Over Smaller Oilfield Long Ping Block 2 Reservoir Waterflood Adjustment Countermeasures

With the growth of the development years, Chang2reservoir put up the importance, whice is the water sucking unusual of the part of the injection wells, water saturation rising of a small amount of oil wells, the reservoir pressure reducing and imbalance. In order to improve the development result of water injection.prolong optimal production and increase recovery ratios,it is very necessary to carry out the study of adjusted of waterflood development of Chang2Oil-bearing of Yujiaping oil area of Zi chang oilfield.Integrated regional geological data and preliminary research results, guided by multidisciplinary theories of reservoir sedimentology, logging geology, petroleum geology and reservoir development geology, based on analysis of a great deal of data of drilling, logging and laboratory experiments results of more than200waterflood development wells, the deposition and reservoir characteristics have been fixed of Chang2Oil-bearing of Yujiaping oil area of Zi Chang oilfield. Based on analysis of a great deal of data of waterflood and individual well deliverability,waterflood development of rationality and adaptability have been analytical studied. Based on the above analysis, the waterflood development adjustment of Chang2reservoir have been determined.Chang2reservoir of the study area is belonged to delta front sub-facies,and the dominant sand body are distributary channel of delta plain. The rock type is fine feldspar sandstone. Cementing materials include self-generation chlorite and calcite. The intergranular dissolved pore is the mainly accumulate space of the hydrocarbon. Chang2reservoir of the study area is low hole and medium-low permeability reservoir. The reservoir has strong heterogeneity in both of innerlayer and interlayer with obvious permeability aeolotropism.The plane distribution of spacing layer of the small layer have a greater change. The cracks show a large slope, low angle range of wedge-shaped vertical fracture characteristics.Chang2reservoir of the study area is belonged to constructed-lithologic reservoir.Relat-ively weak of the formation sensitivity had an low influence up on normal waterflood. Water-sensitivity is the most damaged for the reservoir of Chang2.To prevent the expansion and mi-gration of clay particles in the injection process is the main way to reduce reservoir damage. Because of the higher water saturation at the bottom of the reservoir, there must be higher injection strength in order to inhibit the bottom water coning at the time of waterflood development.Because of the low reservoir pressure of the Chang2reservoir of the study area,it is very necessary to augment waterflood and supply formation energy. The period of effective is4-8months for the waterflood wells, an average of about six months,after the effective yield has increased of20%-40%.The water absorption relatively uniform for the reservoir of the waterflood wells. The minely type is hole for the watched water,and waterline belt which have a certain direction,is the fastest speedily along the sand body.It’s a large of production decreasing amplitude, when we relied on the natural energy to exploit Chang2reservoir.Water injection can significantly improve the yield and recovery, and ultimately improve the development effectiveness.Maximum wellhead injection pressure is generally not more than8Mpa.The minimum flow pressure is generally more than0.65Mpa for the oil well production. The reasonable reservoir pressure level have maintained about80%of the original formation pressure. The reasonable production pressure have maintained about1.3Mpa. The rational intension of extracted oil have been2.6m3/△P*d*m and the reasonable produce liquid level have been5.4m3.On the basis of the analysis,we put forward six method to adjust old oil fields,which include the amount of52of oil wells and80waterflood wells,and to improve the development result.