A Drilling Fluid with High Inhibitory Characteristics, Based on Freshwater, Contributing to Increased Drilling Efficiency in More Than 600 Wells at the Salym Oil Fields

摘要

The drilling fluid solution system traditionally used in Russia is a Potassium Chloride (KCl) based, non-dispersive system with a low solid phase content. The use of KCl / polymer water based mud (WBM) is explained by the necessity to inhibit hydration of argillaceous rocks with a high content of smectite from Tertiary and Cretaceous sedimentations. Currently, the use of KC1 based WBM is limited because of their negative effect on the environment. Environmental restrictions pertain to the requirements for water and permafrost rock preservation. The limited used of KCl is also associated with the limited resources for the storage of freshwater for technical needs at the rig sites, and the luck of year-round road. The products delivery to the rig site is possible only once a year using winter roads. For the first time, a freshwater-based drilling solution was used at the Salym Petroleum Development (SPD) project in 2006. The use of the new high performance freshwater-based fluid (HPFWF) ) at the Salym oil fields enabled a significant decrease in the volumes of prepared solution; it also reduced waste volumes, drilling cost, and duration, as well as the cost of delivering chemical reagents. The use of HPFWF enabled a decrease in the drilling solution price, which is one of the important factors when compared to traditional KCl / Polymer WBM. This reduction was achieved through a reduction of the volumes of prepared solution and through a decrease in dilution volumes. The selected system of drilling solution is also an optimal system that enabled us to reduce the time required for well construction. The most important characteristics of HPFWF include flexibility and an ability to easily achieve desirable parameters for the drilling solution, as well as for drilling wells with a complex profile. This paper describes the main principles of HPFWF, as well as its advantages and limitations. This paper also addresses principles of the drilling fluid selection, and optimization. It also demonstrates the mile stones of a project’s progression with HPFWF, and practices used at the SPD project.