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Monitoring Concentrations of Particulate LCM Added to Mud Systems for Wellbore Strengthening

IP.com Disclosure Number: IPCOM000237590D
Publication Date: 2014-Jun-25
Document File: 4 page(s) / 112K

Publishing Venue

The IP.com Prior Art Database

Abstract

Controlling circulation loss of drilling fluid during well construction is more than just selecting the proper type of lost circulation material (LCM). A fully engineered approach is required. This approach incorporates borehole stability analysis, equivalent circulating density (ECD) modeling, leak-off flow-path geometry considerations, drilling fluid type and LCM material selection to help minimize pressure effects on ECD, prevent data acquisition interference with on-site monitoring tools such as pressure-while-drilling (PWD), and the assurance of timely applications of LCM treatments. In many cases, the success or failure of LCM will be largely dependent on the decisions taken and methods employed when using the LCM.

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Monitoring Concentrations of Particulate LCM Added to Mud Systems for Wellbore Strengthening

Introduction

  Controlling circulation loss of drilling fluid during well construction is more than just selecting the proper type of lost circulation material (LCM). A fully engineered approach is required. This approach incorporates borehole stability analysis, equivalent circulating density (ECD) modeling, leak-off flow- path geometry considerations, drilling fluid type and LCM material selection to help minimize pressure effects on ECD, prevent data acquisition interference with on-site monitoring tools such as pressure- while-drilling (PWD), and the assurance of timely applications of LCM treatments. In many cases, the success or failure of LCM will be largely dependent on the decisions taken and methods employed when using the LCM.

  Wellbore Stress Management (WSM) services supply engineered solutions designed to reduce drilling non-productive time (NPT) due to lost circulation. A menu of services and tools is available to support the planning and application stages. Specialty software is used during the planning stage, which leads to the application of unique products and systems during the delivery stage. A feasibility study by technology specialists may include a wide range of tools during the planning stage to support data acquisition, modeling and design of its applications.

  Planning services include hydraulics and fracture characterization modeling to assess expected ECDs and their effect on potential lost circulation intervals. The fracture characterization modeling for borehole stress treatments uses a module within proprietary engineering graphics software to estimate both the expected fracture width and the particle size distribution (PSD) of the materials required to isolate the fracture tip from pressure transmission - thereby preventing its propagation. Application services may include delivery of specialized LCM and systems in either a preventive (pretreatment and/or borehole stress treatments to strengthen the wellbore) or corrective mode (mitigating lost circulation and, where possible, providing additional wellbore strength).

Prevention

  Wellbore Stress Management (WSM) achieves wellbore strengthening by changing the "stress state" around the wellbore. This is done by deliberately allowing fractures to form in the wellbore wall and sealing them with a material of sufficient size and concentration, so that they act as "wedges" to compress the rock within a zone around the wellbore, increasing the "Hoop Stress." The sealing particles must prevent the fracture from closing near the fracture mouth, and they must seal sufficiently to provide fracture tip pressure isolation to prevent fracture propagation. Provided the induced fracture is created and sealed at or close to the wellbore, then an increased hoop stress is established around its circumference.

  Particle size distribution (PSD) of the combination of sealant material...