Research And Application Of Horizontal Well Water Blocking Technology In C1 Block

With the progress of science and technology,the application of horizontal well technology in the field of oil and gas field development is becoming more and more mature,but in the production of horizontal wells,water shutoff has become an ine-vitable problem.Moreover,the special structure of horizontal wells involves more problems in water plugging process than vertical wells.Firstly,the geology,reservoir and development characteristics of Block C1 are studied,and the water flooding model of Block C1 is analyzed,and the water production mechanism of horizontal wells is theoretically analyzed and studied.Then,aiming at the block,a new gel plugging agent system was developed.The purpose is to effectively select water plugging in high water bearing wells in the block,reduce water cut and protect low permeability reservoirs,and finally achieve the goal of EOR.At the same time,the factors affecting gel strength of gel plugging agent were analyzed from five factors,including monomer concentration,temperature,crosslinking agent concentration,initiator concentration and salinity.Core physical simulation experiments were carried out to evaluate the plugging performance of water shutoff agent,such as plugging performance,erosion resistance and plugging strength.Combining with traditional water shutoff technology,water outlet and water shutoff agent,three water shutoff technologies are put forward,which are general injection method,bottom hole pressure balance water shutoff method and shielding temporary water shutoff method.The application,principle and concrete steps of these technologies are introduced in detail.Finally,the plugging agent system was identified as monomer 7%acryl methyl propane sulfonic acid(AMPS)+initiator 0.7%formaldehyde and sodium sulfite ammonium per sulfate(SHMS-APS)system+crosslinking agent 0.07%methylene dipropamide(MBAM)composite gel polymer,the plugging agent system has better water plugging performance.Laboratory experiments of core flow physics show that the plugging agent has good plugging performance,plugging strength,erosion resistance and selective plugging performance.In addition,good water shutoff effect has been achieved in C1 block test,which provides technical guarantee for oil and water stabilization in this block.