Research Of Rock Physics Characteristic And Its Engineering Application Research In Silirian Strata In Tazhong Area Shun9Wellblock

The Silirian tight sandstone reservoir is the key aera of the upper Paleozoicclastic rock exploration in Shun9wellblock.The good oil and gas appearance in theKeping tager group shows that the Silirian strata in this area has great potential of oiland gas.Study of the physical characteristics and the stress of rock in this area has arealistic significance in deep （＞5000m）tight sandstone’s effectively development ofthis area.This paper is based on the collected tested data,the geological analysis data,theengineering data of the research area,at the same time,we carried out the physicaltests,rock mechanical tests under uniaxial and triaxial condition,diffential straintests,acoustic emission tests and the paleo magnetic tests of the selectedsamples,based on these experiments,wo obtained a lot of data of rock mechanics andthe ground stress’s valued and direction.With these parameters,Using the loggingexplaination method to explain the mechanical parameters and the stress with loggingdata in this area’s purpose layer,at the same time,seted up the pressure profile offracture pressure, collapse pressure and pore pressure,the conclusion in this paper canbe allowed for as an reference for the subsequent project construction or thedetermination of the safe density window.In this paper,it shows that the rock mechanics parameters and stress in Silurianstrata is complex mostly because of the condition of high temperature,high pressureand saturate the formation water.The condition of three principal stress in the purposelayer of the research area is: σv＞σH＞σh,this kind of combination represent thenormal pressure system.The direction of σHis in the north east,at some area,due to theinfluence of fault,the direction can make a change.Discussed the relationship of rock mechanics parameters,stress,collapse pressureand the lithology respectively.It shows that there are good relationship between theparameters of young’s modulus, poisson’ tatio, compressive strength, tensile strengthand the lithology,but the relationship between cohesion, internal friction angle and thelithology is not very good;there’s correlationship between the value of horizontalprincipal and the lithology,in general,the value of stress in mudstone layer is slightlysmaller than the sandstone section nearby,but with the increase of depth,the relationship of them is becoming much more complex and changeful.According to thevalue of three calculated principal stress,we can characterize the activity ofunderground rock or fault;the relationship between collapse pressure and the lithologycan be described as: the collapse pressure is bigger than the pore pressure when thestrata’ lithology is shale,but the collapse pressure is a little smaller than the porepressure when the strata’ lithology is sandsone.Discussed the application of nonlinear criterion in rock mechanics parametersand compared the prediction accuracy of different nonlinear criterion.It shows,thenonlinear criterion can provide high precision in predicting the rock mechanicsparameters,thus expanded the method for interpreting the rock mechanicalparameters,but the applicability of these methods still need further examination.The study in this paper has a certain reference value for later oilfield engineeringconstruction,parameter optimization,horizontal direction,reservoir reconstruction, etc.