相位对斜井射孔破裂压力的影响  

Impact of phase angle on the breakdown pressure of deviated wellbore in perforating

作　　者：刘欣[1,2] 刘从箐[1] 刘同斌[3] 赵立强[2] 王强[1] 

机构地区：[1]中国石油西南油气田公司采气工程研究院 [2]西南石油大学石油工程学院 [3]中国石油天然气集团公司四川石油管理局

出　　处：《天然气工业》2010年第3期55-56,共2页Natural Gas Industry

摘　　要：斜井破裂压力是压裂设计的一个重要参数,一般只能从已知射孔方位角来预测该参数。但现场采用的是非定向射孔,缺乏相应破裂压力的预测方法,而传统的破裂压力计算方法并没有获得非定向射孔井破裂压力的变化规律。为此,针对射孔斜井的主应力与射孔夹角未知的情况,利用应力分析及裂缝起裂机理,分析相位对斜井破裂压力的影响,并分析了多缝破裂压力的变化及破裂压力与裂缝延伸条数的关系。结果表明:当射孔方位角变化,各个射孔破裂压力交替地达到最大、最小值,在某个方位角,相应有多个破裂压力;其中最小破裂压力对应射孔处裂缝最先产生,通过优化射孔参数可降低裂缝起裂压力、优化裂缝延伸参数。这为优化压裂设计、降低施工风险及提高后期改造效果提供了依据。The breakdown pressure of deviated wellbore, being an important parameter of the fracturing design in perforation, can only be forecasted with the known perforation phase angle. However, as non-oriented perforation is being used in oil and gas fields in recent years, the way for predicting the breakdown pressure has not been obtained, moreover, the conventional calculation methods for the breakdown pressure failed to achieve the variation law of breaking pressures in non-oriented perforation wells. In this paper, by studying the impact of phase angle on the breakdown pressure of a deviated well in perforating, the variation range of breakdown pressure in deviated well perforating is predicted and the fracture number after perforation is analyzed. For the fact of the included angle between the principal stress and perforated hole being unknown,the mechanism of stress analysis and fracture initiation are used to analyze the impact of phase angle on the breakdown pressure and the variation breakdown pressure of multi-fractures and the relationship between the breakdown pressure and the amount of propagation fractures. The results have shown that the breakdown pressure reaches maximum and minimum values alternately with the perforating parameter being changed. At a certain perforation phase angle, there can be several breakdown pressures. And fractures are created firstly at the perforated hole with the minimum breakdown pressure correspondingly. Based on optimizing perforation parameters, the breakdown pressure can be reduced and fracture propagation parameters can be optimized. This provides foundations for optimizing the fracturing treatment design, reducing the operation risks, and improving the post-frac performance of wells.

关 键 词：水力压裂 射孔 破裂压力 应力 相位 定向井 数学模型 

分 类 号：TE257.1[石油与天然气工程—油气井工程]