| At present,the Ta 21-4 tight oil block adopts the fracture network fracturing technology of "large well spacing,large row spacing" + "large fluid volume,large sand volume" to implement natural energy development.There is little experience for reference,and the oil characteristics,production influencing factors,development policies and development effects are not clear after fracturing.This thesis combines the geological and crude oil characteristics of Ta 21-4 block using the seepage theory,method of well test,numerical simulation method,set up different kinds of fracturing and reservoir types of percolation mathematical model,has constructed the whole life cycle of dense oil well production phase partitioning method,put forward screening criteria of test wells and determination method of reasonable time of shut-in after fracturing,the chart of limit meter oil yield index and reasonable flowback rate was drawn,and production scheduling measures for different production stages were formulated for the target block.The main research achievements are as follows:(1)Based on the seepage theory and well testing method,the seepage model of different fracturing types and reservoir types is established,and the production stage division method of the whole life cycle of tight oil well is established.The boundary control flow is used as the boundary to divide three stages.By using the calculation model,the occurrence time of each stage is obtained and the seepage characteristics of different stages are summarized.The production stages of 186 wells in the current block have been divided.At present,all wells are in the boundary control flow stage,but the wells with poor physical properties will enter the exhaustion stage;(2)Aiming at the Ta 21-4 block test wells selection mechanism and reasonable shutin time not clear problem,research and numerical simulation method based on percolation mechanism,established the test wells selection standard,and establish the method for determining the reasonable shut-in time,the test wells of the production wells in the target block are screened,32 test wells were screened out,and the reasonable shut-in time was calculated for these 32 wells,which can guide the actual field construction;(3)Aiming at the problem of unclear production scheduling measures in different production stages,the influence of production system on productivity was studied by using seepage theory and numerical simulation method,and the charts of limit meter oil production index and reasonable flowback rate were established,it is calculated that the average C value of the target block is 7.38 in the water deposition area and 5.41 in the underwater inflow zone,based on which the production discharge measures of different production stages are formulated;(4)In view of the unclear well pattern adaptability in the Ta 21-4 block,numerical simulation method is used to evaluate the well spacing adaptability of the current well pattern in the Ta 21-4 block,the analytical method is used to calculate that the well spacing in the water deposition area should be 280-760 m,and the well spacing in the underwater lake area should be 260-760 m.The row spacing of the above water deposition area should be 160-360 m,and the row spacing of the underwater inflow zone should be140-360 m,and put forward the asymmetric well spacing determination method for asymmetric fractures,which provides a reasonable basis for the subsequent block development. |
