A Research On Enhancing Drilling Rate Of Directional Interval In Fuling Oil Field

Shale gas as a unconventional oil-gas has drawn people’s a lot attention in recent years, it changes current arrangement and structure of energy system, expands the field of oil-gas production. Actually, Shale gas has been found for a long time, when drilling in mudstone and shale, it can be observed that some carbohydrate gas slosh in wellbore, always it’s considered invaluable. Generally, most of shale gas formation is in large scale, with huge thickness, and almost every shale contain gas, which can ensure shale gas well product steadily. But shale gas reserves have low permeability and production process is difficult. As drilling technology improving, horizontal drilling technique and hydraulic fracture technique have been primary technique in shale gas development.In order to accelerate the development on exploration and exploitation of shale gas, Fuling shale gas development project in ChongQin has been regarded as national demonstration zone, expecting to form efficient and effect system of drilling technique. Based on existing drilling data, Fuling has complex geological condition, vuggy and hydrate sulphide in shallow strata, poor drill ability, instability well wall, heavy leakage in Hanjiadian stratum, which increase drilling difficulties. To guarantee drilling process safety and efficiency, many measures have been taken, This paper mainly studies some drilling technique to raise drill speed of directional interval, these drilling technique include composite drilling technique, air/foam drilling which primarily solve heavy leakage in directional interval, speed-up tools which can enhance drill efficiency.Composite drilling technology reinforce rock breaking energy by improve rotate speed can reach out splendid drill effect, trajectory optimization design with reasonable built angle rate to increase composite drilling time, decrease directional drilling time can improve drilling rate effetely, in the meantime, it can ensure good well trajectory. Screw short lifetime is the main problem in composite drilling. The paper use existing drilling data by contrast and analysis, conclude that Lilin Screw has long lifetime in drilling construction, moreover, equal thickness screw show steady usage effect and long lifetime in contrast with conventional screw, rational manipulation and description can expand lifetime of screw. On the other hand ,to improve backing pressure of directional interval, Fuling zone introduce drilling assistant tools(hydro-oscillator and hydraulic thruster).From actual appliance of drilling effect, hydro-oscillator reflect better effectiveness.Complexity geology, marine formation distribution, heavy leakage in Hanjiadian and Xiaoheba stratum lead to long intermittent time in drilling constrution.Fuling introduce air/foam directional drilling technique to solve these problem, its angle built rate is 0.15-0.22°/satisfying construction requirement. Based on Fuling geological statistics, analysis the feasibility of air/foam drilling technique, it rests with formation yield water and hydrate sulphide, well wall stability. By coring in 1HF,stample rock reflect horizontal fracture without vertical fracture, formation rock pressive strength curve obviously above caving pressure curve, which can illustrate well wall stability of air/foam drilling.JY13-1HF use air/foam drilling penetrate 524.140m,have obvious speed-up effect. In air/foam drilling, heavy wear of drill pipe and poor ability of carrying cuttings become main problem, Aim at poor ability of carrying cuttings, the paper calculate minimal injection of air/foam volume by Angel model, it can provide valuable reference in air/foam drilling construction.