Research On Reservoir Properties And Pressure Prediction For Adjustment Well

Bohai Offshore Oilfield is a heterogeneous reservoir.After waterflooding,formation fluid and pressure distribution had been changed greatly,formed a great difference between plane pressure and interlayer pressure,result in blow out,lost circulation,sticking tool,pressure kick and poor cementing during the drilling of adjustment well.In order to drill adjustment well successfully and safely,accurate prediction of reservoir properties and pressure of adjustment well is needed,as long as the design of drilling arrangement and drilling parameters such as density of drilling fluid.Prediction of reservoir properties for adjustment well such as thickness and porosity is a prerequisite of pressure prediction.This paper investigates reservoir geology of some blocks of Bohai Offshore Oilfield,analyses the distribution of reservoir properties and factors that affect pressure of adjustment well.Based on the research on the methods of prediction of reservoir properties and pressure at home and abroad,with practical situation of Bohai Oilfield,raises an improved ordinary Kriging method and use this method to predict thickness,porosity and permeability of each layer of target blocks.Using this method to predict thickness of single well in target oilfield,prediction errors are below 10%,prediction errors of porosity are below 5%,permeability prediction errors can be remained below 15%,accuracy of the result can meet the needs of engineering design.Based on fluid mechanics and fluid mechanics in porous medium,with practical situation of oilfield,raises a method to predict maximum pressure of the adjustment well and programs a program to predict reservoir properties and maximum pressure.On the basis of predicting the physical property and the maximum pressure of the adjustment well,the schemes of well control and shut in of adjustment well are given,provides technical guidance for the design of adjustment well drilling.