A Novel Temperature-Activated, Rigid-Setting Material: Case Histories for Drilling and Conformance Offshore Applications
Authors: Vasquez Julio Estuardo 
Published: June 2014

This paper discusses the field application of an innovative, temperature-activated, rigid-setting fluid (RSF) that has been used extensively in inland and offshore operations during drilling, completion, and production stages of hydrocarbon producing wells. In cases of severe or total lost circulation while drilling, conventional lost-circulation materials (LCMs) struggle to provide an adequate solution. If these losses are not controlled in a timely manner during offshore drilling, it can significantly impact the economics of the drilling program as rig time increases. The RSF system has proven successful for curing severe dynamic and static losses by pumping treatments through the drillstring bottomhole assembly (BHA) (no trip out required) because of its highly controllable fast-setting properties. In addition to drilling applications, this system has also been widely used to shut off undesired fluid production (water or gas) during offshore workover interventions in extreme cases where conventional cement slurries or polymer gel systems have yielded low success ratios.

The RSF system is a temperature-activated, rigid, fast-setting fluid that exhibits a unique set of properties. This paper details the specific chemical and mechanical characteristics and field performance of the RSF system. The RSF system is a rigid inorganic " cement-like" setting material that has an exothermic right-angle set; it can undergo a phase change from liquid to an unpumpable clay in a matter of minutes with zero static gel, with a predictable and reliable activation time. Unlike cement, the RSF system is capable of rapidly developing high compressive strength (up to 3,500 psi in less than two hr), creating a plug capable of withstanding high pressure differential and significantly reducing intervention times. The RSF system is generally used for near-wellbore (NWB) applications or for fracture shutoff.

Several inland and offshore case histories are presented in this paper to demonstrate the application of this innovative system, including:controlling severe circulation losses while drilling,permanently or temporarily (depending on the application) shutting off water and gas producing zones,formation consolidation, andsetting annular plugs in the wellbore (cased hole and openhole completions in vertical, deviated, and horizontal wells), among others.

Introduction

Excessive water production from hydrocarbon producing wells is one of the most serious problems within the oil industry. Water tends to become the dominant produced fluid as the hydrocarbon fields mature. Unwanted water production can adversely affect well economics because of water-disposal costs, environmental issues, and reduced hydrocarbon production (Vasquez et al. 2006). Other problems can develop at some point as a result of the undesired water production, including sand production, scale, and corrosion, etc. Water-production problems can vary from (1) leaks in casing, producing tubing, or packers, (2) flow behind casing, (3) water coning (or water cresting in horizontal wells), and/or (4) direct communication from the injector to the producer through high-permeability streaks or natural or induced fractures. Several techniques for controlling water production have been attempted, varying from mechanical to chemical treatments, or combinations of both. This paper describes an innovative temperature-activated RSF system used for water and gas shutoff in NWB applications.