Study On Optimization Of Increased Production Measures Of LH11-1 Reef Limestone Reservoir In South China Sea During High Water Cut Stage

The LH11-1 oil field is a heavy oil reef limestone reservoir in the South China Sea,and has abuntent OOIP,complex geological conditions,strong heterogeneity,fault and fracture development.The oil field is faced with many problems such as high comprehensive water-cut(96.3%),low degree of reservoir recovery(11.64%),complicated distribution of residual oil,shortened effectiveness of the measures to be tapped.Therefore,in-depth analysis of LH11-1 oil field development status,put forward targeted stimulation measures is the current urgent requirements.In this paper,based on the extensive investigation of the geological characteristics,stimulation measures and effects of typical carbonate reservoirs at home and abroad,combined with the geological knowledge and production characteristics of the target oilfield,the following achievements and conclusions are obtained:LH11-1 oil field is in the stable stage,the comprehensive water-cut of the oil field is high,which accords with the law of hyperbolic decreasing.The results show that the remaining recoverable reserves of LH11-1 oilfield are about 250×10~4m~3,and the main area(160×10~4m~3)is still the main development direction in the future.Based on the geological characteristics and production characteristics of LH11-1oilfield,the evaluation indexes such as the development of the fracture-vug body,the abundance of movable residual oil,the production capacity evaluation,the current daily oil production,the water-cut and the decreasing yield analysis are put forward.And the selection model based on FCEM and RBF was established.The results showed that 10wells such as A6ST2 were selected as the best consideration for the increase of production measures.Based on the numerical simulation method,it is found that after the implementation of MRC technology in A5 well,the oil recovery rate is up to 352%,and the effect of MRC technology is good.After the AICD implementation,D4ST3 is raised from 39m~3/d to150m~3/d,water-cut from 95.3%to 74.1%,water and oil effect is good.Based on TPOSIS optimization theory,A1ST4(side drilling),C7ST2(MRC)and B5ST1(MRC)were proposed from the four evaluation indexes of accumulated oil,accumulated water,technical difficulty and measure cost,A5(extract)and D4ST3(AICD water control)and other five recommended programs.Based on the TPOSIS optimization theory,the actual situation and the need,five suggestions were put forward,A1ST4(side drilling),C7ST2(MRC),B5ST1(MRC),A5(Extract)and D4ST3(AICD),from the four evaluation indexes including ten years of accumulated oil,accumulated water,technical difficulty and measure cost.