喇萨杏油田开发二类油层上（下）返层系方法的确定

大庆油田二类油层一次上返开发将全面结束，二次上（下）返开发面临着选择新钻井还是利用一套井网开发的问题。为确定二类油层不同区块上（下）返开发模式，为区块开发提供依据，以北一区断东的东部区块为例，建立系统经济模型，将区块首段层系与上返层系看作一个系统，建立了不同油价下两种模式的首段层系累产油界限图版，确定了钻新井与利用一套井网开发的首段产量界限，通过建立区块经济极限含水模型、反正切含水与水驱规律曲线联解预测模型，得到区块规划上返时至经济极限含水时的阶段累产油，依据建立的经济界限图版，确定了区块上（下）返开发方式。研究结果表明，北一区断东的东部区块在油价40 美元时，应采用一套井网利用上（下）返开发，油价70 美元时，应采用新钻井的开发模式。

Determination of method for developing upward (downward) layers of ClassⅡoil reservoirs in Lasaxing Oilfield

The primary upward development of Class Ⅱ oil reservoirs in the Daqing Oilfield will terminate completely, and the secondary upward (downward) development is challenged by the choice of drilling new wells or using the existing well pattern. In order to determine the upward (downward) development mode of ClassⅡoil reservoirs in different blocks, this paper presented a systematic economic evaluation model with the eastern Duandong Block in North 1 Area as an example. This model regards the layers in initial interval and the upward layers as one development system. A cumulative oil production limit chart of the layers in initial interval in two modes was established at different oil prices, and the production limit of the layers in initial interval was determined respectively for drilling new wells or using the existing well pattern. With the economic limit water cut model and the prediction model combining arc tangent water cut and waterflooding rules, the interim cumulative oil production of the block from the time of designed upward development to the time of economic limit water cut was obtained. Based on the economic limit chart, the upward (downward) development mode for the block was defined. The study results suggest that the existing well pattern should be used for upward (downward) development in eastern Duandong block when the oil price is $40/bbl, whereas new wells should be drilled when the oil price is $70/bbl.