A Research Of Crack Height Control And Crack Simulation Technology For Mo116Well Block Of Mo Bei Oilfield

The integral fracturing technique is an important implement in oil production and water injection improvement, which is used popularly in the low permeability oilfield. Nowadays, combined with other disciplines, and integrated overall fracturing optimizing design, crack diagnostic technology, usage and characteristic analysis of fracturing liquid and propping agent, construction technology, pressure effect evaluation after fracturing, Hydraulic fracturing technology and others, hydraulic fracturing technology has formed a systematic technology.In the construction of the reservoir fracturing, when the reservoir contains three layers of gas, oil, water, the cracks extension too high in the vertical direction will not only lead to the communication of the water layer and cause the moisture content increases rapidly, but also lead to the communication of gas layer and have the risk of bring gas into the wellbore. So control the crack height within the target layer is the key to the success of reservoir fracturing. Fracturing crack height is affected by the rock properties, formation stress difference, construction parameters and other factors. Based on the analysis of the factors that influence fracture height, combined with the actual reservoir, by choosing the appropriate effective measures of crack control, the hydraulic fracturing fracture height can be effectively controlled.This thesis aims to the low porosity, low permeability characteristics of the Northern Mo Oilfield Mol16Well Block, analyzed the crustal stress and the rock mechanical properties, Theoretically discussed a variety of factors affect the fracturing process of crack extension, and discerned out the main influence factors and secondary factors by qualitative analysis such a variety of factors. Combined with the practical situation of fracturing reconstruction of Mol16Well Block Sangonghe Formation, the effective crack control method has been put forward. According to the different geological conditions, the distribution model of the oil layer, intercalation and insulating layer has been designed. Then simulated and optimized hydraulic fracture crack to different geological conditions by using FracproPT fracturing design software. Main obtain the result as follows:1、Main Factors affecting the fracture height control in the fracturing process are physical properties of rocks, formation stress difference, and fracturing fluid performance, etc. Among them the construction displacement, the stress difference between oil layer and insulating layer, the thickness of perforation and the fracturing fluid viscosity. According to the actual situation, the major controllable factors have been screened out such as construction displacement and fracturing fluid viscosity. Aim at these two factors, by using the appropriate measures, achieve the purpose of control of fracture height has been achieved.2、Mo116reservoir contains the following four reservoir types:structural reservoir with bottom water; structural reservoir with edge water; edge water structure reservoir with condensate gas cap; bottom water structures reservoir with condensate gas cap. According to the geological condition of J1s21layer segment and J1s22layer segment, the distribution model of the oil layer, intercalation and insulating layer has been designed out. Through the change the number of single intercalation and the thickness of single oil layer, single intercalation and single insulating layer, the different reservoir span can be realized corresponding to the geological conditions of J1s21layer segment and J1s22layer segment.3, On the basis of the optimization scheme, the optimization of fracturing material and fracturing process have been done. The selected fracturing fluid system is guar gum fracturing fluid; the selected proppant is Yixing ceramsite; selected fracturing string combinations are:51/2"P110casing,27/8"+31/2"P110combined string as fractured tubing.4、According to the artificial fracture optimization scheme under different geological conditions, combining with the optimized fracturing material and fracturing process, using FracproPT software for simulation, making the artificial layer by interval inject the100mesh sand, using variable displacement sand-up technology and optimizing the construction scale, we have found out the reasonable pump injection program and control the fracturing crack height successfully.5Optimum displacement range for J1s21layer is2.23～3.18m3/min,2.87m3/min in average; optimum displacement range for J1s22layer is2.54-2.86m3/min,2.78m3/min in average. Optimum preflush percentage for J1s21layer is35%, optimum preflush percentage for J1s22layer is30%. Optimum aggregate ratio range for J1S21layer is17.54%-24.35%,20.22%in average; Optimum aggregate ratio range for J1s21layer is20.74%-26.65%,24.12%in average.