Research Of Single Well Water Plugging And Profile Control Adaptability For Carbonate Reservoir In Tahe6-7Oilfield

The fracture-cavity carbonate reservoir of Ordovician formation in the TaheOilfield has rich fracture and cavity which are diversity in size and shape and widedistribution, solution pores as the main storage space, and fracture is the primary flowchannel, while matrix has almost no storage capacity and permeability. Because thefracture-cavity carbonate reservoir has abundant bottom water, wells have highproductivity in the early stage; but it also led to almost all the wells high water cut atthe late stage. So, the rapid increase of water cut is the one of most important problemduring the reservoir development which resulting in fast natural decline, and hasinfluenced the effect to oilfield development. So how to effectively control waterconing speed is the key to improve the overall development effectiveness andenhanced oil recovery. Water plugging and profile control is an effective measure tocontrol water coning, but because of complicated reservoir type, the oil-waterdistribution and water breakthrough mode is difficult to judge, resulting in lowefficiency.Based on the evaluation of the development effectiveness of Tahe oil field, thereare currently50oil wells with high water cut, accounted for42%of the total numberof wells, and water coning is the main contradiction that affects the developmenteffect of the block, it serious impact on the use of reserves.In order to carry out the effective comprehensive treatment, using of welllogging response characteristics to identify the reservoir type, and studying on thewater breakthrough type and water rising laws. In order to analyse the high water cutin oil well, improve water efficiency, this article conducts the research to the waterchanneling. Based on the plugging effect analysis, proposed a new method to identifywater channeling, and according to the statistics, water channeling identificationstandards are given and classified the channeling strength. Based on the waterchanneling recognition, cave development rule and rise of water dynamiccharacteristics to analysis the mode of breakthrough and the flooding mechanism.Concluded that: firstly, water exit depth is the same as cave development area;secondly, because the wide fracture is the main channel for migration of oil, waterplugging is easy to block the water but also blocked oil; thirdly, wide fracture is the water exit of fast increasing of water cut, and narrow fracture is the main water exit ofslow increasing of water cut.Based on the influence factors of water plugging effect analysis, concluded that:firstly, because of water shutoff is easy to form effective clapboard in fracture-cavitywells, the plugging agent can long retention and releasing the remain oil in; and thefracture type after water plugging, the oil increment is less, and the plugging agentcan hardly retention in the cave, which is difficult to effectively plugging waterchannel. Secondly, because of tight zone can delay water breakthrough, waterplugging is better. Thirdly, the well which have slow increasing of water cut have abetter water plugging effect, however, there would be bad water plugging effect if thewell have fast increasing of water cut. And build up the principle of well selection.Finally, according to the current development status of water injection, andanalysed its corresponding effect. Through the analysis of injection-productionrelation, reservoir characteristics, inter well connectivity and potential, the potential ofprofile control and water plugging are discussed.