The Research On Non-Newtonian Zone Flowing Law Of Bohai Heavy Oil In Huff And Puff Process

Bohai oilfield is rich in heavy oil,which is an important alternative resource for offshore crude oil.However,it is difficult to satisfy the basic economic threshold for the heavy oil thermal recovery of offshore oil field when we apply the well pattern in onshore oilfield into offshore oilfield.The non-Newtonian fluid zone shall be considered when design well spacing and well pattern.To research the flowing law in the non-Newtonian fluid zone,three zone were divided when oil and water flow together in porous media and the non-isothermal flow model was established that considering the effect of varied threshold pressure gradient and fluid rheology.Then to solve the new model,the methods using to calculate the linear reservoir temperature,the heating radius,the mean reservoir pressure and the water saturation were given.And at the same time,some indoor experiments were carried out,so that the abnormal point and the threshold pressure gradient could be obtained from the experiment data.Finally,the MATLAB software was used to calculate the reservoir temperature,to distinguish different flow zones,and to analyze the flowing law of Lvda 21-2 oilfield.The rheological experiment results show that the abnormal points of Lvda 21-2oilfield and Nanpu 35-2 oilfield are 63.52?~64.7?and 54.5?~55.5?,respectively.The displacement experiment has determined that the threshold pressure gradient of Nanpu 35-2 oilfield flowing in the porous media is 0.147MPa/m,and is 0.0132MPa/m smaller than the calculation result.Assuming that the reservoir temperature will change in a liner manner with the distance from the injection well.And based on this,the calculated heating radius is 1.352 times of that calculated by the Marx-Langenheim method,and the oil rate is much smaller than that of Marx-Langenheim method.