Well Pattern And Potential Capacity Of Infilling Wells In The Third Class Blocks

Through analyses of the current development states and major problems of the third class blocks (with 300mX300m well pattern) of Chaoyanggou Oilfield, this paper makes certain that infilling is an effective method to improve the development performance of these blocks. According to the factual data of these blocks, quantitative interrelations between well spacing density, interwell spacing after infilling and key development targets including waterflood ratio, effective driving factor and recovery are calculated. In combination with the research of economic infilling interwell-spacing, lower infilling limit of thickness and economic limit of per-well daily production, the technological and economic limits of infilling in the third class blocks are defined. On the basis of fully learning from the latest experience and recognization onto the spacing interval of low-permeability oilfields and by way of numerical simulation, here researches the rational infilling pattern and spacing interval for the third class blocks of Chaoyanggou oilfield; and under the condition of precise history matching, imitatively calculates the development targets of four well patterns: non-infilling, 150m-106m cross infilling, 150m infilling and 106m infilling; and, take consideration of actual reservoir depth, assesses the economics of these patterns in different oil prices and different discount coefficients. Results indicate that the best pattern is of 150m spacing interval and 44 wells/km2 well spacing density which could achieve the above-stated development targets and get the most economic interests. Via analyses of infilling potential of the third class blocks and comprehensive appraisal of 13 little blocks, 6 little blocks of them are optimized to be potential infilling blocks, in which 590 wells could be infilled. In addition, the economic assessments of these 6 blocks show that all their economic targets, including internal rate of return and investment recovery period both of after-tax , reach the norms evaluating productivity building of outlying oilfields. Above all, the infilling into these 6 blocks is feasible.