裸眼井中自然电场分布研究

On Distribution of Natural Electric Field in Open Hole

传统的界面电位模型认为裸眼井中自然电位分布在地层与泥浆的接触面上,这种模型不完善。根据现代电化学理论,提出了一种新的裸眼井中自然电场分布模型,该模型认为,地层的自然电场分布在整个泥浆侵入带中,沿泥浆侵入方向形成电位梯度,越接近井剖面电位越高,在侵入带末端电位消失。因此,可以得出自然电位测井的探测深度就是泥浆侵入深度,并可建立自然电位与泥浆侵入深度之间的关系。新模型是对传统模型的补充和拓展。

The traditional model used to describe the distribution of natural electric field in open hole is interfacial potential that shows spontaneous potential distributes on the interface between formation and mud. Obviously, this model is insufficient to interpret some theory problems clearly. Based on modern electrochemical theory, proposed is a new model of natural electric field distribution in open hole. The model considers that natural electric field distributes in whole mud invasion zone, and forms potential grad along the invasion direction. The potential is higher near well section, and died away at the end of the invasion zone. So, the investigation depth of spontaneous potential logging is the depth of mud invasion, and relation between spontaneous potential and mud invasion depth may be built. The new model is complement and development to the traditional model.