PORE PRESSURE PREDICTION BY INTEGRATING CEO-SCIENTIFIC 1! DATA IN A GIVEN FIELD

Abstract

The subject of prediction of abnormally high pressured formations has received a lot of attention in Exploration and Production Company due to the complications associated with it. It can influence drilling, geological studies and production along with lowering cost without compromising safety and environment. Overpressure is the pore pressure when it has exceeded the hydrostatic pressure limits at the same depth. It is used in assessing the seal effectiveness and hydrocarbon migration pathways mapping in the exploration phase. Apart from that it assists in analyzing trap configurations and basin geometry as well as providing calibration for basin modeling. Stuck pipes and lost circulation of drilling fluids are a major cause of cost overruns for the industry. Therefore, pore pressure prediction plays a vital role for economic drilling and avoiding well control problems such as blowouts. It assists in mapping hydrocarbon migration pathways, and the analysis of trap conliguration, seal effectiveness, etc. Prediction also plays a pivotal role in avoiding too conservative casing programs leading to failure viz, target depth not being attained or wells being redrilled. The pore pressure and fracture pressure study was done on two appraisal wells located in the given field. Initially twelve other wells were analyzed for similarities with the two appraisal wells. But in the final analysis only six wells were to predict pore pressure and fracture pressure due to unavailability of well to seismic tie for the other wells. The predicted pore pressure and fracture pressure were validated using drilling dataset such as mud weights, RFT's (Repeat Formation Test) and LOTs (Leak-Off Test). The method used for the prediction in this study was the Eaton's sonic method.