A Research And Application Of Under-balanced Horizontal Deep-well Drilling Technique In Jidong Oil-field

According to the Jidong oilfield exploration and development needs, in Nanpu2-3platform (5#island) layout deep (Ordovician Carbonate Reservior) level underbalanced well, such as well NP23-P2002, well NP23-P2006, well NP23-P2013. The project construction make comprehensive of many current advanced drilling technology domestic in deep well, large displacement horizontal well, underbalanced drilling and so on, Through the deep horizontal under-balanced drilling hole cleaning, lubrication and sidewall stability technology, deep level period of underbalanced drilling technology, deep horizontal well drilling accident complicated prevention technology, oil in water drilling fluid technology, horizontal well track control and deep directional technology, so as to realize the shortening of drilling cycle, improve the mechanical drilling rate, reduce the happening of the accident complex, reservoir protection, increase production efficiency development work target.The solution of key techniques1) The big friction torque--the demand of the drilling equipment, drilling tools is high. The methods are preferred drill and supporting design, using high strength composite tool, high quality directional well tool instrument.2)Trajectory control-big deviation, long stabilization period of drill friction torque, drift is not easy to control, sliding drilling and weight on bit is difficult, drilling speed is slow. The measures are assembly to reduce button joint reduce torque, the guide motor+MWD and LWD+personalized combination of PDC drilling and improve the accuracy of well track, speed up the drilling speed.3) Wellbore stability----long open hole long construction period, borehole instability-prone soaked for a long time, anti-sloughing drilling fluid high performance requirements. Measure is the use of BH-KSM strong inhibition of drilling fluids.4) Long hole cleaning----well in highly-deviated wellbore hole cleaning problems. Measures is to enhance the pumping conditions improve, at the same time improve the drilling fluids carrying rocks, rheology and optimization of drilling parameters.5) Completion----for the high friction, it’s difficult for casing run into hole, and cementing pump pressure is high, pump speed slow to replace inefficient, cementing quality is not easy to guarantee. Program of measures is to optimize the drafting process and cementing.Conclusions and recommendations1) By3deep under-balanced horizontal well in field testing, further development of our company’s deep under-balanced horizontal well drilling technology, have created considerable economic benefits for companies; 2) Select BH-KSM strong inhibition of drilling fluids, meet the hole cleaning, lubrication, wellbore stability requirements, and also meet the requirements of reservoir protection;3) Select water in oil drilling fluids that meet the under-balanced hole section cleaning, lubrication requirements, but also meet the requirements for underbalanced drilling and reservoir protection;4) Nanpu oilfield2nd, constructed Dongying group and Shahejie group formation is hard to drill, especially Shahejie group formation pressure real strength high, grinding sexual and shock sexual strong, can drill sexual poor, three or four opened exists easy collapsed well paragraph, achieved security drilling construction most effective means is to fast win, befor collapsed cycle completed in the finished work. Personalized+LWD+high performance high temperature Motors of PDC bit drilling technology effectively in improving drilling speed in deep horizontal wells;5) Cooperate with BoHai drilling engineering technology research institute according to wellbole track situation on well Xia torque of distribution State, and size for forecast, common research reduction mill reduction twist program, and on reduction mill reduction twist tool for has scene test, in NP23-P2013well by programme using has Φ139.7drill pipe reduction mill reduction twist received Hoop, drilling well paragraph4203-5358m, drilling torque more installed Qian reduced torque6-13KNm, drilling in the maximum torque45KNm, reached has expected effect;6) Optimization of cross section through consolidation, optimization of casing program, application PDC+rapid drilling screw supporting measures, completed the nanpu oil field deep under-balanced horizontal well drilling technology;7) Adoption of3wells in under-balanced drilling, effectively handle the buried Hill formations were fractured, narrow the safe density window of drilling fluid problems, effectively control the circulation, had a positive effect on reservoir protection while maintaining well control security;8) This project examines formation deep under-balanced horizontal well drilling design technique of broad application, can be applied at other oil fields and blocks, which can effectively improve security and drilling speed in deep under-balanced drilling of horizontal wells.Through the study for optimizing suitable related technology, and in the field construction of perfect safety rapid construction technology, The deep underbalanced drilling horizontal well construction to provide the theory and the practice basis in Jidong oilfield. Project research formed in Jidong oilfield deep underbalanced drilling horizontal well technology supporting system, through the comprehensive application of these technologies, effectively solve the problem of deep underbalanced drilling horizontal well in Jidong oilfield, such as long cycle problem, effectively control the accident and complex, improve the drilling speed, and obtain good economic benefit. To account for the stability of the market and service in Jidong oilfield construction has played a positive role. This technology meets the horizontal well in Jidong oilfield to deep underbalanced drilling work demand, improve the company’s technical level.