Breaking through two bottlenecks of unconventional reservoir in Tuha Oilfield

On October 9, Tuha oilfield announced that the well mali-2-10h in the central area of Santanghu basin was drilled in 21.3 days with GRD polymer drilling fluid. The horizontal section is 1086.55m long, and the drilling period is 44% shorter than the design period, refreshing the shortest drilling period record of shale oil horizontal well in Lucaogou Formation of Santanghu. In Santanghu oil area of Turpan Hami, there are ten thousand mu of Populus euphratica forest on the ground, which is immortal for one thousand years, immortal for one thousand years after death, and immortal for one thousand years after collapse, and unconventional oil reservoirs such as shale oil and volcanic rock are underground. Underground, shale oil, volcanic rock and other reservoirs are faced with problems such as slow drilling speed and leakage. On the ground, we need to leave a green for future generations. In 2016, the technical backbone of Tuha oilfield was transferred to form a new drilling fluid technology research and development team, which is committed to the research and application of harmless treatment drilling fluid system, to explore a new technical direction for green development drilling. GRD polymer environment-friendly drilling fluid has the characteristics of reducing reservoir pollution, improving wellbore stability and controlling malignant well loss. On November 14, 2017, the first test of GRD polymer environmental protection drilling fluid system in well Hongtai 2-127 was successful. With the improvement of plugging and anti collapse ability, the technical problems such as easy collapse of Jurassic coal seam are effectively solved.

The drilling completion period is 7 days ahead of the design, and the "green drilling" in Tuha has made substantial progress. In the drilling of Huping 17-23 well in Santanghu oilfield, GRD polymer environmental protection drilling fluid has played a role of "sticking fracture", with a loss of 96.15% less than that of the adjacent well and a drilling period of 47.13 days less than that of the adjacent well, which has found a "prescription" for the treatment of malignant well loss in Niuquanhu block. Santanghu block Ma 56 is a national shale oil development demonstration area. The sidewall stability of Tiaohu formation is a very difficult problem in drilling. After more than 300 formulation evaluations and optimizations in more than two months, the new formulation of GRD polymer environmental protection drilling fluid adapted to shale oil drilling finally came out. On May 14, the drilling period of well Ma 56-282h was 21.79 days, which was 35.9% shorter than the design period, setting a block cycle record. The problem of wellbore stability of shale oil bar lake formation was effectively solved. At the beginning of this year, Turpan Hami Oilfield Engineering Institute accelerated the in-depth research and development of GRD polymer environmental protection drilling fluid. At the beginning of September, they used GRD polymer drilling fluid in well 501 of santanghutiao, drilled to 4200m, successfully completed the drilling task, and broke the 4000 meter mark for the first time. In just two years, Tuha independently developed this drilling fluid application well from 2600 meters to 4200 meters in depth, and the length of horizontal section extended from 500 meters to 1200 meters. In the near future, GRD polymer environment-friendly drilling fluid has helped to speed up the field and reported frequently: 9.67 days for niudongping 85-2 well, 8.35 days for huq30-10h well, 7.83 days for Maping 46-9 well, and 10 days for the first time for Tuha horizontal well.