Share Wellbore Stability In Mechanical And Chemical Coupling Model

Clay shale wall of the instability is always the drilling engineering in a complex and difficult problem with worldwide, in order to solve this problem experts in the1940’s began to research, Until the1990’s, Into the mud wall shale much more stable field coupling model research stage, there are many different models。 These models of different level promoted the wall of the stable development, but, because more than a mud shale of the complexity of the coupling, many of the models parameter are difficult to be determined in the laboratory serious impact on the model the accuracy of the calculation model and practical。 So mechanical coupling model—chemical, establish the reasonable mechanics-chemical stability calculation model shaft coupling, the model parameters can be used to measure the change increase the practicality of the model, it is still a complex, difficult and has the great significance of the subject。This paper the research contents and some conclusions are as follows:1、Deepening the field coupling theory research。This paper established the new mechanics-chemical coupling sidewall stability calculation model, and gives the parameters in the model of the laboratory measurement, enhance model is practical。2、The clay shale intensity with the change rule of water content, and sets up the pore pressure-water content-the relationship between shear strength, and then calculated the strength parameters with the change of time relationship。 Get law:cohesion, internal friction angle with the increase of water content and decrease,the change of the strength parameters of sidewall stability’s influence is considerable,even the decisive。3、Clay shale wall of the instability is rock mechanics, chemical and drilling fluid temperature stress the result of joint action. Clay shale sidewall stability research direction also always will move towards mechanical, chemical, thermal stress coupling direction。4、Oil migration to reservoir hydrocarbon generation from this process must satisfy three mechanical condition:reservoir pore pressure than low, hydrocarbon generation reservoir porosity, reservoir hydrocarbon generation than the compressive strength of hydrocarbon generation than high。 5、Drilling process most often meet wall of instability basically can be divided into threecategories: broken body wall of instability, plastic body wall of instability and clay shale wallof instability. Among them, the clay shale sidewall instability90%or so。So, some people willbe drilling engineering of the "sidewall stability problem" called "clay shale stabilityproblem"。6、Clay shale sidewall instability in many factors, sum up can be divided into naturalfactors and human factors two aspects。7、Water-rock of chemistry occurs mainly in the near surface place, in addition to water,rocks are the main body of the system, and the atmosphere and the action process is volcanicmaterial and related to biological and human life and activities closely linked。8、 Rock sidewall stability study is a system research, in this paper, onlymechanics-chemical coupling model to a certain extent improvement, there are many factorsno consideration, need for further research。...