Back Analysis Of Borehole Stability For Shale Formation Using Caliper Data In Shengli Oilfield

More shale formations need to be exploited in the future and main challenges related to the rock properties in drilling will occur when more additional wells are to be drilled.It means that we need a good knowledge about the wellbore instability problems.By getting a good knowledge of the field and to make a better as possible model we needed a lot of data to get a good understanding of the Shengli oilfield in Jiyang depression.A geological overview was made to see the geological perspective of the field.All the historical instability problems and mud weight was composed from previously drilled wells which was put into a three-dimensional model.This 3-D model gives a good knowledge of how the field was behaving and looked at wells as an overall picture and not just one by one.Our objective for this paper was to make a model that could be used to design a better mud weight program for the wells that are going to be drilled in the Jiyang depression in the near future.It is crucial that we need to design a mud weight program such that the instability problems will be as low as possible and reduce non-productive time due to wellbore instability.From a calculated collapse curve it is possible to find the minimum recommended mud weight that could be used when drilling the new well in the Shengli oilfield in the future.This thesis uses the back analysis technique to find the caving and tight spot using GMI-Caliper.Previous to this,GMI-Modelbuilder and Wellcheck module were used to prepare the logging data and plot lithology as well as pore pressure curve respectively and then initializing the parameter's value into GMI-Caliper to generate the abnormality along the wellbore.Thus,the process called as back analysis.The results attained were in good agreement with the published literatures and the test results can be considered as a prior index to further analyze the wellbore stability in the field in near future.