Research On Hydrajet Fracturing In Horizontal Wells

Horizontal well is one of the effective ways to stimulate low permeability oilfield nowadays. As the technique perfects the number of horizontal well increases; by the end of 2008, the totale reaches 700 within Liaohe Oilfield, among which 95% were completed with screen pipe, 2% with casing, and 3% openhole. Few of the wells has commercial quantity, most of them has a poor oil&gas show and should be stimulated by frac or acidizing operation. But frac in horizontal well has the following technique problems: one is because that the well path is of wave and cascade pattern, it's hard to trip in/out frac strings, thus has a high percentage operation trouble of sand jamming. Second is because the well has a long horizontal interval, so staged fracturing technique must be used to improve it. But conventional packer and bridge plug is difficult to isolate the interval for screen pipe and openhole completed well. Third is because it's difficult to optimize the frac operation design and control the on-site operation. This article researched on basis of these problems and got the following achievements.1. Improved frac tools, fluid system and other correlated techniques based on theory research.2. Successfully solved the problem of reconstructing the well path of wells with screen pipe, cased hole and openhole completion.3. Successful development of horizontal well fracturing perfects the way of improving horizontal wells and occupants an important position in horizontal well stimulation and oilfield developing.