Capacity Analysis Of Multi-layer Combined Mining Vertical Well In Complex Fault Block Reservoir

Complex fault block reservoirs are a kind of reservoirs that occupy an important position in China’s oilfield development.The geological reserves and annual oil production currently invested in development account for about 1/3 of the national total.Complex fault block reservoirs have complex reservoir structure features,faults are very developed,and there are many intricate cross-distributed faults in the reservoir,which leads to complex fault-block reservoirs being divided into fault blocks of different sizes,making complex faults The reservoir in the block reservoir is highly heterogeneous.Therefore,the analysis and evaluation of the productivity calculation and influencing factors of complex fault block reservoirs are of great significance for the development of such reservoirs.Specifically,this article mainly carried out the following aspects of work:Based on the investigation of the basic geological characteristics of complex fault block reservoirs,the classification of fault block reservoirs and the geological characteristics of different types of fault block reservoirs are summarized.According to the basic theory of reservoir seepage,the pressure drop propagation of an oil well in a completely closed fault block reservoir and a semi-closed fault block reservoir is analyzed,and the formula for calculating the capacity is derived,and the shape of the block,the area of the block and the well are in the fault block reservoir.The location and other aspects of the analysis of oil well productivity changes,and the establishment of a capacity evaluation method for complex fault block reservoirs.Studies have shown that for fully enclosed fault block reservoirs,the closer the oil well is to the center position,the closer the shape of the fault block is to the circle,the greater the production pressure difference,the smaller the fault block area,the greater the oil well productivity;for the semi-closed edge water block oil The smaller the area of the fault block,the smaller the length along the edge water direction,the closer the oil well is to the center of the fault block reservoir or the middle of the two parallel faults,the greater the oil well productivity.For the fault-block reservoirs with multi-layer mining,the inter-layer interference coefficient is used to quantitatively discriminate the interference degree between the multi-layer mining layers,summarize the geological and development factors of the inter-layer interference effects,determine the inter-layer interference coefficient,and study the calculation.The productivity of multi-layer coal mining in fault block reservoirs can effectively predict the production capacity of oil wells in different water-bearing stages during multi-layer mining of reservoirs.According to the equivalent seepage resistance method,the limit injection pressure difference of the multi-layer combined fault block reservoir and the corresponding reasonable liquid volume limit are studied.The liquid volume of the multi-layer combined fault block reservoir must be smaller than the liquid limit and analyzed.It is known that the reasonable liquid amount limit increases as the difference in permeability decreases.The reservoir numerical simulation method is used to analyze the influencing factors of complex fault block reservoirs and the inter-layer interference between layers.The study found that the simulation results are basically the same as the theoretical analysis of productivity changes in reservoir engineering theory.When multi-layer reservoirs are combined to develop the layer system,the development of the middle and high-permeability main layers should be ensured as undisturbed.For multi-layer reservoirs with severe interlayer interference,the development layer should be re-segmented for development.In actual development and application,economic cost factors,comprehensive comparison schemes,and oilfield conditions should be considered to determine the best mining method.