The Study On The Potential And Mode Of Layer Well Pattern Adjustment For Extra-high Water Cut Oilfield

Most of the oilfield has entered the high water-cut stage in our country, and enhancing oil recovery becomes one of the key research contents now. Taking the Lasaxing oilfield as an example, this paper researched the potential and mode of well pattern adjustment, got the theoretical analysis method of well pattern adjustment during the high water cut stage about large onshore clastic sedimentary oilfield, which was the basis of the research about the high water cut stage.Lasaxing oil field is a large onshore sandstone oil field which has clastic rock sedimentation. It is heterogeneous with multiple layers .Since 1960 till now, it has entered the high water cut stage of development after many times of pattern adjustment in water flooding and large-scale of enhanced oil recovery. However, since the existence of many thin layers and serious heterogeneity, differences in producing level were still large between strata, different layers in one stratum and multiple well patterns. How to seek a new potential in well patterns adjustment and improve the producing level and oil recovery became an important topic placed in front of workers. It also related to long-term development and efficient development of Lasaxing oilfields.The main achievements are as follows:(1)Analyzed and summarized the current situation of layer well pattern adjustment in Lasaxing oilfields, simplified and classified the complex layer system and well pattern according to producing object,combination relations of well pattern and other factors.(2) Counted and analyzed a large amount of oilfield dynamic production data, evaluated the adaptability of layer well pattern adjustment during high water cut stage from producing object, strata division, injection-production system, pressure maintenance, control degree, reservoir producing and other aspects. Pointed out the main problems about the layer well pattern.(3)According to the influence factors analysis of layer pattern adjustment, built the adjustment potential evaluation model using the level analysis and neural network recognition technology. After the test of practice and application, the results of evaluation using this model have good adaptability.(4)Put the geological statistics method and field test analysis method into oilfield practice which combined the oilfield actual situation. Deduced the 5 points Law Well network technology calculation method of critical spacing, established the main technical and economic boundaries about the layer well pattern adjustment in Lasaxing oilfields.(5)Aiming at the complex layer well pattern situation during the extra-high cut stage and the development trend of enhanced oil recovery, took the long-term development of the oilfield into consideration and put forward that the direction of layer well pattern adjustment is the two or three class reservoirs potential ,adjusted the basic mode into integration of water flooding with polymer flooding .On the basis of the mode establishment, demonstrated the feasibility of layer well pattern adjustment in example of typical block assessment. Meanwhile, the analysis of field test effect further verified the feasibility of the adjustment mode.