预测裂缝型有水气藏早期水侵动态的新方法

四川盆地气藏地质情况复杂，储集层具有明显的低孔低渗特征，非均质性强，裂缝发育程度差异较大，气井产量大幅降低并出现水淹现象。利用气藏开发早期的试采数据来研究水体的性质及早期水侵动态，基于物质平衡原理建立了水侵动态预测模型，通过计算水侵强度系数得出气藏的水侵动态指标，避免了直接计算水侵量,运用非线性最优化方法进行求解并给出了相应的解法。针对实际气藏，利用该模型计算了反映水侵动态的各项指标。研究表明，该方法可以准确获得非均质气藏水体性质和水侵动态，其结果对提出早期控水措施很有帮助。对有水气藏的开发中实施早期控水措施具有重要的实际意义。

A NEW METHOD FOR WATER INVASION PERFORMANCE PREDICTION IN THE EARLY STAGE OF FRACTURED AND WATER CARRYING GAS RESERVOIR DEVELOPMENT

The geological conditions of Sichuan gas field are complicated, including obvious low porosity and permeability, a strong heterogeneity, and the fractures having different fracture growing degrees.Because of locally active edge or bottom water, it breaks through into the gas reservoir along larger fractures, making the production of gas wells greatly reduced and the gas wells waterflooded. It also damages gas reservoirs and decreases the recovery factor. It is very important for early water control in aquifer gas reservoirs to use the early production testing data for studying the aquifer behavior and water invasion performance. Based on material balance equations, a new method for prediction of water invasion performance of fractured gas reservoirs is presented in the paper. By this method calculation of water invasion rate by introducing the water invasion factor is avoided. A nonlinear optimization solution procedure is employed and the proposed solution has more improvement than traditional method. A field example is presented that illustrates the capabilities of this water invasion prediction method for the analysis of past performance of fractured and watered reservoirs. Real case study indicates that the method can acquire the aquifer behavior and water invasion performance exactly and the results are useful to the measures for water invasion