油气层保护技术在二连油田探区的应用

Application of formation protection technology in Erlian Oilfield

二连油田的乌里雅斯太凹陷和巴音都兰凹陷,主要含油层为腾格尔组,含油岩性以砂岩、砂砾岩为主,压力系数一般为0.958-1.035,在施工过程中,钻井液密度应控制在1.25 g/cm3以内。在勘探过程中,油层易发生水敏损害,或在压差作用下,钻井液中的部分固相颗粒被直接挤入地层,堵塞通道,造成油层伤害。采用油气层保护技术与油气层保护剂YD-2B相配合的措施,降低了钻井液密度,有效地防止了油气层的损害。经20多口井现场应用表明,油气层保护剂YD-2B,阻止钻井液滤液侵入地层,减少污染,缩短了钻井周期,有效地保护了油气层。试油结果表明,在乌里雅斯太凹陷和巴音都兰凹陷所钻的探井中50％获得了高产工业油气流,特别是太43井,经过对1872.0-1892.0 m井段油层的试油,获得日产量为14.82 m3的工业油流。

The main reservoirs in Erlian oilfield are mainly consisted of sandstone and glutinite, and the formation pressure coefficient is as low as 0. 958-1. 035 , thus drilling fluid density must be controlled within 1. 25 g/ cm3 during drilling. Water sensitive damage, or solids invention into the formation under pressure differential are the two main causes of formation damage. A set of formation protection technologies are adopted, in combination with the use of formation protecting agent YD-2B, to reduce drilling fluid density and avoid formation damage. The technologies have been used in over 20 wells, and the formation protection results are remarkable, at the same time, drilling period is shortened. Production tests in the exploratory wells drilled in this area show that commercial oil and gas production has been discovered in half of the wells, and a production rate as high as 14. 82 m3 per day has been obtained in well Tai-43.