Study And Application Of Volume Fracturing In Tight Oil Reservoir In Santanghu Oilfield

One of the hot spot field of Energy Supply in recent years has been the exploration and development of tight oil and gas.The M56 Block of Santanghu Oilfield is a typical tight oil reservoir where Fracturing is the most effective technological means to develop the tight oil reservoir.This process has a very important function to enhance development and promotion of the fracturing technology of tight oil through the study of fracturing technology at the oil field.This paper is based on the achievements gained from volume fracturing of tight oil reservoir at home and abroad,including the integrated research of geological engineering.The reservoir brittle characteristics,natural fracture and reservoir.stress conditions were evaluated.Then the conditions of volume fracturing of reservoir were confirmed.Following this,the reservoir original wettability,the effect of fracturing fluid to reservoir wettability,the wettability on the the effect of water flooding oil recovery rate were evaluated.The results showed that the dense oil reservoir wettability in the study area is a weak water wethydrophilic characteristic,average relative wettability index is 0.37.After fracturing fluid in the reservoir,the reservoir was inclined to water wettability characteristics and reservoir hydrophilicity was enhanced.Different wettability core water oil displacement experiment results showed that the stronger the water wettability-the stronger the force of rock with water flooding break through later,then water flooding displacement causing crude oil,the better the results.Aiming at the single well production,the horizontal well bore azimuth and completion methods were optimized and three different forms of well pattern were designed.The 5 point well pattern of horizontal well rectangular pattern was confirmed by numerical simulation.The optimization of horizontal section length was between 600~800 m,row distance was 400 m.The mechanism of horizontal well multi-stage and multi cluster volume fracturing were studied.This optimized the fracture interval and perforation number of the target block.Main technological parameters of fracture have been optimized by using numerical simulation software technology.The key parameters,such as half length fracture,sand amount,conductivity,as well as the flow rate were determined.Finally the key factors affecting fracturing effect were summarized.The length of the horizontal lateral,fracturing scale and interval distance are the most important factor affecting fracturing effect.Thereby,horizontal lateral length has a positive correlated relationship with fracturing effect,the length of the horizontal lateral,the daily fluid production and daily oil production.Also included is the accumulative fluid production and cumulative oil production after 180 days from a single well which showed a growing trend.The above mentioned processes after 180 days continued to show an increasing growth trend.This also includes development in the single well production period with increases in the flowing production amount.When the fracture interval distance is between 80~100m,the average single stage cumulative fluid production and cumulative oil production are the highest.