涩北气田全气藏关井测试资料特征分析

The Characteristics Analysis of Sebei Gas Field All Gas Wells Shut-in Test Data

涩北气田的全气藏关井测试资料存在两大特征:①约10%的压力测试曲线存在后期持续下掉、早期压力曲线异常波动的现象;②所有的全气藏关井测试双对数曲线后期上翘。特征1加大了试井分析的难度,特征2使现场无法准确区分井间干扰和边界反映。为此结合涩北气田测试井地质特征及开发状况,首先对引起全气藏关井测试曲线异常的原因进行分析,得知引起全气藏关井资料异常的原因有地层出水、井筒漏气及层间倒灌;其次利用多井试井分析方法,研究了考虑井间干扰的全气藏关井试井模型。通过该模型对涩北气田全气藏关井测试资料进行分析,得知引起涩北气田全气藏关井测试双对数曲线后期上翘的原因为井间干扰,并非边界反映现象;并利用现场实测资料进行应用分析,得到可靠的试井计算结果。研究的全气藏关井试井模型为涩北气田开展试井分析提供理论支撑,这套关于全气藏关井测试资料特征分析的方法及结论为国内同类气藏开展全气藏关井、进行选井选层提供重要参考。

There are two characteristics of Sebei gas field all gas wells shut-in test data： The one is about 10%pressure curve down continuously in the late and pressure curve abnormal fluctuations in the early of the all gas wells shut-in test data. The other one is all curves of dual-logarithm pressure curve and pressure derivative curve become warped in the late shut-in about all gas wells shut-in test. The first characteristic increased the difficulty of well test analysis and the second characteristic made the researchers unable to accurately differentiate the characteristic is boundary reflection or well interference. In order to deal these problems,based on the test well geological characteristics and development situation of Sebei field,first analyzed the reasons that caused the test curve anomaly and known that the reasons include the following formation water,shaft leakage and interlayer flow backward.Secondly using well test analysis method of multiple well,studies the all gas wells shut-in well test model that consider the well interference,and then using this new model analyzed the all gas wells shut-in well test date,known that caused the test curve anomaly reasons is well interference not boundary reflection. Finally using the new model to calculate the all gas wells shut-in test data,get the sufficiently accurate results. These studies provide an important theoretical support for Sebei gas field to analyze the all gas wells shut-in test date. At the same time,these studies provide the important reference for gas reservoir that like the Sebei gas field to carry out the all gas wells shut-in test and select well or layer.