Prediction Of Three Pressure Profile And Fracturing Height Logging In Longdong Area

The gas reservoirs in Paleozoic Permian of longdong region in Ordos Basin buried in a deep depth with complex geological conditions, it’s a typical low porosity,low permeability and low formation pressure reservoirs. Accidents such as borehole breakout and collapse off the block are aways happen during drilling. In order to prevent the collapse of the wall, to ensure the safety of drilling, mud weight window rational choice is very important. Besides, natural capacity of most of the wells are low, fracturing and other stimulations to improve the production of single well are needed. At present, Longdong area accumulated plenty of DSI logging data and conventional logging data, Using these logging data, we can accurately calculate the rock parameters, stress, three strata pressure, and forcast reservoir fracturing parameters, it has an important guiding significance to quality and efficient,safety drilling and production Engineering.In this paper, the gas reservoir buried in ShiHezi He8section and Shanxi Shan1section were the studied. As the theoretical basis of elasticity,rock mechanics and fracture stimulation renovation technology, mainly about five points are focused:①Logging acoustictime extraction and rock mechanics parameters were calculated.②stress, three formation pressure were computing and their profiles were built.③Fracturing propagation prediction methods by logging were researched.④Fracturing effect Logging forecast and comparative analysis of the results.⑤Programming optimization, data analysis and processed wells. There are four main achievements as the following:(1) The author has collected drilling, geology, logging data in work aera, and extracted P-S wave offset time from DSI logging data. the model of rock inherent strength were also established. the dynamic mechanics parameters has converted to static rock mechanics parameters with the relationship of the dynamic-static mechanics parameters. The sections of rock mechanical characteristics in the workplace were established, and the rock mechanical properties profile in work area were obtained;(2) For the "three lows" feature in Longdong area, ground stress calculation model was improved, formation pressure calculation formula was preferred, The stress and the three formation pressure profile were established,and reasonable mud density window was determined;(3) Optimizating and improving the forecast models of the fracture height and width, and exploratory research the forecast of the fracture length, compare the prediction results with the Fracturing achievements and the FracproPT simulation results, and accurate assessment the fracture stimulation effect;(4) Based on the Forward.net platform, the author has compiled the stress,three formation pressure calculation program and the hydraulic fractures extended forecast program, and has processed several wells. The profile of rock mechanics parameters,the stress and the three tormation pressure of five wells in work aera has been established, and the fracturing propagation conditions of three wells has been forcasted and analysised.Through these studies, a set of computing stress, three formation pressure and fracture extension methods and techniques were established with logging data. It can be used to determine a reasonable window of mud density and predict fracture propagation,the results of which is reliable,and has a good comparability with log interpretation software and fracture forecast software.