Study On Technical And Economic Limits Of Production Adjustment In Shengtuo Oilfield

Shengtuo oilfield is the main production area of Shengli oilfield, which is the secondlargest oilfield in China. Since it was put into production in1965, it has experienced fourstages of development, namely the initial production period, rapid-speed producing period,high-speed stable production period and sustainable development period. The changing offluid producing shows that by means of production area transferring from main layer to otherlayer, EOR technology, and other fluid production adjustment measures such as oil productionstabilizing and water controlling, rapid production decline has been effectively controlledsince the "Ninth Five-Year plan". From the year1996to2011, annual oil production ofShengtuo oilfield declined from357×104t to270×104t, and annual output of fluid declinedfrom5986×104t to5243×104t, dropping by more than20%.When Shengtuo oilfield entered into ultra-high water cut stage, the major problems areincreasing natural decline rate, significant declining of annual oil production, poor effect ofadjustment well and downhole operation measures, low production of new drilled well andinstability of oil production. By studying and analyzing the changing rules, tendency andcause of the yearly fluid production of Shengtuo oilfield, tendency and reasons, the oilproduction is found to be closely related to fluid production. Fluid production declining is themost critical factor to oil production declining, and the main factors to influence theproduction rate are development methods, the change of work object and the imperfectinjection-production pattern etc. By theoretical and practical analysis, the effect of fluidproduction acting on development outcome is found. It shows that with enhancement of thedisplacement velocity, formation pressure and pressure differential can improve displacementefficiency and oil recovery rate. By introducing the concept of economic limit of water cut and economic limit of production, individual well production and inefficient shut-in limit ofShengtuo oilfield are discussed here, and corresponding adjustment measures are proposed atdifferent oil prices on different units. Additionally, fluid production adjustment and oilfielddevelopment cost are discussed here, and proposals of adjusting the liquid production scaleare put forward for more reasonable, economic, and scientific development of Shengtuooilfield.