Feasibility Study On The Thin And Poor Reservoir Infilling

As Daqing oil field is of non-homogeneous sandstone, with the extension of oil development and the increasing of water cut, the oil and water distribution becomes more and more complex,and the vertical multi-formation seeing water and high water-cut is common phenomena,at the same time, the potential enhancing oil recovery is more difficult for the scattered remaining oil distribution. In order to improve development performance and make up for the oil production decreasing trends, it has caused much attention about the method of economical and effective well pattern infilling adjustment. Sa-nan 4-8 zone are outer front deposition in three delta area, especially for those thin oil layer and outer stable, as the adjustment Object of three well infilling. Sa-nan 4-8 zone are mainly outside the frontier sedimentary facies, where areal heterogeneity serious, the vertical development of small thickness, and interacting with the distribution of high water-cut layer. In general, the remaining oil is always difficult to recovery after secondary well infilling. Based on this condition, new well infilling adjustment method are necessary for enhancing oil recovery and ensure stable oil production, which becomes a great challenge for petroleum industry.The fine geological description method was firstly applied on Sa-nan 4-8 zone, and a series detailed geological research results has been achieved. Combining with the data of confined core and neural network technology, the residual oil distribution was studied by comprehensive analysis methods. According to economic benefits assessment , the recoverable reserves, adjustable thickness and the latest interval layers were evaluated. Several different well infilling methods were studied and compared in order to choose a suitable infilling method. Through three field well infilling experiments in south 5 zone west block, the oil recovery achieved good results. According to the oil price at that time,by uniform well designing and partly drilling methods,411 wells were drilled in priority, well development results has been achieved.With the increasing of oil price in later, based on the water-cut conditions in this area, the adjustable thickness are determined and economical boundaries of drilling are studied by comprehensive analysis and numerical simulation. The wells waiting to be drilled were also evaluated by studying its potential economical benefits. the feasibility of third infilling wells has been studied by designing 416 wells for the third infilling wells, By above methods, the whole third wells infilling in Sa-nan 4-8 zone has been adjusted. This study results will prepare experiment for other zones or new well infilling adjustment.