Numerical Computation Of Temperature Logging

Study on wellbore and formation temperature in water injection wells is the theoretical base of temperature logs in an injection profile and important in reservoir description and reservoir numerical simulation. Logging of The wells heat is still playing an important part in production after being used in late 30s,bias its great power no matter what the well situation is.what is more, temperature logging is not just on the thing we face right now,but to give a long term character. A downhole temperature model with one hole and multiple injection zones is key method in water injection wells.acorrding to other Injection Cross section logging,tempreater logging is simple,and it can breed out the interfere and contamination of diamiter of joint and apertuer gap;and it is cheap.using temperature date under the well can divide Injection Cross section of water injection wells,ditecting cement channelling, Tube leakage and External fluid flow situation. Wellbore temperature distribution has large effect on operations .In addition, the shaft thermal stress and string have the corrosive effect of the wellbore temperature. Temperature logging qualitative interpretation was only based on abnormality of well temperature log early. In recent year,the well thermometer also is correspond a development along with development of electronic technology, the accuracy and intelligent degree of the instrument raise consumedly, because of valuing the well theories of research, make well temperature log curve of interpretation the beginning turns a direction development toward the quantification .In this paper, the target is the heat transfer problem of vertical pipe (Shaft) and the porous medium (injection layer and rock). through the careful analyze of the heat transfer mechanism Underground injection wells,we can work out the establishment of a multi-injection wellbore and formation band coupling model legislation for the underground temperature. Studing The downhole temperature, it can provide a theoretical basis for quantitative explanation for the injection profile and temperature logging,. By injecting different simulated conditions and geological conditions, water injection program will be desided reasonably.Based on the conservation equations of continuum medium, combination of the dynamics of flow and heat transfer in porous media, deduce The equations of derived porous medium (the continuity equation, momentum and energy equations) . in building Downhole temperature model, shaft heattransfer can be seen as vertical pipe heat transfer, flow in Shaft can be seen as the fully developed laminar flow; Put injection layers heat transfer as the heat conduction and convection heat transfer medium, put flow in injection layers infiltration flow ; The heat in surrounding rock can be seen as porous medium heat conduction. While waterflood development, considering the mode of the heat transfer inside wellbore and the purpose layer was conduction and convection heat transfer, the heat transfer of surrounding rock was conduction, while the water well stop to inject, all had no the fluxion of the fluid both in the well tube and the infusion layerses, so transmit heat of the well tube can be regarded as conduction of continuous medium in the vertical tube, transmit heat of formation can be regarded as conduction in porous media,On this basis, combinating the actual situation of multi-reservoir water injection, building up the boundary conditions of shaft and the implanted layer. and the rock layer and the shaft and into the dynamic coupling between non-implanted layer. Put wellbore and formation temperature distribution combined organicly. Build enclosed conservation equations with initial and boundary conditions.Solving to partial differential equation with method of finite difference have to turn the successional problem to discretization,so the solving region should be gridded at first. IN the radial direction the well tube part was divided into equally spaced grid in the paper, according with R = log aa (r/rb),R denote radial coordinates; aa was base number; rb denote radius of wellbore; (i ,j) denote grid node.IN the longitudinal direction, both the well tube and formation was divided into equally spaced grid in the paper.The Paper will use difference method,find the numerical solution of mathematical model established formerly. through the analysis of different Injected parameters ,the mine shaft parameters and temperature affect the formation parameter ,find a a reasonable, practical, effective improvement program for Injection process . In studing the impact of different conditions to temperature distribution , This paper discusses a wide range of circumstances . The same time, the temperature distribution from the Underground is different, at Different times, the temperature data is also different , as the injection time is going on, the vertical extension and radial extension will be expanded. the length of time, or more precisely, the volume cumulation has a great impact in temperature logging. Generally, the older wells, the less obvious the temperature unusual used to differentiate the implanted layer is. Similarly, the silo-temperature will continue for a very long period of time, and interference with the vertical temperature profile. Therefore, the implanted layer reflected by the temperature log, may be the past injection process. When Wells entered late , If we do not change the temperature of inject water, it is difficult todifferentiate the original injection layer and the absorbent layer , This would lead the explain the temperature logging to wrong direction . during the process of temperature injection Logging, Almost not allowed or forbiden having leakage occurs. During the temperature Logging of mine,the occurs of injected or leakage is not allowed. Even if only the drums of the back flow will also lead to the failure of logging. To distinguish between the current implanted layer of old wells, the injection of hot or cold water a few hours before the mine can be useful. To reduce heat loss, we can put heat insulation layer in the shaft. Completion of the hole has little affects to the mine temperature of the implanted layer .