Abstarct: One of the most important parameters in the drilling industry is determining the safe window of drilling mud, which if this parameter is not determined correctly, it will cause great risks such as blowout, eliminating manpower and incurring huge costs. The main purpose of this study is to estimate the pore pressure and determine the safe window of drilling mud using 3D seismic data and well logs in one of the southwestern fields of Iran. This field has 7 wells, X-01 and X-06 wells were considered as validation wells. These two wells have three-dimensional pre-stack seismic data before drilling, a complete set of well logs, check shot and geological data. Initially, except for X-07 well, all the wells had no shear wave, which was estimated using regression method and linear and non-linear correlation of multiple shear wave graphs baxsed on compression wave and porosity. Also, Carroll and Castanga relations were modified so that we can use these waves in obtaining shear acoustic impedance in other wells. In the next step, we converted the 3D seismic data before loading into shear acoustic impedance using seismic inversion. The results showed that the compression sound impedance resulting from inversion in validation well X-01 and X-06 has correlation coefficients of 82 and 74%, respectively. The analysis of the results of seismic inversion showed that the sandstone reservoir of the studied Ghar laxyer has compression, shear and density acoustic impedance lower than its adjacent laxyers, and the reason for this is the presence of porosity and possibly internal fluid (water, oil or gas). After seismic inversion and obtaining shear sound impedance, the pore pressure cube was obtained using shear sound impedance, compression and density profile. The investigation and evaluation of the estimated pore pressure showed the existence of a laxyer with a relatively high pressure compared to the adjacent laxyers, which according to the geological reports of the region, this laxyer is exactly the same as the sandstone reservoir (Ghar). The agreement of 88 and 90% of estimated pore pressure and measured pore pressure (RFT) indicates relatively acceptable results in the evaluation of this field. Finally, from the agreement and evaluation between the estimated pore pressure and the mud weight of the drilling and the fracture pressure of the formation, we concluded that the drilling fluid pressure was about 200 to 300 psi higher than the pore pressure, which represents the safe window of the drilling mud, and in the future, we can use Taking advantage of this study, we can drill more wells with less risk, safer, less cost and less time.