Research On Parameters Sensitivity Of Horizontal Well Completions Technology

Horizontal well technology has gained so huge achievement in both quantity and quality that it has become an important technology in reservoir exploiting in recent years. Casing perforated completion and screen liner completion are two major horizontal well completion types which accounts for 91.8% in China, but there are still some problems for solving not only in theory research but also in oilfield application including completion length optimization, perforating parameters optimization in bottom-water reservoir, screen liner parameters design of cyclic steam horizontal well and these problems all affect horizontal well's production. In order to solve the above problems, the following researches are carried out:(1) choose three reservoir blocks including CN13,Z38 and BAE901 as research target and analyze horizontal well production condition as well as 5 technique indexes'influencing factors and influencing law in the three block;(2) effect analysis of permeability, viscosity, control area and bottom water condition to horizontal well optimum completion length carried out and horizontal well optimum completion length is get by using reservoir simulation technology;(3) sensitivity analysis of completion parameters'effect to horizontal well productivity is made by three models including uniform perforating,variable density perforating and screen liner completion as well as the relevant calculation software both of which have coupled reservoir flow, well-wall inflow and well-bore flow. The conclusions are:uniform perforation's perforating depth, perforating density, pollution penetration, reservoir permeability anisotropy and perforating crushed zone have significant effect to horizontal well productivity while perforating phasing angle as well as perforating diameter have negligible influence;uniform perforation's inflow profile is un-uniform owning to the effect of 5 factors including well-bore pressure drop, bottom water, oil layer thickness, reservoir permeability anisotropy and fluid viscosity, but variable density perforating can leads to relative uniform inflow profile who will delay bottom water's cresting; the major factors that influence slotted screen liner's productivity are slot length, slot density and slot blockage thickness by formation sand; the major factors that influence perforated screen liner's productivity are screen aperture density, screen aperture num per liner circle and pollution degree; reservoir permeability anisotropy will not significantly influence horizontal well productivity until it reaches as big as 3 to 4; horizontal well productivity ascends as long as the four parameters including liner diameter, slot density, slot width and slot num per unit ascend and productivity variation will gradually goes to smooth; slot blockage can lead to huge productivity lose which may be as high as 40%; optimum completion parameters zones of horizontal wells in CN13 block, Z38 block and BAE901 block are determined owning to sensitivity analysis. Research supplies theory and tool for horizontal well completion parameters optimization and application effect's improvement which can direct horizontal well's application of Z38 block, CN13 block and BAE901 block as well as afford reference research theory and method for other similar reservoirs.