Development Effects Evaluation Of Thick Massive Sandstone Reservoir In TZ402 Wellblock Tazhong4 Oilfield

After 20 years of production and development, Tazhong4 oilfield TZ402 area CⅢ oil lower part of thick massive sandstone reservoir has entered a special high water cut stage, serious flooding in some wells.In the current study area, geological reserves recovery degree and a higher degree of recoverable reserves, the less remaining recoverable reserves, rapidly rising water, the complexed distribution of remaining oil are all manifested in the production and development issues.In this study, from the actual situation of the reservoir, combined with previous geological knowledge and reservoir dynamic analysis, and the application of basic reservoir engineering methods so as to evaluate the development effects of reservoirs. The main results of this the following results and understanding:Tazhong4 Oilfield TZ402 area belongs to Class Ⅱ reservoirs(there are some natural energy supply), of which 1~3 layersare generally of natural energy, and the formation energy is needed to complete timely for mining in the process of production.Natural energy of thick massive sandstone reservoir is relatively abundant, initial production can use natural energy to mine.The 1~3 layers to predict recoverable reserves of 325.19×104t and recoverable reserves recovery degree of 78%, which can be adjusted to further mining development programs; thick massive small layer(4~homogeneous section) forecast recoverable reserves 794.34×104t, recoverable reserves recovery degree of 97.5%, better development results, a high degree of recovery.The 1~3 layers have certain ability to extract, the extract ability of the 4~5 layersare poorer, homogeneous section basically have no ability to extract; Since the horizontal wells into production late,and lack of formation energy, the 1~3 layers’ vertical wells productivity are better than horizontal wells;4~homogeneous section of horizontal wells productivity is about four times than the vertical wells, reflecting the productivity advantages of horizontal wells. For good reservoir properties and adequate formation energy of thick massive sandstone reservoirs, so giving priority to the horizontal wells for production and development.The 1 ~ 3 layers of single well pressure drop types are fast descending, descending slowly, the initial relatively stable type of three, the average formation pressure is 23.18 MPa, the original bottom pressure is 40.02 MPa, to maintain the degree of 65.42%,keep the general level; 4~homogeneous section formation pressure drop types are descending slowly type and initial relatively stable type of two kinds, The average static pressure is 36.00 MPa, the original bottom pressure is 40.02 MPa, to keep the degree of 85.72%, keep well.In accordance with the variation of the moisture content of the study area, the reservoir development is divided into five stages: Ⅰ: 1993 ~ 1997, the water-free oil production period, Ⅱ: 1997 ~ 1999, the low- water oil production period, Ⅲ: 1999 ~ 2004 years, the rapid rising period of moisture content. Ⅳ: 2004 ~ 2007 years, water is relatively stable, Ⅴ:since 2007, the high water content period of oil production.