Research And Application Of Industrial Drilling Technology In Tight Reservoir Of Changji Oilfield

In 2012,great exploration breakthrough of tight oil in Changji oilfield has shown great potential for exploration and development.The conventional technology was adopted in the early stage,this approach often resulted in large investments and low production of single wells,so that the tight oil could not be effectively developed.How to reduce costs has become the core issue of whether tight oil can be developed efficiently.The successful development experience of tight oil in Bakken oilfield shows that,the effective way to solve this problem is to use long horizontal section,large scale staged fracturing technique and factory operation mode.In order to further accelerate the pace of development of tight oil in Changji oilfield,it is very important to develop a set of high efficiency drilling matching technology suitable for tight oil development in this area,which can reduce drilling comprehensive cost and realize effective development of tight oil in this area.In this paper,according to the study of crustal stress and borehole wall stability,the safety density window of drilling fluid is determined and the casing program is simplified.Based on the evaluation results of rock mechanics characteristics,a suitable high efficiency PDC bit sequence is selected.The indoor evaluation and optimization study of drilling fluid system are carried out,and a drilling fluid system suitable for long horizontal section safety drilling is selected.Based on the investigation of the drilling model of factory operation at home and abroad,the research idea of factory drilling is determined,the platform and wellhead optimization design model are established,and the deploying platform quantity and wellhead setting method are determined.The study of factory drilling operations and corollary equipments are carried out,the construction sequence of factory drilling operations,corollary equipments and management methods are established.The drilling fluid reuse technological system,3D horizontal well trajectory optimization design and fine control method are established.The research results have achieved remarkable field application effects,and the well profile has been successfully optimized from four section to three section.The rate of penetration is increased by 72.6~287.3% compared with the previous period,and the drilling period was shortened from 150 d to 71 d.By using conventional directional tools,it realizes safe and rapid drilling of 1800 m horizontal section in slim hole of 3D horizontal well for the first time.Adopting batch drilling operation mode and matching slideway drilling machine,which can reduce equipment relocation and the relocation and installation time of single well can reduce 3~5d,the drilling time of single drilling rig can reduce 29.24 d than that of conventional drilling.At the same time,the establishment of drilling fluid recovery processing station,connecting circulation system of the two drilling rig through the pipeline,which can achieve unified processing and performance tuning of drilling fluid under the condition that the normal operation is not affected,and the rate of drilling fluid reuse can reach 28%.