INTRODUCTION
Horizontal drilling was introduced to the industry in late 80’s. In March 2010 horizontal drilling (HZD) surpassed vertical/directional and in October 2016 HZD surpassed 80% of the drilled wells. Current numbers show HZD accounts for ~88% of drilling in the US. While fracturing has been around since about 1949 there have been many changes in fracing types. There have been changes in fluid types (gelled oils, gelled acid, linear and crosslinked fluids, energized-foamed fluids, acids, N2 and CO2, slickwater, etc.) and proppant types (sand, man-made ceramics, glass beads, etc.). Initially, vertical well principles (best known practices) were applied to horizontal wells.
But fracture models, theories and beliefs were biased by the great successes of vertical well fracturing in conventional rock. Many of these treatments are now believed to be less effective and left under stimulated pay intervals in the lateral. While there have been 1,000’s of re-fracs already performed and numerous papers written on their successes. Many of these show sharper declines in production and lower EUR’s (Estimated Ultimate Recovery) when compared to projections. Moreover, modified processes have the ability to improve profits and EUR’s and many studies have shown that the better the initial production is the better the refrac will be.
DISCUSSION
There is a large opportunity within our industry for success and improvement utilizing current wellbores. There are approximately 910,000 active oil and gas wells in the US (35 of 50 States). This is not a replacement for new drilled wells (or is it?) and parent/child well interactions need to be considered.
To read more, view our white paper with the link below.