The Impacts Study And Development Effect Evaluation For Strong Bottom Water Reef Limestone Reservoir In Horizontal Well Patern

L oilfield is the biggest biohermal reservoir with strong bottom water driving in China.It is a complex reservoir with four types of formation including relatively tight,tight fracture,pore vuggy,hole fracture.Since brought on line in March 1996,the water cut of this reservoir has been rising in fast rate,and the production declined rapidly.During the period from 2010 to 2016,the comprehensive water content was maintained between 95-98%,but the recovery rate was only 11.51%by the end of December 2016.The cut rising velocity of wells in different areas were different,and the effect of lateral drilling wells were poor.Therefore,it is of great significance to make clear the main factors and make a correct evaluation of oilfield development.In this paper,based on the detailed analysis and summary of the geological characteristics of the L reservoir,the following research has been carried out in the light of the problems existing in the development.(1)By means.of numerical simulation,the factors that affected the development effect of L reservoir were analyzed systematically,and the variation rules of oil recovery and the factors are obtained(2)Using the orthogonal design experiment method,this article studied of various factors of the recovery when multiple factors work together.Than the expression of recovery in fracture type reservoir and ordinary reservoir with strong bottom water was gained.In the end,considering the condition of the vertical heterogeneity in L reservoir,suitable computation method of the recovery was demonstrated.(3)Combining the actual geologic features of target field,this paper analyzed production performance of horizontal wells,and made sure the mechanism of production performance,thus to provide the basis for the late drilling and the adjustment of production measures.(4)Firstly,according to the dynamic characteristics of horizontal wells,the reservoir types in control area of horizontal well were classified.Then the key indicator system of development effect evaluation was established which was suitable for reef limestone reservoir with bottom water.Moreover the article evaluated development effect of horizontal wells in different types.(5)Based on the results of evaluation and performance analysis,considering the reservoir along the horizontal section strong heterogeneity characteristics,it could improve the effect of oilfield development by adopting the method of determining the maximum flow rate in section of horizontal well and increasing the production pressure difference.Finnally,the proposed measure was proved to be effective through the numerical simulation.