Petroleum Drilling Techniques is supervised by China Petrochemical Corporation (Sinopec Group), sponsored by Sinopec Research Institute of Petroleum Engineering.
It aims to serve the authors and readers interested in the field of petroleum, and promote the development of petroleum engineering technology. Its scope covers oil exploitation, oil drilling, and oil drilling equipment.
Petroleum Drilling Techniques is included in CSCD, CA, EBSCO. Impact factor is 1.650.
The research was conducted on the thickening mechanism of crude oil during nitrogen injection in fracture-cavity reservoirs to clarify the thickening mechanism and take corresponding countermeasures, thereby enhancing the oil recovery of nitrogen injection. In this study, simulation experiments of nitrogen injection were performed to analyze the influence on crude oil from nitrogen extraction, oxygen content in nitrogen, and mixed water. The experiments showed that the oxygen content in nitrogen was the major influential factor. When the oxygen content was 1%, it took only more than 2 days to exhaust the oxygen, and the viscosity reached 18 000 mPa·s, which was 6 times the initial viscosity. When the oxygen content increased to 5%, the viscosity continued to grow to 1 122 000 mPa·s within more than 7 days, which was 366 times the initial viscosity. Emulsification with water and nitrogen extraction resulted in the same effect on viscosity: the viscosity increased 1–3 times. The results demonstrate improving the purity of injected nitrogen is the most effective way to prevent crude oil thickening of fracture-cavity reservoirs during nitrogen injection in Tahe Oilfield. It has provided a theoretical basis for solving the problem of crude oil thickening brought by nitrogen injection in fracture-cavity carbonate reservoirs.
With the rapid development of artificial intelligence (AI) technology, it has made remarkable breakthroughs in many fields. However, the application of AI in drilling engineering is still in the primary stage. A “three-wheels drive” methodology for the specific application of AI technology in drilling area was proposed to promote the application of AI technology in drilling, based on a brief description of the research situation of its application in drilling engineering. Then, business application scenarios and AI technology tools suitable for the research of AI in drilling engineering were analyzed. After putting forward a method of evaluating and optimizing projects based on the methodology with examples, the research process of AI application in drilling was illustrated by the real-time diagnosis of complex downhole failures. Finally, the shortcomings were identified and suggestions were given for the application of AI in drilling engineering, so as to promote the development of AI drilling technology.
It is crucial for drilling the horizontal sections of horizontal wells in Changning Block to uncover the reasons for borehole instability in Longmaxi and Wufeng formations and put forward the countermeasures of drilling fluid technology to strengthen the borehole stability. In light of X-ray diffraction, scanning electron microscopy, shale swelling, and rolling dispersion tests, the mechanism for the borehole instability in complex strata was revealed and a coordinative borehole stability method was proposed, i.e., “strengthening the plugging of micropores, inhibiting filtrate invasion, and preventing and retarding pressure transfer”. With the test devices such as sand-bed filtration testers, high-temperature and high-pressure filtration simulators, and microporous membranes, the additives of the oil base drilling fluid for Changning Block, which was dominated by plugging agent, were selected. An oil base drilling fluid system with strong plugging property, which was suitable for Changning Block, was developed. The system had a temperature resistance of 135 °C, a salt resistance of 10%, a calcium resistance of 1%, a poor-clay contamination resistance of 8%, a pressure-bearing capacity of 5 MPa for 400 μm fractures, and a filtration loss of 0 for both 0.22 μm and 0.45 μm microporous membranes. Its plugging effect was significant, and its comprehensive performance was better than that of ordinary oil base drilling fluids. The proposed drilling fluid was applied to more than 10 wells in Changning Block, and borehole instability was not encountered in the horizontal sections of Longmaxi and Wufeng formations. In comparison with those of the drilled wells constructed with the conventional drilling fluid technology in the same block, the borehole diameter enlargement rate in complex formations was reduced by 10.82% on average, and the construction cycle was shortened by 4.5 days on average. The research results demonstrated that the proposed oil base drilling fluid technology with strong plugging property can effectively solve the borehole instability problem in the horizontal sections of Longmaxi and Wufeng formations in Changning Block, and it is worthy of promotion and application.
Technical issues such as difficult wellbore trajectory control, low rate of drilling in formation, low ROP ( rate of penetration), wellbore collapse, and circulation loss are easily encountered in the drilling of horizontal wells with ultra-long horizontal section and slim hole in Changqing Oilfield. In light of this, difficulties in drilling technologies were analyzed in this study and some key technologies were investigated, including intelligent wellbore trajectory control based on rotary steering, near-bit azimuthal gamma imaging, and engineering parameter monitoring. Moreover, bit selection was optimized and the application of sealing water-base drilling fluid by a formed nanometer film was studied. As a result, drilling technologies for horizontal wells with ultra-long horizontal section and slim hole in Changqing Oilfield were developed, which can enable accurate wellbore trajectory control, drilling ratio increase and ROP enhancement, and can ensure downhole safety. The rotary steering technology and related supporting technologies were applied to Well Tao XX in Changqing Oilfield, and drilling was completed safely and efficiently in a 4 466 m horizontal section at a depth of 8 008 m, with the drilling ratio of 96.6%. This created a new drilling record as the deepest well in Changqing Oilfield and the longest horizontal section on land in the Asia-Pacific region. Considering the good field application effect, the drilling technologies for horizontal wells with ultra-long horizontal section and slim hole in Changqing Oilfield are worthy of wide application.
The development effect of CO2 flooding in low permeability reservoirs is affected by the gas channeling. In response to this problem, the foam comprehensive value was used as the evaluation index to establish CO2 responsive enhanced foam system by optimizing the foaming agent with a stirring method. The formula was 0.1% foaming agent alpha olefin sulfonate (AOS) adding 4.0% small molecule amine and water. Its viscosity, which was close to water viscosity before exposure to CO2, increased by more than 18 times after reaction with CO2. The results of the performance evaluation indicated the foam comprehensive value of the proposed CO2 responsive enhanced foam system could reach more than 11 times those of conventional foam systems, with obvious shear-thinning characteristics. The rheological equation conformed to the rheological model of power-law fluids. With stronger viscoelasticity than those of conventional foam systems, the proposed foam system could also be used to plug the dominant seepage channels to inhibit the gas channeling during CO2 flooding in heterogeneous low permeability reservoirs and ultimately enhance the oil recovery in such reservoirs. The research results showed that the CO2 responsive enhanced foam system could solve the problem of gas channeling and improve the development effect of CO2 flooding in low permeability reservoirs.
To fight against climate change, many countries have clearly put forward the schedule for peak carbon emissions and carbon neutrality. Low-carbon economic development has turned into an irreversible trend, and low carbon has become the target of energy structure transformation. Accordingly, it is projected that the proportion of demand for fossil energy will drop sharply, which will create severe challenges for the development of the oil and gas industry. For these reasons, analyses were made on the low-carbon transformation characteristics of economy and energy against the background of carbon neutrality and the influence of carbon neutrality on the development of the oil and gas industry. Then, the main countermeasures taken by oil companies and oil service companies for carbon neutrality were introduced, including formulating green and low-carbon development strategies, accelerating the development of low-carbon energy businesses, speeding up the research and applications of low-carbon technologies, increasing investment in the field of new energy, boosting the low-carbon development in petroleum engineering, and planning the low-carbon energy service business. Finally, suggestions were put forward for the development of the oil and gas industry in China, such as quality upgrading, the orderly low-carbon transformation of energy structure, acceleration of innovating low-carbon technologies, and the promotion of transformation and development in the oil and gas industry. This study provides guidance for China’s oil and gas enterprises to promote coordinated development between new energy and the oil and gas business and to facilitate green and low-carbon transformation and development while ensuring a safe oil and gas supply.
