The Geological Approach to Predict the Abnormal Pore Pressures in Abu Amoud Oil Field, Southern Iraq

Abstract

Anticipating pore pressures are essential for the operation of drilling success for oil and gas wells in particular that may anticipate encounter abnormal pressure, i.e. higher than normal pressure. Drilling problems such as differential pipe sticking, lost circulation and thus drilling costs, can be significantly reduced by early recognize the abnormal high pore pressures. The normal range for pressures attain to 0.433 and 0.50 psi/ft. Usual muds density is about 9 ppg. (pounds per gallon) which exert a bottom hole pressure of about 0.47 psi/ft. Meanwhile a well is in the process of being drilled, there are several parameters that indicate the presence of abnormal pressure, such as a sudden increase in penetration rate (ROP), a sudden increase in the temperature of the drilling mud, and a decreases in the density of the shale fragment. The producing wells which were used in this study are (AAm-5, AAm-4, AAm-3, AAm-2, and AAm-1.) There are many methods for predicting the abnormal pore pressures., The current study focuses on three methods were used, which are the ratio (d- exponent) method, acoustic probes method, and the shale density method. This study was conducted in the Abu Amoud oil field, (certainly in Iraq) located in the northwestern part of DhiQar Governorate. This oil field includes five oil wells, each well producing from four units. More than one method was used to find intervals of abnormal pressure for the Zubair Formation,