Research On The Interactions Between Formation Pressure Distribution And Casing Damage In Xingnan Development Block

The oil and water well casing damage is the major unsolved issues around theworld.Along with the development of degree depeen, adjust the development plan andimplementation, as well as various geological engineering and improvement measures, theoil field has different level casing damage, which serious influce the production efficiency.At present, the study of casing damage is mostly in qualitative description or simplemechanism simulation, which difficult to combine different blocks of the actual situationanalysis of the root causes of casing damage. Based on the study of existing production dataand the related data of casing damage, applicating mathematical statistical methodquantitative analyze the press and differential pressure limit of oil and water well inXingshugang oilfield11area, which gives the reference to the practice.Based on the area of the casing damage distribution of space-time, made clear with thedifferent development stage, the spatial distribution characteristics and causes of casingdamage are not the same: the casing damage well is little in early development stage, thecasing damage well number is rising with the formation pressure rising significantly in lateperiod of development. The number of casing damage wells is increase obviously after twoencryption adjustment in the southern district. The casing layer are mainly concentrated inthe sa II2sa II3sa II4and sa II5above the horizon of mudstone interlayer section inlongitudinal view. Combining the analysis of coring well data, casing damage layer ofmudstone interlayer has smectite and illile absorbent mineral, sand body heterogeneitydifference, the layers of sedimentary bodies of extremely complex. From the set of changepoint form sets of variable types is deformation and dislocation, accounted for52.94%and47%sets of variable.Combined with the geological development status and study area of casing damage theanalysis of characteristics of the distribution, indicate “water soaking in shale creep”and“pressure difference-stress coupling”is the major reason of the oil reservoirs casing inXING11areas, and that the pressure differential is the most important factors. Through theexisting production material and the materials of casing damage, Analysis of the mainfactors of casing damage and its influence of the layer pressure change, combining with theproduction unit multidisciplinary numerical simulation and measured the static pressureanalysis and comparison, Study the pressure dynamic change regulation in the southernXING areas. From a plane view, casing well distributed in the pressure gradient large partsof the plane, the plane differential pressure from the larger additional stress is the maincause of casing damage, unbalance of the layer pressure plane in the southern XING11area is more serious, for the incidence casing areas. From a longitudinal view, oil wellcasing damage is not all in the high pressure layer, the layer longitudinal pressuredifference is the cause of oil Wells of casing damage, the reasons of the layer pore pressurevertical uneven distribution, the high voltage and low voltage between layers of with larger between layers of the pressure difference, the longitudinal differential pressure of produceshear force is the important reason for the casing.Based on casing damage pilosity area (south) and the non-casing damage area (north)pressure value of the statistics and comparative analysis, choose appropriate layer pressuredifference calculation method, based on the different sections and different types of wellcasing pressure, differential pressure distribution probability analysis, determine the oilWells pressure boundary of casing damage are:12.5Mpa and14Mpa; Oil Wells of thecasing pressure differential boundaries is2.5Mpa. Use of Daqing oil field commonly usedreasonable calculation method to calculate the water injection pressure boundaries in thestudy area, in the understanding of the casing damage and regional strata stress related,comprehensive analysis of the geological development background of XING11areas, andanalyzes the reason of the unbalanced regional pressure system. Finally, for the purpose ofcontroling the casing damage, to look for abnormal high pressure layer, perfectinjection-production relation as a guide, gives the XING11division pressure systemconcrete regulating measures.