Theoretical and Experimental Analysis on Wellbore Enhancement in Fractured Formation through Tight Fracture Plugging by Drilling Fluid

Theoretical and Experimental Analysis on Wellbore Enhancement in Fractured Formation through Tight Fracture Plugging by Drilling Fluid

Junyi Liu

Drilling Technology Research Institute of SINOPEC Shengli Oilfield Service Corporation, Dongying 257100, China

Corresponding Author Email:
8 January 2019
20 March 2019
31 March 2019
| Citation



With the aim to prevent lost circulation and wellbore instability in drilling, this paper probes deep into the wellbore enhancement mechanism and tight fracture plugging (TFP), and simulates the performance of different drilling fluids. First, the wellbore enhancement mechanism of stress cage technique, which improves wellbore pressure (WP) containment, was investigated through ABAQUS finite-element modeling. It was found that WP containment could be enhanced by improving the drilling fluid plugging or propping of existing or new fractures, which curbs fracture propagation and increases hoop stress of the wellbore. Moreover, a physical model of the TFP zone was established, revealing the microscale plugging mechanism. On this basis, the author put forward a way to optimize the TFP drilling fluid and thus the WP containment: creating a TFP zones with a strong force chain network from the rigid and resilient particles of reasonable type and size distribution and fibers. In addition, a novel simulation device was designed to evaluate and simulate the dynamic plugging features of drilling fluid, and used to optimize the enhanced TFP formulas for drilling fluid at wedge fractures of different widths. The optimized formulas can improve the loss-prevention of drilling fluid and significantly boost the WP containment in subsurface formation.


wellbore enhancement, wellbore pressure (WP) containment, tight fracture plugging (TFP) zone, subsurface formation, drilling fluids

1. Introduction
2. Analysis on Wellbore Enhancement Mechanism
3. Simulation Experiment
4. Conclusions

[1]    Li Y, Jin Q, Zhong JH, Zou SZ. (2016). Karst zonings and fracture-cave structure characteristics of Ordovician reservoirs in Tahe oilfield. Tarim Barin. Acra Pereolei Sinica 37(3): 289-298.

[2]    Fu JH, Feng J, Chen P, Wei HS, Liu ZL. (2015). Simulation on wellbore pressure during dynamic kill drilling in deep water. Acra Pereolei Sinica 36(2): 232-237.

[3]    Sun ZD, Jia CZ, Li XF. (2011). Unconventional oil & gas exploration and development (upper volume). Petroleum Industry Press.

[4]    Wu C, Chen XF, Wang L. (2016). A theory on predicting drilling fluid density windows while drilling and its engineering application. Acra Pereolei Sinica 37(3): 399-405.

[5]    Morita N, Black AD, Fuh GF. (1990). Theory of lost circulation pressure. SPE Annual Technical Conference and Exhibition 43-58.

[6]    Messenger JU. (1981). Lost circulation. Pennwell Publishing Company.

[7]    Aston MS, Alberty MW, McLean MR, de Jong HJ, Armagost K. (2004). Drilling fluids for wellbore strengthening. IADC/SPE Drilling Conference Proceedings of the Drilling Conference 321-328.

[8]    Wang H, Soliman MY, Towler BF. (2008). Avoiding drilling problems by strengthening the wellbore while drilling. 42nd U.S. Rock Mechanics - 2nd U.S.-Canada Rock Mechanics Symposium.

[9]    Wang H, Soliman MY, Towler BF. (2007). Near wellbore stress analysis and wellbore strengthening for drilling depleted formations. Society of Petroleum Engineers - Rocky Mountain Oil and Gas Technology Symposium 5-16.

[10]    Wang H, Soliman MY, Towler BF. (2008). Investigation of factors for strengthening a wellbore by propping fractures. IADC/SPE Drilling Conference, pp. 669-683.

[11]    Wang H, Soliman MY, Towler BF, Shan Z. (2009). Strengthening a wellbore with multiple fractures: further investigation of factors for strengthening a wellbore. 43rd U.S. Rock Mechanics Symposium & 4th U.S. - Canada Rock Mechanics Symposium, Asheville.

[12]    Wang H, Soliman MY, Towler BF, Shan Z. (2008). Wellbore strengthening without propping fractures-analysis for strengthening a wellbore by sealing fractures alone. International Petroleum Technology Conference 2: 1140-1155.

[13]    Wang H, Soliman MY, Towler BF, Yao Z. (2016). Forming a seal independent of formation permeability to prevent mud losses-theory, lab tests, and case histories. IADC/SPE Drilling Conference and Exhibition, Fort Worth.

[14]    Van Oort E, Friedheim J, Pierce T, John L. (2009). Avoiding losses in depleted and weak zones by constantly strengthening wellbores. SPE Annual Technical Conference and Exhibition, New Orleans 26(4): 519-530.

[15]    Cali LS, Su CM, Liu JH. (2010). Analysis on pressure-bearing capacity of leakage formation. ACRA PEREOLEI SINICA 31(2): 312-317.

[16]    Kang YL, Xu CY, Tang L. (2014). Constructing a tough shield around the wellbore: Theory and method for lost-circulation control. Petroleum Exploration and Development 41(4): 473-479.

[17]    Wang G, Pu XL. (2010). Plugging mechanism of drilling fluid by enhancing wellbore pressure. Acra Pereolei Sinica 31(6): 1009-1012.

[18]    Yang P, Chen M, Jin Y, Zhu QQ, Wen H. (2012). Crack pressure bearing capacity model and its application to plugging of fractured formation. Chinese Journal of Rock Mechanics and Engineering 31(3): 479-487.

[19]    Jia LC, Chen M, Tan QM, Sun Z, Wu SY. (2016). Key factors for inhibiting fracture propagation during leakage control under pressure. Petroleum Drilling Techniques 44(1): 49-56.

[20]    Kumar A, Savari S, Whitfill DL, Jamison DE. (2010). Wellbore strengthening-the less-studied properties of lost-circulation materials. SPE Annual Technical Conference and Exhibition 2: 993-1005.

[21]    Savari S, Whitfill DL, Kumar A. (2012). Resilient lost circulation material (LCM): A significant factor in effective wellbore strengthening. SPE Deepwater Drilling and Completions Conference, pp. 390-396.

[22]    Miller ML, Scorsone JT, Whitfill DL. (2013). Development of unique equipment and materials with field applications to stop severe lost circulation. AADE National Technical Conference and Exhibition, Oklahoma City.

[23]    Loeppke GE, Glowka DA, Wright EK. (2013). Design and evaluation of lost-circulation materials for severe environments. Journal of Petroleum Technology 42(3): 328-337.

[24]    Kageson-Loe, NM, Sanders MW, Growcock F, Taugbol K, Horsrud P, Singelstad AV, Omland TH. (2008). Particulate-Based Loss-Prevention Material-The Secrets of Fracture Sealing Revealed. SPE Drilling & Completion 24(4): 581-589.

[25]    Sun QC, Wang GQ. (2009). Introductory theory of granule matter mechanics. China Science Press.

[26]    Sun QC, Hou MY, Jin F. (2011). Granule matter physics and mechanics. China Science Press.

[27]    Liu JY, Qiu ZS, Luo Y. (2015). Experimental study on lost circulation prevention of oil-based drilling fluid. Drilling Fluid & Completion Fluid 32(5): 10-14.

[28]    Sun QC, Wang GQ, Hu KH. (2008). Thoughts on several key problems of granular material mechanics. Progress in Natural Science 18(10): 1104-1110.

[29]    Liu JY. (2016). Study on wellbore strengthening drilling fluid technology. China University of Petroleum.

[30]    Wang ZH. (2014). The status and development direction of plugging technology for complex formation lost circulation. Sino-Global Energy 19(1): 39-48.

[31]    Zhang GY, Huang JJ, Zhang B. (2010). Equipment and method of formation pressure capacity. West-china Exploration Engineering 12: 82-84.

[32]    Song BT, Liu Y, Xue Y, Wu FS. (2007). Study on loss circulation control test instrument in Jiangsu oil field. Drilling Fluid & Completion Fluid 24(3): 24-26.

[33]    Lv KH. (2007). Study and application of lost circulation resistance and control technology during drilling. China University of Petroleum.

[34]    Li XJ. (2011). Research on technology of enhancing wellbore resistance capacity by plugging fracture formation. Southwest Petroleum University.

[35]    Wang G. (2012). Theory and technology on drilling fluids for wellbore strengthening. Southwest Petroleum University.

[36]     Qiu ZS, Liu JY, Zhou BY, Bao D, Song DD, Xiao CC. (2016). Tight fracture-plugging mechanism and optimized design for plugging drilling fluid. Acra Pereolei Sinica 37(S2): 137-143.

[37]    Kang YL, Yu HF, Xu CY. (2014). An optimal design for millimeter-wide fracture-plugged zone. Nature Gas Industry 34(11): 88-94.

[38]    Savari S, Whitfill DL, Jamison DL, Kumer A. (2014). A method to evaluate lost circulation materials-Investigation of effective wellbore strengthening applications. SPE Drilling and Completion 29(3): 329-333.

[39]    Wang, K, Zhang HL, Zhang RH. (2015). Comprehensive assessment of reservoirs structural fracture with multiple methods in Keshen-2 gas field, Tarim Barin. Acra Pereolei Sinica 36(6): 673-687.