Method and Apparatus for Performance Prediction of Multi-Layered Oil Reservoirs

Abstract

The present invention discloses a method and an apparatus for predicting performance profiles of multi-layered oil reservoirs, wherein the method comprises: dividing the multi-layered oil reservoirs into a plurality of blocks, and determining a reservoir type, formation factor Kh and an evaluated reserves of each layer in each block; selecting a block representing geologic features of the multi-layered oil reservoirs from the plurality of blocks as a representative block, to build a fine geological model of the representative block; building corresponding fine numerical simulation model according to the fine geological model of the representative block, and determining type curves of different reservoir types under different development strategies; determining a relation curve between Kh and well injection rate for injectors and a relation curve between Kh and well production rate for producers in the multi-layered oil reservoirs under different restrictive conditions; predicting performance of the multi-layered oil reservoirs according to the type curve, the relation curve between Kh and well injection rate, the relation curve between Kh and well production rate, and the reservoir type, formation factor Kh and evaluated reserves of each layer in each block.

1 . A method for predicting performance profile of a multi-layered oil reservoirs, comprising:
 dividing the multi-layered oil reservoirs into a plurality of blocks according to reservoir types of the multi-layered oil reservoirs, and determining the reservoir type, formation factor Kh and reserves of each layer in each block;   selecting a block representing geologic features of the multi-layered oil reservoirs from the plurality of blocks as a representative block, and building a fine geological model of the representative block;   determining a relation between water cut and oil recovery efficiency of different reservoir types under different development strategies, according to the fine geological model of the representative block;   determining a relation between Kh and injection rate of single injector, and a relation between Kh and production rate of single producer in the multi-layered oil reservoirs under different operational conditions;   predicting a performance profile of the multi-layered oil reservoirs according to the relation between water cut and oil recovery efficiency, the relation between Kh and well injection rate, the relation between Kh and well production rate, and the reservoir type, Kh and OOIP of each layer in each block.   
     
     
         2 . The method for predicting performance profile of a multi-layered oil reservoirs according to  claim 1 , wherein predicting performance profile of the multi-layered oil reservoirs according to the relation between water cut and oil recovery efficiency, the relation between Kh and well injection rate, the relation between Kh and well production rate, and the reservoir type, Kh and the reserves of each layer in each block comprises:
 determining an offtake of each sublayer in each block according to the type curve, the relation curve between Kh and well injection rate, the relation curve between Kh and well production rate, and the reservoir type, formation factor Kh and evaluated reserves of each layer in each block;   accumulating the offtake of each layer in each block to obtain an offtake of each block;   accumulating the offtake of each block to obtain a total offtake of the whole multi-layered oil reservoirs.   
     
     
         3 . The method for predicting performance profile of multi-layered oil reservoirs according to  claim 2 , wherein determining an offtake of each layer in each block according to the type curve, the relation curve between Kh and well injection rate, the relation curve between Kh and well production rate, and the reservoir type, formation factor Kh and evaluated reserves of each layer in each block comprises:
 determining individual well injection rates of all water injectors in each block according to the relation curve between Kh and well injection rate and Kh of the individual well; determining individual well production rates of all producers in each block according to the relation curve between Kh and well production rate and Kh value of the individual well;   obtaining injection rate of each layer of an individual water injector by multiplying the individual well injection rate by a ratio of Kh of each layer of the well to Kh of the well; obtaining production rate of each layer of an individual producer by multiplying the well production rate by a ratio of Kh of each layer of the well to Kh of the well;   obtaining injection rate of each layer in each block by accumulating injection rates of all water injectors at the same layer in each block; obtaining production rate of each layer in each block by accumulating production rates of all oil producers at the same layer in each block;   determining the corresponding type curve of each layer according to the reservoir type and the development mode of each layer;   predicting the performance of each layer in each block according to the type curve relation between water cut and oil recovery efficiency, injection rate, production rate and evaluated reserves of each layer.   
     
     
         4 . The method for predicting performance profile of multi-layered oil reservoirs according to  claim 1 , wherein the relation between water cut and oil recovery efficiency of different reservoir types under different development strategies is represented in the form of type curves, of which the horizontal axis indicates the oil recovery efficiency and the vertical axis indicates the water cut. 
     
     
         5 . The method for predicting performance profile of multi-layered oil reservoirs according to  claim 1 , wherein in each block, each layer has one reservoir type, or layers more than a preset number have one reservoir type;
 and/or, the boundary line of each block is matched with the deployed well pattern.   
     
     
         6 . The method for predicting performance profile of multi-layered oil reservoirs according to  claim 1 , wherein the development strategies includes one of pressure maintenance level, well pattern and spacing, well type, pressure maintenance mode of water injection and gas injection, perforating strategy, oil offtake rate, injection-production ratio or arbitrary combinations thereof. 
     
     
         7 . The method for predicting performance profile of multi-layered oil reservoirs according to  claim 1 , wherein the different restrictive conditions include one of different oil tubing sizes, different lifting modes, different wellhead restrictive conditions or arbitrary combinations thereof under a given oil reservoir pressure. 
     
     
         8 . The method for predicting performance profile of multi-layered oil reservoirs according to  claim 1 , wherein determining a relation between Kh and well injection rate, and a relation between Kh and well production rate, of an individual water injection well in the multi-layered oil reservoirs under different restrictive conditions comprises:
 determining the relation between Kh and well injection rate, and the relation between Kh and well production rate, of the individual water injection well in the multi-layered oil reservoirs under different restrictive conditions in an inflow and outflow performance evaluation method.   
     
     
         9 . An apparatus for predicting performance profile of multi-layered oil reservoirs, comprising a processor configured to:
 divide the multi-layered oil reservoirs into a plurality of blocks according to reservoir types of the multi-layered oil reservoirs, and determine a reservoir type, formation factor Kh and reserves of each layer in each block;   select a block representing geologic features of the multi-layered oil reservoirs from the plurality of blocks as a representative block, and building a fine geological model of the representative block;   determine a relation between water cut and oil recovery efficiency of different reservoir types under different development strategies, according to the fine geological model of the representative block;   determine a relation between Kh and well injection rate, and a relation between Kh and well production rate, of an individual water injection well in the multi-layered oil reservoirs under different restrictive conditions;   predict performance of the multi-layered oil reservoirs according to the relation between water cut and oil recovery efficiency, the relation between Kh and well injection rate, the relation between Kh and well production rate, and the reservoir type, Kh and the reserves of each layer in each block.   
     
     
         10 . The apparatus for predicting performance profile of multi-layered oil reservoirs according to  claim 9 , wherein the processor is configured to:
 determine performance profile of each layer in each block according to the relation between water cut and oil recovery efficiency, the relation between Kh and well injection rate, the relation between Kh and well production rate, and the reservoir type, Kh and the reserves of each layer in each block;   accumulate the performance of each layer in each block to obtain an performance of each block;   accumulate the performance of each block to obtain a total performance of the multi-layered oil reservoirs.   
     
     
         11 . The apparatus for predicting performance profile of multi-layered oil reservoirs according to  claim 10 , wherein the processor is configured to:
 determine individual well injection rate of all water injection wells in each block according to the relation between Kh and well injection rate, and individual well Kh value; determine individual well production rate of all production wells in each block according to the relation between Kh and well production rate, and individual well Kh value;   obtain injection rate of each layer of an individual water injection well by multiplying the individual well injection rate by a ratio of Kh of each layer of the individual well to Kh of the individual well; obtain production rate of each layer of an individual production well by multiplying the individual well production rate by a ratio of Kh of each layer of the individual well to Kh of the individual well;   obtain injection rate of each layer in each block by accumulating injection rates of layers of all water injection wells at the same layer in each block; obtain production rate of each layer in each block by accumulating production rates of layers of all production wells at the same layer in each block;   determine the relation between water cut and oil recovery efficiency of each layer according to the reservoir type and the development strategies of each layer;   predict the performance profile of each layer in each block according to the relation between water cut and oil recovery efficiency, the injection rate, the production rate and the reserves of each layer.   
     
     
         12 . The apparatus for predicting performance profile of multi-layered oil reservoirs according to  claim 9 , wherein the processor is configured to: represent the relation between water cut and oil recovery efficiency of different reservoir types under different development strategies in the form of type curve, of which the horizontal axis indicates the oil recovery efficiency and the vertical axis indicates the water cut. 
     
     
         13 . The apparatus for predicting performance profile of multi-layered oil reservoirs according to  claim 9 , wherein the processor is configured to: when dividing multi-layered oil reservoirs into a plurality of blocks, causing in each block, each layer to have one reservoir type, or layers more than a preset number to have one reservoir layer type; and/or, causing the boundary line of each block to be matched with the deployed well pattern. 
     
     
         14 . The apparatus for predicting performance profile of multi-layered oil reservoirs according to  claim 9 , wherein the processor is configured to: determine the relation between Kh and well injection rate, and the relation between Kh and well production rate of the individual production well in the multi-layered oil reservoirs under different restrictive conditions in an inflow and outflow performance evaluation method.