机构地区:[1]中国石油大学(北京)人工智能学院 [2]油气资源与探测国家重点实验室 [3]中国石油新疆油田公司玛湖勘探开发项目部 [4]中国石油新疆油田公司工程技术研究院
出 处:《天然气工业》2023年第7期55-62,共8页Natural Gas Industry
基 金:国家自然科学基金优秀青年科学基金项目“油气井流体力学与工程”(编号:52122401)。
摘 要:水平井多簇射孔分段压裂是非常规油气储层体积压裂改造主体技术之一,然而我国非常规储层普遍非均质性强,水平井段不同位置裂缝起裂压力差异较大,多簇射孔难以保证簇间裂缝的均衡起裂扩展,因此,亟须精细评价水平井段岩石强度的差异性,优选岩石强度相近井段布缝,以达到均衡改造的目的。为此,基于钻录井数据,建立了水平井段钻头井底机械比能无监督聚类模型,考虑了钻柱摩阻、复合钻进和射流辅助破岩等因素对井底机械比能的影响,获得了分米级空间分辨率的井底机械比能分布和聚类类别;最后综合考虑缝间应力干扰、套管接箍位置、桥塞位置和井底机械比能聚类结果,形成了以均衡改造为目标的水平井体积压裂布缝优化方法。研究结果表明:(1)相较脆性指数、泊松比、应力差等因素,射孔孔眼冲蚀面积与井底机械比能相关性较高,井底钻头机械比能可有效表征水平井段射孔簇进砂量的差异性,能够作为优选布缝位置的重要指标之一;(2)钻录井数据清洗与平滑、手肘法优选聚类数是获取井底机械比能聚类结果的关键步骤,可实现分米级分辨率区分井底机械比能的差异性;(3)优选了段内井底机械比能均值10%范围内布置射孔簇,所编制的计算机算法能自动优选压裂段簇位置,实现了段间距和簇间距的差异化设计。结论认为,该项研究成果可进一步提高非常规油气储层体积压裂布缝效率和压裂改造均衡性,该技术有望为非常规油气储层水平井体积压裂布缝优化提供思路和新方法。Multi-cluster perforation and multi-staged fracturing of horizontal well is one of the main technologies in volumetric fracturing stimulation of unconventional oil and gas reservoirs,but unconventional reservoirs in China are generally of strong heterogeneity,which causes different fracture initiation pressures in different positions of lateral,making it difficult to ensure the balanced fracture initiation and propagation between clusters in multi-cluster perforating.It is in urgent need to precisely evaluate the difference in rock strength in lateral and determine the well section with similar rock strength to deploy fractures,so as to reach the goal of balanced stimulation.Based on the drilling and logging data,this paper establishes an unsupervised clustering model of mechanical specific energy of bit at the bottomhole the lateral.Then,the influence of drill string friction,composite drilling and jet-assisted rock breaking on the mechanical specific energy is analyzed,and the distribution and clustering categories of bottomhole mechanical specific energy with decimeter spatial resolution are obtained.Finally,a fracture deployment optimization method for horizontal well volumetric fracturing aiming balanced stimulation is developed by comprehensively considering inter-fracture interference,casing collar position,plug position,and clustering result of bottomhole mechanical specific energy.The following results are obtained.First,compared with brittleness index,Poisson's ratio and stress difference,perforation erosion area is in a stronger correlation with the mechanical specific energy,and the mechanical specific energy can effectively characterize the difference in the amount of proppant injected into the perforation clustesr in the lateral,so it can be served as one of the important indicators for the selection of fracture deployment position.Second,the drilling and logging data cleaning and smoothing and the clustering number selection by the elbow method are the key steps to obtain the clustering results of
关 键 词:非常规油气 智能压裂 水平井压裂 压裂设计 机械比能 无监督聚类 射孔簇 参数优化
分 类 号:TE357.1[石油与天然气工程—油气田开发工程]
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