{"id":8,"date":"2014-04-03T03:57:51","date_gmt":"2014-04-03T03:57:51","guid":{"rendered":"http:\/\/www.ofgeomech.com\/ofg20\/?page_id=8"},"modified":"2021-04-02T05:19:17","modified_gmt":"2021-04-02T05:19:17","slug":"oilfield-geomechanics-services","status":"publish","type":"page","link":"https:\/\/ofgeomech.com\/ofg20\/oilfield-geomechanics-services\/","title":{"rendered":"Geomechanics Services \u2013 Near-Wellbore"},"content":{"rendered":"\n

Pore Pressure Prediction<\/h2>\n\n\n\n

<\/p>\n\n\n\n

\n
\n

However, Pore Pressure plays a role in all geomechanical applications as the effective stresses (defined as total stress \u2013 pore pressure) controls deformation and failure of the rock.<\/p>\n\n\n\n

Pore pressure is a key parameter for Hydraulic Fracturing design <\/p>\n\n\n\n

State of the practice methodologies, Normal compaction trend – Eaton’s, Unloading- Bowers methods,  depending on the overpressure generation mechanisms – are available from OFG experience. <\/p>\n\n\n\n

At reservoir scale PPP is done using seismic interval velocities with well derived relationships (Eaton, Bowers).<\/p>\n<\/div>\n\n\n\n

\n
\"Near-Wellbore<\/figure>\n<\/div>\n<\/div>\n\n\n\n
\n
\n
\n
\n

The main objective of PPP has been to prevent the risk and expense of kicks, blowouts, lost circulation and stuck pipe for drilling applications<\/em><\/p>\n<\/div>\n\n\n\n

\n
\"Blowout<\/figure>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n
\n
\n
\"\"<\/figure>\n<\/div>\n\n\n\n
\n

How we handle PPP <\/strong>Unconventionals<\/strong>?<\/strong><\/h4>\n\n\n\n

However, Pore pressure in Unconventional shales is a very challenging task because of the ultra-low permeability that impedes a fast response of gas\/liquids inflows when drilling, even thought high overpressure may be present – no inflows detected. Also the high organic content alter the petrophysical response. So we use:\u2022Corrected Eaton using poroelasticity, a very detailed Petrophysical model and thermal maturity \u2022Empirical Equations based on TOC\u2022Temperature vs effective stress relationships (thermal maturity)\u2022Geomechanical back-analysis<\/p>\n\n\n\n

Real-Time Pore Pressure Detection <\/strong>OFG assists in the PP RT analysis and detection by streaming real-time data and importing into the models, comparing to predrill estimates, and alert for corrections when needed. We can use several pore pressure detection methods such as D-exponent, LWD, field indicators – connection gas, total gas, mud gas, ROP, PWD, and wellbore failure indicators such as cavings morphology.<\/p>\n<\/div>\n<\/div>\n\n\n\n

\n\n\n\n
\n
\n

WELLBORE INSTABILITY during drilling<\/h3>\n\n\n\n
\n
\n

Starting with the geomechanical earth model (i.e. the distribution of stresses, pore pressure and mechanical properties) along a well trajectory and then using a geomechanical tool (analytical or numerical) to evaluate stresses induced by the borehole and comparing with a failure criteria are the steps to evaluate the critical conditions to design a safe well. <\/p>\n<\/div>\n\n\n\n

\n
\"Near<\/figure>\n\n\n\n

Which is the mud window, and optimum trajectory that will produce a stable well (avoid mud losses and fracturing the formation or prevent influx and excessive failure and stuck pipes).<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n

\n
\n
\"Wellbore<\/figure>\n<\/div>\n\n\n\n
\n

Wellbore stability has been the main application of geomechanics in the oil and gas industry, to address problems of  Stuck Pipe, Kicks, Lost Circulation, Sloughing Shale, inflows. Wellbore Instability, some 41% of total NPT – are estimated to cost the industry a combined $8 billion per year.<\/p>\n<\/div>\n<\/div>\n\n\n\n

\n
\n
\n
\n

Critical Factors in wellbore Stability analysis<\/h4>\n\n\n\n