Research And Manufacturing Of Compressible Open Hole Packer For Horizontal Section Fracturing

Developing horizontal well is the effective way to exploit the well with low permeability or small reserves.To the hydrocarbon reservoir with extremely low permeability,large seepage resistance and bad connectedness,the usual practice is to fracture to increase the flow capacity of oil and gas.The horizontal section fracturing completion is an advanced completion technology,and it is an important well stimulation measure in low permeability reservoir.Currently,the horizontal section fracturing completion is applied widely on some onshore oil and gas fields,but for offshore oil and gas fields,the horizontal section fracturing completion tool has not been used restricted by reservoir condition and ocean condition.This research project is authorized by China Oilfield Service Limited to research section fracturing technology and compressible open-hole packer for offshore oil and gas fields with low permeability.The usual compressible open-hole packer and composite structure in oil and gas field were surveyed in this article.Several rubber barrel structures were designed,and the sealing property was analyzed by Finite Element Method software ABAQUS,and the experiments were carried out to test sealing property.The final structure composition is single rubber barrel with expendable steel back-up ring.The sealing institution,retaining mechanism and midway anti sealing mechanism were designed and checked.And the structure of single passage compressible packer is determined on the basis of the results.The dual passage compressible packer with a hydraulic passage was designed on the foundation of the single one.It could control the switch of sliding sleeve and complete a new section fracturing technology.The drawings of packers were built by Auto-CAD,and the three-dimensional models were built by Solid-works.The safety factors were calculated by lame formula and the fourth strength theory,and the results were safe.The packer would be used in open-hole horizontal section.The diameter in this section would expend to different levels.Therefore,the sealing property of the packer under the condition of different ratios were analyzed by ABAQUS.The results indicated that the packer could meet the demands in the situation of four expending ratios: non-expending,1% expanding,3% expanding,and 5% expanding.The model machine of the packers were manufactured according to the drawings,and the indoor tests were carried out.The tests succeeded after several trials and improvements.