METHOD FOR WELL DRILLING AND DEVELOPMENT OF MULTIHORIZON HYDROCARBON FIELD CHARACTERIZED BY NON-UNIFORM GEOLOGICAL CONDITIONS OF PRODUCTIVE BED ATTITUDES Russian patent published in 2007 - IPC E21B43/14 E21B7/04 

FIELD: oil and gas industry, particularly for drilling and development of multihorizon hydrocarbon (oil, gas or gas condensate) field in the case of low-permeable producing reservoir with abnormally high pressure sitting over main object, namely high-permeable producing reservoir, to be developed.

SUBSTANCE: method involves drilling wells to lower reservoir; performing prior bypassing of fluid from high-pressure reservoir into fluid spread zone in low-pressure reservoir under pressure control, wherein the fluid spread zone is bounded by fluid-water contact and above fluid bypassing is carried out under closed well heads; exploiting the reservoirs. Field is developed with well clusters drilled in two stages. At the first stage bypass wells are drilled in each well cluster to provide fluid bypassing from upper high-pressure reservoir into lower low-pressure one. Bypass wells have multi-branch ends terminating inside each reservoir. Impervious barrier, for example cement bridge, is arranged over interval of side well branches drilled in upper low-permeable reservoir. Side branch communicated with lower high-permeable reservoir is drilled over the impervious barrier and then the impervious barrier is penetrated. At the second stage after reservoir pressure reduction within upper high-pressure reservoir opening interval up to value exceeding hydrostatic pressure value by not more than 5-10% producing wells are drilled in each well cluster. Fluid is extracted from lower reservoir.

EFFECT: reduced capital outlays and increased efficiency of total development of both reservoirs.

1 ex, 2 dwg