Study On Improving Cementing Quality Of Later Development Well In Maturing Field

. Shengli oil field is facing the severe condition of going into later exploratory development after more than 40 years exploitation. In the exploitation of maturing field, the multiple pressure regime, which consists of high pressure zone, constant pressure zone and low pressure zone, has developed in some oil region for long-range high pressure water injection and high volume pumping. High pressure well, absorption well and oil sheet has become the major production method step by step. Along with the increase of exploratory development difficulty, cementing quality can not reach the requirement of exploratory development. Therefore, the problem of improving cementing quality of later development well in maturing field is one technology problem in current cementing engineering.On the base of analyzing the factors affecting cementing quality of development well, the study on improving cementing quality of later development well in Shengli maturing field has been developed in view of the feature of development well and cementing technical difficulty. The cementing technology of cement slurry packing external casing packer can isolate different pressure zone effectively and resolve the problem that pressure difference affects cementing operation. The foamed cement slurry and the slurry with coal ash and micro-silicium have been developed in this paper. The foamed cement slurry has the properties of high compressive strength, good thixotropic property, low permeability, good anti-filtration and temperature tolerance and low cost. The slurry with coal ash and micro-silicium not only has the good stability of conventional slurry but also has the properties of low water loss, high strength and adjustable thickening time.The application of cement slurry packing external casing packer technique and low density slurries have resolved the puzzles met in cementing high pressure gas migration formation, low-pressure/leakage formation and long hole section. They are convenient for constructing in place and significant for improving cementing quality and increasing economic results.