丛式水平井组整体压裂工艺技术在致密低渗透气藏中的应用

为进一步提高鄂尔多斯盆地大牛地气田盒1段气层的储量动用程度、评价水平井组开发的经济技术可行性，开展了以多级管外封隔器分段压裂为主导的水平井组工程压裂工艺试验。首先对丛式水平井井组压裂方案进行优化，结合井场地面情况及井身轨迹，优选了压裂工艺、压裂顺序；其次，结合储层工程地质特征，单井录井、气测、随钻伽马等资料以及井网条件，研究了不同的压裂裂缝参数及设计施工参数，并开展了相邻两井同步压裂技术研究；第三，结合施工参数及裂缝监测结果对设计参数进行了实时调整，形成了丛式水平井组分段压裂优化设计工艺技术及其压裂现场优化调整技术；第四，针对现场大规模施工及同步压裂试验易出现的突发情况，制订了详细的应急预案，确保井组压裂成功实施。最后在A井组进行了6井46段现场试验，压后井组天然气无阻流量达77.63×104 m3/d，为该气田致密砂岩气藏的高效开发提供了技术支撑

Application of overall fracturing technology for cluster horizontal wells to the development of low-permeability tight gas reservoirs in the Daniudi Gas Field, Ordos Basin

In order to further improve the producing degree of reserves of the 1^st member of the Lower Shihezhi Fm (hereinafter referred to as He 1) in the Daniudi Gas Field, Ordos Basin, and assess the economic and technical feasibility of developing cluster horizontal wells, such pilot tests were carried out dominated by staged fracturing with multiple external casing packers. First, the fracturing scheme was optimized for cluster horizontal wells; the fracturing process and sequence were selected according to the field ground conditions and well trajectory. Second, various parameters of fractures, design and construction were studied, as well as the simultaneous fracturing technology for two adjacent wells based on the engineering geological features of the reservoirs, relevant data of single well logging, gas logging, LWD gamma, and the well pattern condition. Third, the design parameters were adjusted in real time according to construction parameters and fracture monitoring results, thus the optimization techniques were formed in the design and actual application of the staged fracturing treatment of cluster horizontal wells. Fourth, a specific emergency response plan was prepared preventing any possible risks in either the large scale construction or simultaneous fracturing test, so as to ensure successful fracturing in cluster horizontal wells. Finally, pilot tests were performed in 46 well sections of 6 wells in the cluster A. Upon fracturing, the open flow of this cluster well group reached 776,300 m3/d. This study provides technical support for efficient development of tight sandstone gas reservoir in the Daniudi Gas Field, Ordos Basin.