Research On Horizongtal Well Drilling Design Optimization Of Close Sand Reservoir In Fanjia Block

Close sand reservoir is the most important resources in shengli oil field. There are more and more close sand reservoir horizontal well in fanjia block of chunliang oil production plant, the rock is turbidity sand, there is lots of clay shale above it, the size of lateral-section well is Φ152.4mm because of fracturing technique. Some trables disappeared during drilling horizontal well, such as borehole collapse,pipesticking,drill-string partial,low weight on bit,low speed of small well drilling,high pump pressure and so on. There are four questions must be done during the course of drilling design,1.casing design is done by experience method and not reference on three pressure curve;2. Azimuth is not correct because the relationship between in-situ stresses and wellbore stability is not referenced;3. Not considering drill string bulking during the course of calculation on drag and torque;4. For the small hole,the hydraulic calculation is not accurate.In-situ stress, three pressure curve are analised by the method of rock experiment,logging data,new pressure curve model,new in-situ stress model,and well trajectory,well structure is designed.According to elastic model and critical load analysis method,the drag and torque are calculated,and the result is accurate for fanjia block,and on the basis of it,the drilling string design in horizontal well is optimized.According to H-B model,the hydraulic parameter of small hole is analized,and and the result is accurate for fanjia block.The results show that the optimum design is better for fanjia block,and is benefit for decreasing of drilling accident,drilling rate,drilling time.