产水气井动储量评价方法研究

Research of Dynamic Reserves in Water-Producing Wells

动储量是确定气井合理产能和井网密度的重要依据，是编制、调整开发技术政策的物质基础。对于产水气井动储量评价，难点在于水侵造成外来压力补给，使得视压力与累计产气量不存在线性关系，无法直接利用压降曲线外推获得准确的动储量；此外传统的水侵计算模型依赖水体形状、性质，相关参数难以获取且计算过程相对复杂。因此，本文在水驱气藏物质平衡原理和水侵量计算方法研究的基础上，推导了不同生产时间下偏转压降曲线的视压力差、水侵体积系数及水侵量的关系模型，建立了利用不同时间下的水侵量校正产水气井动储量的一种简单方法。结果表明，该方法不依赖水体形状、性质，可预测早期水侵下的动储量，具有快速简便、相对可靠的特点。该方法的建立为产水气井的动储量评价提供了技术支持，为气田储量动用程度的提高奠定了基础。

Dynamic reserves are important basis lbr determining the reasonable production capacity and well pattern density of gas wells, and are the material basis for the formulation and adjustment of development technological policies. For the evaluation of dynamic reserves of water-producing gas wells, the difficulty is that it is impossible to directly use the pressure drop curve extrapolation to obtain accurate dynamic reserves, because the water invasion brings about the external pressure supply, so that there is no linear relationship between apparent pressure and cumulative gas production. In addition, the traditional water-invasion calculation model relies on the shape and properties of the water body. The related parameters are difficult to be obtained and the calculation process is relatively complicated. Therefore, based on the study of the material balance principle and water-invasion calculation method of the waterflooding gas reservoirs, the models of relationship between the apparent pressure difference, water-invading volume factor, and the water-invasion amount of the deflection pressure drop curves at different production times are deduced. A simple method of correcting the dynamic reserves of water-producing gas wells by using water-invasion amount at different times is established. The results show that the method does not depend on the shape and properties of the water body, and can be used to predict the dynamic reserves of early water intrusion. It has the characteristics of being fast, easy and relatively reliable. The establishment of this method provides technical support for the evaluation of dynamic reserves of water-producing gas wells and lays a foundation for the improvement of the producing reserves ratio of the gasfield.