Research On Formation Pressure Prediction Method Using LWD Data

During the development of oil and gas bearing basin, abnormal formation pressure is a common phenomenon. At present, logging data after drill is always be used to evaluate formation pressure. While assessment after drill cannot be used to guiding drilling work and ensuring the safety of drilling in real-time, logging while drilling is considered to be used for the evaluation of formation pressure.Porosity Data, such as acoustic travel time and density, can be used to predicting formation pressure in real-time when logging while drilling which is similar to wireline logging. In China, logging while drilling is not popular in early time. Generally, porosity data and resistivity data while drilling is absent, natural gamma is measured more popular. So this paper make a research about predicting formation pressure on real time using natural gamma data.At present, it is difficult to obtain LWD data completely. Therefore, this paper mainly make a study about formation pressure prediction method based on conventional wireline logging data. Then this method will be used using LWD data. At the same time, drilling parameters are also considered to be used to verify or improve the accuracy of the evaluation of formation pressure.According to above content, a lot of study about normal logging data is made in a given area. One way has been put forward to constraint the trend line and regress Eaton coefficiention when using the method of normal compaction trend line. What’s more, on the basis of lots of statistical work, we find the possible function relationship between porosity dada(AC or DEN etc.) and GR. At this time, gama logging data can be used to evaluate formation pressure as well. Finally, limited LWD data is used to test the feasibility of the method, and drilling data is combined to optimize this method. Research result shows that the method we got from wireline logging data can be well used in the logging while drilling. In the developed area with lots of logging data, LWD data can also be used to predicting formation pressure in real-time.