Organization
School of Petroleum Engineering, China University of Petroleum, Qingdao 266580, China
CNOOC International Limited, Beijing 100028, China
CNOOC Research Institute Co., Ltd., Beijing 100028, China
Reasearch Institute of Exploration and Development, Dagang Oilfield Company, PrtroChina, Tianjin 300280, China
摘要
压裂改造已经成为我国油藏开发的主要方式。在实际试井测试中，由于地层条件复杂和井网分布不均，测试井常常不位于地层中心，因此有必要对偏心压裂井进行研究。文中首先建立了双重介质低渗油藏偏心压裂直井试井模型，根据点源理论，将压裂裂缝离散为2N段，再通过叠加和数值反演，得到实空间下的压力解析解；然后，绘制压力响应曲线并分析参数的影响规律，压力响应曲线共出现8个流动阶段，偏心距造成系统径向流段后期轻微上翘，且偏心距越大，偏心影响段开始的时间越早，其斜率越小，同时裂缝长度越长，裂缝系统对井底压力波的影响程度越大，线性流段结束的时间越晚，其持续时间越长；最后，提出该模型的解释方法，并利用实测资料对模型进行验证和曲线分析，该模型拟合精度较高，解释结果准确。
Abstract
Fracturing has become the main way to develop low permeability reservoirs in China. In the actual well test, because of the complexity of formation conditions and the uneven distribution of well pattern, the test well is often not located in the center of the formation, so it is necessary to study the fracturing eccentric well. In this paper, a well test model of eccentric fracture in dual media reservoir is established. Based on the point source theory, the fracture is divided into 2N segments, and then the pressure analytical solution in real space is obtained by superposition and numerical inversion. By drawing pressure response line and analyzing the influence law of parameters, there are eight flow stages. It is also found that the eccentricity causes slight upwarping in the later period of the system radial flow, and the larger the eccentricity, the earlier the start time of the eccentricity influence section, the smaller the slope of the eccentricity section; the longer the fracture length, the greater the influence degree of the fracture system on the pressure wave, the later the end time of the fracture linear flow section, the longer the fracture linear flow section lasts. The interpretation method of the model is put forward, and the model is verified and analyzed with the measured data. The results show that the model has a high fitting accuracy and the interpretation results are accurate.
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