Test model parameters.

In the contemporary energy industry, shale gas, as an important unconventional energy resource, has been widely concerned. However, the exploitation of shale gas is faced with complex geological conditions and technical challenges, one of the main challenges is that it is difficult to form discrete complex crack networks in shale, which greatly reduces the recovery rate. For different geological conditions and engineering needs, the criteria for evaluating the effect of reservoir reconstruction will be different. The XSite discrete lattice method can simulate the crack development process and provide detailed crack morphology and characteristic information (crack area, crack volume, etc.). The advantage of the orthogonal experimental design scheme is that it can obtain as much information as possible in a relatively small number of tests, improving the efficiency and cost effectiveness of the test. Therefore, based on Xsite design 6 factor 5 horizontal orthogonal test, this paper obtained the optimal fracturing design scheme with crack area, crack shape volume, tensile crack area and shear crack area as evaluation criteria. The standard deviation of each influencing factor was calculated to obtain the optimal fracturing scheme under different evaluation criteria. And considering a variety of quantitative indicators, calculate the influence weight of each influencing factor, and get the optimal fracturing scheme considering a variety of evaluation basis. Two Wells with different depth and natural fracture development were selected to verify the feasibility of orthogonal simulation test by changing fracturing fluid rate. To provide scientific basis and technical support for optimizing shale gas exploitation scheme.在当代能源产业中，页岩气作为重要的非常规能源，已受到广泛关注。然而页岩气开发面临复杂地质条件与技术难题，其中核心挑战之一便是难以在页岩储层中形成离散的复杂裂缝网络，这大幅降低了油气采收率。针对不同地质条件与工程需求，储层改造效果的评价标准也各有差异。XSite离散格架法（XSite discrete lattice method）可模拟裂缝发育过程，并提供精细的裂缝形态与特征信息（如裂缝面积、裂缝体积等）。正交试验设计方案的优势在于，能够在相对较少的试验次数下获取尽可能多的有效信息，提升试验效率与成本效益。因此，本文基于XSite六因素五水平正交试验，以裂缝面积、裂缝形态体积、张性裂缝面积与剪性裂缝面积作为评价指标，得到了最优压裂设计方案。通过计算各影响因素的标准差，得到不同评价标准下的最优压裂方案；同时结合多类定量指标，计算各影响因素的权重占比，进而得到兼顾多类评价基准的最优压裂方案。选取两口埋深与天然裂缝发育程度均存在差异的井，通过改变压裂液排量验证正交模拟试验的可行性，以期为优化页岩气开发方案提供科学依据与技术支撑。