Research And Application Of Tight Sandstone Reservoir Protection Drilling Fluid Technology In Liaohe Oilfield

Liaohe west depression southern belongs to low porosity, low permeability sandstone reservoir, oil and gas resources are widely distributed, but mining is difficult. For drilling wells prone to collapse, reaming, drilling and other complex cards accidents and reservoir pollution and other issues, the existing drilling fluid system can not meet the rapid drilling and reservoir safety protection requirements, studied the project. It intends to find out by studying the project’s south western of Liaohe depression Shahejie tight sandstone reservoir potential injury factors,the formation of a suitable drilling process of reservoir characteristics in reservoir protection drilling fluid matching technology, technology has reached the leading domestic level.First, the interior block tight sandstone reservoir in reservoir properties were evaluated, and the sensitivity of water locks and other aspects of analysis to determine the major factors of formation damage during drilling presence for: strong alkali sensitivity, middle strong salt-sensitive and water-sensitive and weak stress sensitivity and speed-sensitive reservoir sensitivity damage, water damage to the lock, and the filtrate and solid particles damage and stress, temperature sensitivity damage, while diesel emulsion will also have a very reservoir permeability big impact.Preferably optimized through laboratory tests KCl drilling fluid system, developed a bio-ene-polyol drilling fluid system, and according to the reservoir pore throat size distribution of the two systems were broad spectrum temporary plugging transformation. Laboratory evaluation showed that two sets of drilling fluid system have good thermal stability: KCl drilling fluid system can be anti-temperature 180℃, bio-ene-polyol drilling fluid system can be anti-temperature 150 ℃. Two systems lubricity and anti-collapse suppression is good, strong anti-pollution, fluorescent meet the basic needs of exploratory wells, permeability recovery rate of over 82%,safe drilling, logging and logging requirements west Liaohe Depression, the basic completion of the contract research and technical indicators.This study of drilling fluid system has been first used and test in Lei 27-6(Depth:2200m),with good results, to meet the safety of drilling, logging and logging requirements. Found at the scene of biological polyol ene systems use process easy blistering deficiencies, but can be added to eliminate the anti-foaming agent.