层承压能力,室内实验结果表明,该配方能够在基浆基础上承压能力达7MPa。

At present,the evaluation of improving the pressure bearing capacity of the formation at home and abroad usually adopts various artificial fracture methods,such as artificial cores,sand disks,molds,etc.,or adopts various plugging evaluation methods to improve the pressure capacity of the formation.The accuracy of the evaluation depends on the degree of restoration of formation fractures,and this paper uses 3D printing technology to design 3D printed cores corresponding to the analysis of formation fracture distribution,and designs a new pressure-bearing evaluation device based on the"stress cage"theory to evaluate the pressure bearing capacity of drilling fluid.Through the study of the instability factors of the plugging layer,the XNCY series rigid materials were evaluated and selected in the laboratory,and their optimal gradation relationship was clarified to form a dense plugging layer and improve the pressure bearing capacity of the formation,and the indoor experimental results showed that the formula could bear pressure up to 7 MPa on the basis of the base pulp.